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SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Cylinder Head Baseline Data /cgi-bin/YaBB.pl?num=1542776128 Message started by DragBikeMike on 11/20/18 at 20:55:28 |
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Title: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 20:55:28 The cylinder head is the heart of the system. The amount of air admitted to the engine is dependent on the ability of the cylinder head, and its associated ports, valves, and combustion chamber, to flow freely. You can install all sorts of high flow components like air filters, carburetors, exhaust pipes and mufflers, but the engine’s ultimate performance will always be limited by the capability of the cylinder head to allow maximum flow. It’s easy to add more fuel, but difficult to add the additional air required to burn the fuel effectively, and at the correct air/fuel ratio to achieve maximum power. Therefore, power is limited by the amount of air introduced into the cylinder. We currently don’t have a lot of data on the LS650 cylinder head. We know that it has this funny plug that tends to leak, but I haven’t seen any info related to combustion chamber volume, port volumes, valve sizes, valve-to-valve clearance, maximum permissible valve lift, valve spring seating pressure or spring constant. This post is intended to provide pertinent data on the LS650 cylinder head, so we can make informed decisions about modifications we intend to perform. This data will help us plan for mods like high lift camshafts, increased compression ratio, larger carburetors, porting, increased valve size, exhaust systems, etc. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 20:57:43 I’ll start by listing data that would be necessary to decide things like what cam can be installed, or how large the intake valves can be, or where the compression ratio will end up. I will then describe why I feel the data is important, and then finish off with some pictures and descriptions of how the measurements are taken. The following is a list of measurements that most certainly will be useful. I took these measurements from a used cylinder head that I recently purchased. The head appears to be in pristine condition and obviously has very little operating time. If you have no interest in how the data was obtained, the list is there for your consumption. If you are curious as to how the measurements were taken, continue reading the post after the list of data. I hope some of you find the data and info useful. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 20:59:38 Valves Intake valve head diameter: 33mm (1.30”) Intake valve O/A length: 98mm (3.855”) Intake valve face to keeper groove centerline 94mm ((3.700”) Intake valve keeper groove diameter: .225” Intake valve stem diameter: .2742” Intake valve weight: 49 grams Exhaust valve head diameter: 28mm (1.10”) Exhaust valve O/A length: 91.5mm (3.600”) Exhaust valve face to keeper groove centerline: 87.3mm (3.435”) Exhaust valve keeper groove diameter: .223” Exhaust valve stem diameter” .2737” Exhaust valve weight: 43 grams |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:01:52 Clearances & Distances Valve-to-valve (valves at rest): .500” Valve-to-valve (.400” lift both valves): .136” Note: never gonna crash valves together on this engine. Intake valve margin flush with head surface at .079” lift Exhaust valve margin flush with head surface at .081” lift Valve margin to seat OD typical: .060” Exhaust valve margin to exhaust valve margin: .400” Intake valve margin to Intake valve margin: .200” Intake valve spring retainer to guide seal: .430” Exhaust valve spring retainer to guide seal: .430” |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:04:30 Springs Spring free length (inner): 1.445” Spring OD (inner): .825” Spring ID (inner): .625” Wire diameter (inner): .100” Spring weight (inner): 14 grams Spring free length (outer): 1.640” – 1.650” Spring OD (outer): 1.155” Spring ID (outer): .875” Wire diameter (outer): .137” Spring weight (outer): 36 grams Spring assembly installed height (intake & exhaust): 1.300” Spring assembly force at installed height: 52-55 lbs. Spring assembly force at .950”: 136-139 lbs. (.350” lift) Spring assembly constant: 24 lbs./.100” Spring assembly coil bind height: .849” (travel to coil bind 1.300-.849 = .451”) Spring assembly weight (inner + outer): 50 grams Spring retainer weight: 16 grams Spring retainer keeper weight (per set): 2 grams |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:06:07 Ports Intake port opening diameter: 42mm (1.65”) Exhaust port opening diameter: 34mm (1.34”) Intake port volume: 112cc Exhaust port volume: 66cc Combustion Chamber Combustion chamber volume: 57cc |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:13:23 Let’s discuss the importance of the various data. The valve dimensions are useful in purchasing replacement valves. For instance, if you want to install a valve made from titanium rather than stainless steel, or a valve with a larger head diameter, the dimensions will help you find a valve that will fit the LS650 cylinder head. Valve weight is necessary to calculate applicable spring rate for the maximum rpm you intend to use as a limit. Valve-to-valve clearance is important on some engines, but as it turns out, not an important measurement on the LS650. On some engines, for instance Harley Davidson, the intake and exhaust valves are situated close to each other in the at rest position. During overlap, when the exhaust valve is closing, and the intake valve is opening, the valves can run into each other if the cam produces too much lift at TDC. The LS650 geometry is such that even when both valves (intake & exhaust) are opened to .400” (something that will never occur), there is still .136” clearance between the valve margins. We will never have to worry about installing a camshaft that causes valve-to-valve interference. “Valve margin flush point with cylinder head surface” gives you an idea as to how much valve lift will result in the valve margin moving below the head surface. If you want to setup the engine with zero deck height (i.e. top of piston flush with top of cylinder at TDC), then you must be concerned with collisions between the valves and piston at TDC during overlap. When selecting a camshaft, you need to be interested in what TDC lift the cam will produce and be aware that if that TDC lift exceeds the flush point you may have to increase the depth of the valve reliefs in the pistons. If you intend to use a piston with a raised dome (pop-top), like the Wiseco, the problem may become worse. From what I understand, the LS650 piston doesn’t come close to the cylinder deck at TDC (I recall one forum member stating, “you can measure deck height with a tape measure”. Very humorous analogy.). However, most tuners in search of good horsepower numbers try to run around zero deck with a resultant .030” to .040” quench clearance (the head gasket compressed thickness), a condition I intend to pursue. If that’s the cool aid you want to drink, then you must pay attention to where the valves will be during overlap. Valve margin to seat OD gives you some sort of idea how much seat material is available for installation of oversize valves. Usually, oversize valves require installation of oversize seats, but it’s my understanding that sometimes there is enough material in the standard seat to allow installation of slightly oversize valves in the existing seats. Given the fact that there is about .060” between the stock valve margin and the edge of the seat, it looks to me like it might be possible to install valves that are 1mm or 2mm larger. Exhaust & Intake valve margin to margin distance allows you to evaluate whether there is room for larger valves. Looks to me like the LS650 has plenty of room in this department. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:21:26 Spring retainer to guide seal clearance is very important when installing a cam with more lift. If this distance isn’t sufficient, the cam will run the retainer into the seal and guide, and failure will be imminent (it won’t be pretty). On the LS650 cylinder head, when the valve is closed, we have .430” clearance between the spring retainer and guide seal. The general rule of thumb is you want a minimum of .060” clearance between the guide seal and retainer when the valve is full open. So, if you want to maintain .060” clearance then you should limit max valve lift to .370”. Select your cam accordingly. Note that the Stage 3 cam has .393” lift. I have run as little as .030” clearance but that was on full effort machines with the highest quality valve springs available. Some remedies for clearance issues between the retainer and guide seal are special spring retainers that provide additional clearance, or special guides with a lower installed height. Physical dimensions of the springs are useful when you are looking for superior replacements. You need the OD & ID in order to be sure that the replacement will fit. The weights of the valves, springs, spring retainer, and keepers, are necessary to calculate safe operating RPM. The inertia of these components may overcome spring force and cause a loss of valve control. All sorts of bad stuff results from loss of valve control (primarily parts running into each other). Spring force measurements and spring constant are necessary to calculate safe operating RPM. Same reason as described above. The spring constant can also be used to predict what the spring force will be at various lifts. Spring installed height is necessary to establish how much spring force is applied when the valve is closed. Generally, there is a specification for this value, but I can’t find it in the “all-inclusive” Clymer manual. If any of you happen to have that value from perhaps the genuine Suzuki manual, I would be pleased as punch if you could share it. I measured these four relatively new springs at only 52-55 lbs. at installed height. That seems woefully low. In contrast, an old Honda CB350 (circa 1972) with almost identical intake valves, requires about 101 lbs. at an installed height of 1.32”. The old Honda redlined around 10,500 so maybe that justifies springs with half the force on our 6500 rpm engine. Spring coil bind height is very important. If the cam tries to lift the valve beyond the coil bind height the spring goes solid and once again, failure is imminent, and it won’t be pretty. The LS 650 springs coil bind at .849”. Installed height is 1.300”, so at .451” valve travel the spring will go hard. Using the .060” margin of safety you end up with max valve lift of about .390” (.451” - .060” = .391”). Any cam that produces a valve lift over .390” is a “use at your own peril” proposition. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:28:28 Port diameters are useful in evaluating installation of carburetors and exhaust pipes. It doesn’t make a lot of sense to install a 45mm carburetor on a port with a 42mm opening unless you intend to modify the port. Port volume is useful to monitor port modification. Keeping the flow velocity as high as practical is a noble endeavor, since that will maintain good throttle response and drivability. If you get out of hand with the grinder, and increase port volume too much, the drivability will go in the toilet. You might end up with a killer top end at the expense of being able to ride the bike to that lonely road where it’s safe to go WOT. Knowing what the stock port volume is will allow you to monitor your modifications. I imagine small increases in port volume are perfectly OK, for instance, cleaning up casting imperfections and blending in steps at valve seats may increase volume a few cc. The resultant increase in volume and possible decrease in velocity should be more than offset by the improvement in flow. However, if you start making dramatic changes to the port, like raising the top of the port to improve the angle of attack to the valve, you might want to build up the bottom of the port to restore volume to something closer to the stock volume. That will help to maintain velocity. I assume more port volume will result in higher power at higher rpm and reduced low and mid-range power. Combustion chamber volume is necessary to calculate compression ratio. The advertised ratio on the LS650 is 8.5:1. With a 57cc combustion chamber, a 1mm head gasket (7cc volume), 652cc displacement and an assumed deck height of zero, the compression ratio should be about 11.2:1. But then there’s that negative deck we were discussing earlier. That negative deck along with the head gasket become part of the combustion chamber, so instead of 57cc the chamber is more like 87cc (when the gasket volume and unswept cylinder volume are added in). So, you end up with 87+652/87 = 8.5. Fiddle around with those numbers for awhile and you will figure out that the unswept height of the cylinder is about .130”. Add the gasket thickness to that and you end up with .170” quench clearance. Ah yes, the tape measure could certainly be used to measure that. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:30:28 Let’s look at how some of these measurements are taken. The dimensional stuff is self-explanatory, so I won’t go into that. It’s done with calipers and micrometers and is straight forward. Weighing the valves, retainers, and keepers can be done with a postal scale. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:31:55 Checking valve-to-valve clearance is accomplished by setting the valves at the desired lift and then running numbered drill bits between the margins. In the case of the LS650, I had to open the valves all the way to .400” before I could get them close enough to each other to take a reasonable measurement. The valve-to-valve is never gonna be a problem on this engine. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:33:10 Taking the valve lift necessary to place the valve margin flush with the head surface can be accomplished by placing a tool bit across the head surface directly above the valve. Open the valve until it contacts the bit and measure how far the valve traveled. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:34:15 Valve retainer to seal clearance is measured with the retainer & keepers in place. Pull hard on the retainer to close the valve and seat the keepers, then measure the distance from the underside of the retainer to the guide seal. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:35:23 To measure spring installed height, install a spacer of known thickness (in this case .747”) over the guide and in hard contact with the steel spring seat. Then install the spring retainer and keepers. Pull hard on the retainer to close the valve and seat the keepers, then measure from the outer spring surface on the retainer to the spacer. Add the measurement to the known thickness of the spacer to calculate spring installed height (.747” + .553” = 1.300”). |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:36:31 To measure spring installed force, set up a good bathroom scale (the strain gauge type is preferred) on a drill press. I use a large metal plate beneath the scale to make sure that it is uniformly supported. Then place an ample metal plate on the scale platform so that the spring force is not concentrated in a small area, the plate distributes the load. Place the spring assembly close to the center of the plate. Zero out the scale. Then apply force to the top of the spring and retainer until the spring is compressed to the installed height (in this case 1.300”). Read the scale to record force at installed height (55 lbs.). Then continue to compress the spring to a height representative to full open (I chose .950” which equals .350” lift) and take a reading (this spring exerted 139 lbs. @ .950”). The second reading not only gives you an idea of how much force is available at full lift, but also gives you a second data point to be used to calculate the spring constant (84 lbs. increase over .350” compression works out to 24 lbs./.100”). |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:37:17 Compressed to .950” |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:38:12 Measure the spring heights using a simple caliper and a dial caliper. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:39:10 Check coil bind height by inserting the spring in a vice with soft jaws and closing the vice just enough to make the coils start to touch each other. Don’t over do it or you will trash the spring. Make sure to use soft jaws so that you don’t nick the spring wire. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:40:06 The combustion chamber volume and port volumes cam be measured by covering the opening with plexiglass and filling the cavity from a graduated cylinder. I made one plate (4.5” x 4.5” x .125”) to cover the combustion chamber and another disc (1.375” diameter x .125” thk) to cover the ports. The plates must have a hole to allow filling and venting. Seal the plate to the gasket surface using heavy grease. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:40:53 Here’s the combustion chamber ready to measure. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:41:32 Here’s what it looked like filled with 57cc of oil. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:42:39 Here’s a shot of the intake port all leveled out and ready to fill. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:43:37 Here’s a shot of my poor man’s burette. I use a spool of lead wire to hold it upright while I fill it with oil. This operation is messy. By the time you are done there’s ample oil all over everything. But its easy to clean up and the info collected is worth the hassle. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/20/18 at 21:45:57 I hope you find the information in this post interesting and useful. As usual, I invite any and all comments. I had fun on this project, and I learned a lot. Knowledge is power. Best regards, Mike |
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Title: Re: Cylinder Head Baseline Data Post by LANCER on 11/21/18 at 04:37:15 Very interesting info, thanks for your work on this. |
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Title: Re: Cylinder Head Baseline Data Post by Gary_in_NJ on 11/21/18 at 06:12:16 Great series of posts. Thanks for taking the time to explain this in simple language. |
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Title: Re: Cylinder Head Baseline Data Post by batman on 11/21/18 at 08:56:48 Great info Mike, while you have figured the volumes of both the intake and exhaust ports ,I wonder if you could provide some info on the shapes. I have read that the exhaust passage starting at the valve should be 85-88% of the valve's cross sectional area, and increase not more than 6-8% as it reaches the header ,to maintain velocity and not kill proper flow . You said that removing material from the top of the passages could increase flow ,and I agree as in both cases fuel/air and exhaust both tend to hug the long side turns ,but you also said that material might have to be added to the short side turn ,and I wonder how you think this should be done . Welding or Cotronics Corp. Thermeez-7020 ceramic putty (good to 2300F) ? Your opinion please! |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/21/18 at 15:06:33 Thanks for the Kudos. I put a lot of work into this and I think that the info will be very helpful to the folks who are looking to increase their performance. Good comment on the exhaust port Batz. It surely is a challenge. I've spent a lot of time pondering that ugly port and really haven't come up with any practical solution yet. But hope rings eternal. I didn't measure the port size at the valve, but it's a good idea, and I will do it and post the results. Looking at the numbers you provided we can see that the stock port must fall short of 88% to 96% geometry. It's not getting bigger as the flow moves away from the valves, it's getting smaller. The stock exhaust valves combine for a cross section of 1.9 square inches. The outlet of the exhaust port (1.34" diameter) is 1.4 square inches, or 74% of the valve cross section. Then the gasses continue on to the inlet of the header (1.275" diameter) which is 1.28 square inches, or 67% of the valve cross section. So the path is converging rather than diverging. This might be a good thing. The shape of the exhaust port might be fixed due to the thin wall on the top, but the outlet can be opened up to create a more divergent flow path. When combined with a larger header ID the flow path would then be divergent and more on the lines of a conventional system. The differential across the exhaust valve is very high, much greater than the intake, so it is more forgiving in terms of flow. Simply clearing out some of the junk (like the protruding guides) and reshaping the outlet so that the flow path is divergent (or at least uniform and not convergent) and using a reasonably sized header, might unleash the beast. I should have qualified my comment on raising the top of the port to improve the angle of attack. My comment was intended for modification of the intake, not the exhaust. I don't see any practical approach to raising the top of the exhaust port. There just isnt sufficient material up there. One possibility might be to come up with valve springs that are significantly shorter, but still provide ample force and travel. I just finished installing a set of Kibblewhite springs on an old Honda CB350. The Kibblewhite springs were about .125" shorter that stock, but could accomodate up to .465" lift and had more spring force. If a spring similar to that could be found with correct dimensions for the LS650, then the spring pocket on top of the exhaust port could be welded up and machined to correct the spring height, which would then provide about 1/8" of material for removal from the roof of the exhaust port, while still maintaining the original wall thickness. But 1/8" doesn't seem like it would be adequate. It's just too ugly with the steps and such. Another possibility might be to work the sides and leave the top and bottom alone. But then you're faced with increased volume and the associated drop in velocity. I have used a product similar to the one you describe. It wouldn't surprise me if its exactly the same stuff but with a different label. It's JB Weld Extreme Heat Metallic Repair Paste. It's a one-part product (no catalyst), not an epoxy, and good to 2300F. It contains silicic acid, sodium salt, and steel fines. I imagine it probably has some other stuff in there too. After it sets up, it is really hard and also seems to have good adhesion. But I wouldn't feel comfy with it in a port unless it was captured (for instance the stud hole in the floor of the exhaust port). Since the filler material is steel, it will have a significantly different coefficient of expansion from the aluminum, so the thermal cycling will torture the bond between the aluminum and filler. Might be able to grind in an anchor tooth profile for the filler to grab. I used the stuff to seal the joint between the flexible exhaust pipe and Mac header. I applied it to about the top 1" of the flex pipe before I fed it down into the header. I've only logged about 300 miles on it since I put it in, but I haven't noticed any funny business. One of these days I intend to take the header off and pull out the flex pipe to see how it runs with the 1.79" ID pipe. I'll let you know how the putty held up. If I can't get the flex pipe out the putty gets an A+. The exhaust port also has the unique problem of having unequal runners. The left runner is a lot longer than the right runner. Confining metal removal to the left side might be more beneficial than removing metal from both sides. Removing metal only on the left, thus increasing the radius on the left, and increasing the length on the left might force the gas to accelerate. As far as filling in the intake port to compensate for material removed from the top, I'm pondering a Manley product specifically made for intake ports and manifolds. I don't see welding as being an option because the port is so long. I also imagine any significant amount of hot work will result in annealed base material, loose valve seats, etc. I will probably confine my modifications to clean up, blending, tapered guides, possibly larger valves, a good three or five angle valve cut with back-cuts on the valves, stuff like that. |
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Title: Re: Cylinder Head Baseline Data Post by batman on 11/21/18 at 18:17:11 Mike thanks for your reply, I see that you have thought about what could be done to improve flow in the intake and exhaust passages , I agree that perhaps the best that might be done is to remove some material from the walls , at 3&9 O'clock, thus encouraging some extra flow away from the roofs of the passages. Never having done any work on my head ,I wasn't aware that the exhaust passages became smaller (good info ,bad news!) My thought concerning the exhaust header being off center are opposite yours, I thought it might be better to polish the longer left side to encourage higher velocity, and remove material from the right side to decrease it, hoping to encourage the negative pressure wave (if using a cam with overlap ) to arrive at the exhaust valves at, or as near as possible to the same time, to effect better EV. What do you think? |
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Title: Re: Cylinder Head Baseline Data Post by LANCER on 11/21/18 at 18:38:02 With your discussion of the convergent exhaust port to header of the stock system, do you have thoughts on modest mod’s in the port of smoothing out sharp edges and opening the outer ring to 1.5” and then using a header of 1.5”ID OR 1.65”ID...which header size do you consider the most beneficial ? And why ? |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/21/18 at 22:44:34 Very interesting comments. Batz, I can't comment on the negative pressure wave. I just don't know enough about the acoustics involved, and I personally am of the opinion that the acoustic wave pretty much only pertains to open exhaust systems. I can't fully explain why I feel that way, but my gut tells me that if you are dumping this big pile of hot, expanding gas into a can with a bunch of teeny weeny holes, and baffles, and attenuators, the acoustic wave is toast. You need an abrupt change in diameter and pressure to create the acoustic wave. All we are getting when the gas enters the muffler is sudden stoppage. I'm sure that there is a science to all this, and folks with proper credentials have it all figured out, but a shade tree mechanic like me doesn't have the skills or the means to figure it out. So I have to keep my plans grounded in concepts that are more easily adapted to the shade tree stuff. For instance, exhaust systems that are significantly less restrictive rather than "tuned". Regarding your comment about removing material from 3&9 o-clock positions, all I can say is that I've been reading a lot over the last few months. Pretty much everything I see from the so called experts says you want to increase the radius on the long side to improve the angle of attack, and only smooth the short side radius. The experts seem to agree that you don't want to remove a lot of material from the short radius because the port volume increases too much and the gas velocity is adversely affected. What makes this particular discussion interesting is that all the literature I am referring to deals with the roof and floor of the port, not the sides. But I also must add that the experts rarely discuss the exhaust port, they generally talk to the intake. The huge differential pressure across the exhaust sort of makes it a non-problem, at least up to a point. Your comment regarding the converging condition being "bad news" is interesting. I agree that its a bad design, but I consider it sort of good news since it should be easy to remedy. Just gotta be prudent with the grinder. Lancer, I like your question about the header pipe. Every piece of literature I have read and every formula I have tried indicate that the stock header is grossly undersize. But on the same topic, I can find formulas that indicate that a 1.75" ID pipe would be ideal, and others that indicate 1.5" ID is the cat's meow. To complicate the problem, the user of the formula has to come up with the rpm that he or she is shooting for. That simple question becomes very difficult to answer. You might think you want max torque somewhere around 4000 rpm only to find out you miss that low end punch. And then of course that formula stuff is theoretical. I can tell you this, I installed a MAC header that has a 1.79" ID. That seemed to me to be way bigger than necessary, so before I bolted the header up, I shoved an 18" section of flexible exhaust pipe down it's throat. The flex pipe has a 1.5" diameter ID, but its sort of corrugated. The corrugation feature makes the problem complicated since it adds an unknown that the formulas don't address. The bike feels great with that set-up, and I've had to drastically increase the jet sizes (usually a good indication). But honestly, its seat-o-da-pants. That seat-o-da-pants stuff has bit me in the butt on more than one occasion. I believe Rutley is running a 1.75" ID header with a 97mm setup, and he seems to like it a lot (Yo, Rutley, I apologize in advance if I got the numbers wrong). So a trip to the dyno is in order. But I just can't justify paying for dyno time every time I make a small change. So the next time I get some dyno data, it will represent a number of changes, and as such, will be impossible to correlate to any one mod. Regarding smoothing out the sharp edges and opening the outer ring, my opinion is that sounds reasonable and proper. It seems logical. I will probably do it unless I find some good reason not to do it. Smoothing the sharp edges and getting rid of things that upset laminar flow are non-threatening modifications, there is little risk of screwing up the head. Opening that port exit has some risk but it simply seems too logical. It makes no sense to neck it down like that. I will most likely enlarge it to match my final header pipe ID. Now I have a question for you. As I recall, you are located out in Henry, Oklahoma. As far as I know, that's hot-rod country. You got wide open spaces and plenty of opportunity for the WOT stuff. I've heard a rumor or two that you have a pretty swift Savage, and of course you have lots of experience with this beast, and what seems to be the inside track on performance parts. What size header do you run? Have you tried several size headers, and if so, why did you choose your current header size? |
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Title: Re: Cylinder Head Baseline Data Post by zipidachimp on 11/22/18 at 02:50:50 Interesting info: here is something I've always wondered: my bike is now shut down until March '19, 1 or 2 of the springs will be compressed for 6 months, some free length. How long can a spring be compressed without damage??????? 8-) |
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Title: Re: Cylinder Head Baseline Data Post by LANCER on 11/22/18 at 04:37:36 I currently run a header with 1.75”OD & 1.65” ID, all one piece and essentially the same length as the stock header. I do intend to try a 1.5”ID header at some point though. Why did I choose this size ? I had spent a LOT (years) of time shortly after getting my new 96 model Savage in the year 2000 (Fathers Day gift from my son) looking for information on “how to size a header”. There was lots of discussion but actually finding someone willing to offer guidance seemed to be harder to find. I ran across a website that sells primarily header parts for those wanting to build automotive headers for whatever purpose they were in to. “Headers by Ed” was the site. He has built headers since the late 60’s and his criteria for choosing a particular size & length in the header tubes and collector is solely ET & speed in the 1/4 mi. which is what he built for the most, but’s also included seat of the pants feel when appropriate. He has a LOT of info on his sight about theory and practical use, one of which is a listing of cylinder size and hp/cylinder being produced by the engine, and then suggestions of the tube size best to use. The suggested size for our cylinder is 1.5”-1.65” ideally. His rational for what he suggests just made sense to me. I did not understand everything in the theory but his practical approach was understandable. |
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Title: Re: Cylinder Head Baseline Data Post by batman on 11/22/18 at 12:30:28 Zip ,IF your worried about valve spring compression over time ,you need to rotate the piston to TDC on the compression stroke (like when setting valve clearance) when you store the bike, this closes both valves ,allowing the springs to be as fully uncompressed as possible (short of removing them from the motor :) ) |
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Title: Re: Cylinder Head Baseline Data Post by Fast 650 on 11/22/18 at 13:21:20 79747B7670672722150 wrote:
Lancer, doesn't your bike have a 97mm piston? If so, 1.5" is going to be a tad on the small side for higher rpm use. That size will put gas velocity near 300fps at 5000 rpm which is a little below where peak HP occurs.. Ideally you would want to be at 290 fps at the peak hp point. What you will gain at lower rpm you will lose at higher rpm with that size. 1.5" or 1.625" ID is a good size for the stock bore. For the 97mm, 1.625" is the smallest you want to use and 1.75" ID is as big as you would want to use. For the pipe length, that is determined by your cam timing. The formula is (180 + your exhaust valve opening BBDC x 950)/ rpm of your shift rpm=pipe length in inches. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/23/18 at 23:11:07 Zipidachimp, Batman hit the nail on the head with his comment about setting engine to TDC compression for storage. In addition, you could also open the valve covers and back off the adjusters as far as they will allow. In my racing days, the guys with the fastest iron could always be seen popping their valve covers at the end of the event. They had the best valve springs so they took care of them. They would back off all their adjusters to relieve pressure on the valves & springs. Then, when they would arrive for the next event, one of the first things you would see them doing was adjusting their valves. It's a lot of work but a really good set of springs is expensive. Lance, that was a mighty nice father's day gift. Sounds like you have a great relationship with your son. Looks like we all are faced with the same dilemma. Those pipe formulas are a moving target. I found another and it wants piston velocity as a data point. That makes sense but it doesn't take too much searching to figure out that its dark science. Sounds like I need to check out "Headers by Ed". You left out an important tid-bit of info. How does that 1.65" diameter pipe work? So I took the ball and ran with it. I didn't map the ports initially, but this discussion motivated me to finish the job I started. Here is a pic of the exhaust port. You can see that the cross section at the guide boss is sort of "D" shaped (and it's a mighty tiny capital D). The dimensions at that cross section are .66" tall by .96" wide. If you treat that like about two-thirds of a .96" diameter circle, you get .48 square inches of cross section. That's 50% of the valve cross section. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/23/18 at 23:14:39 So I got out the inside calipers, a dial caliper, and some copper wire and mapped out the port. The copper wire works great. You form it to hug the surface of the port, then lay it on a sketch with several data points mapped out and trace the wire with a pencil. Here's what I managed to sketch for the exhaust port. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/23/18 at 23:18:18 That exhaust port is one chop suey port. Now that we have a fairly accurate sketch, we can mark it up and share our ideas with everyone else. Just print it out, mark it up with a colored pencil, and attach it to your post. Here's a sketch of the intake (a much better port). |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/23/18 at 23:23:05 I hope the sketches are useful to all. I'm already thinking about a few improvements that have potential. If you have some ideas, mark up a sketch and post it. Looks to me like the exhaust is even more choked off than I imagined. Maybe I should reevaluate my comment regarding the big differential pressure. |
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Title: Re: Cylinder Head Baseline Data Post by Armen on 11/24/18 at 04:50:12 Excellent! Thanks for sharing your hard work. |
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Title: Re: Cylinder Head Baseline Data Post by LANCER on 11/24/18 at 04:57:53 26202F53515652620 wrote:
I have 3 kids & 11 grands, a son and 2 daughters. I was intimately involved in my kids lives daily from the day they were born and have been blessed with great relationships with all of them. Daily involvement, consistency in teaching and discipline when needed, and all that wrapped in lots of love will yield wonderful benefits for the rest of my life. They are 43, 42 and 39 now. I am blessed. The engine runs very strong, from just off idle up to redline. It pulls hard enough to require some effort to hang on, you cannot just sit back as if on a stroll. I get a bit of a wobble above 80 so I need to address that still but I don't typically go there very often. I think the pipe is sized well for the engine. Fast650: Yes, I have a 97 piston in it, Stage 3 cam and a 36mm round slide with UFO, DAJ & TW. I also have the Barnett clutch pal though don't think it is really needed unless doing a lot of 0-60 & 1/4 mi. runs. The stock clutch did well until after 8-10 such runs before it began to slip a bit. These are the basic charts Ed has that are designed to help with making choices on pipe size. http://https://www.bikepics.com/pics/2018/11/24/bikepics-2811098-984.jpg http://https://www.bikepics.com/pics/2018/11/24/bikepics-2811097-984.jpg |
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Title: Re: Cylinder Head Baseline Data Post by Dave on 11/24/18 at 05:35:42 That is one incredibly ugly exhaust port.....hard to believe that Briggs and Stratton didn't help with the design (or lack of design). I guess it works as designed - but it makes you wonder why they didn't do a better job of making the exhaust port. Does the weird design somehow favor low speed operation over the ability to make HP? Does the weird exhaust port and restrictive ring just before the header gasket somehow fit into the "low HP cruiser" plan? Did Suzuki intentionally make this bike "constrained" - so you would want to move up to something more powerful? Even with the poor design and low HP - I really do enjoy the way my modified Savage runs. It can break the speed limit on every highway in the US, it can go 0-60mph in around 5 seconds and it accelerates quickly enough to 80 mph that I can stay well ahead of most traffic, and so far it has proven to be very reliable. I love tinkering (95mm Wiseco, Stage 3 cam, 34mm Mikuni, cleaned up the intake/exhaust port, lightened flywheel, etc).......but I am also OK that my Savage is not 50HP. I have always enjoyed the challenge of riding slow bikes fast. I often wonder if the flow of the exhaust port can support (or requires) the extra valve lift of the performance cams? Currently my bike runs really strong in the low to middle rpm ...then the engine begins to feel like it is working hard to make power as it gets up toward 6,500 rpm. I need to work on my exhaust system and see if maybe it is a bit too restrictive to support upper rpm power. I am running the stock header and a muffler I built that requires the exhaust to pass through 2 baffles - one is removable....so I should take it out and see if performance improves without the bike becoming too loud. I have been planning on making a 1.5" header for several years - maybe this is the year I will actually get it done. Keep up the exploring DragBikeMike....maybe you will end up with the worlds fastest Savage! |
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Title: Re: Cylinder Head Baseline Data Post by justin_o_guy2 on 11/24/18 at 07:59:16 but I am also OK that my Savage is not 50HP. I have always enjoyed the challenge of riding slow bikes fast. Making riding a Savage a near orgasmic event. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/24/18 at 13:32:46 Lancer, thanks for Ed's cheat sheet. Makes things pretty simple. I think you have the perfect recipe for raising kids, and grandkids. Sounds like they all turned out great. Nice job. Both you and Dave are running stage 3 cams. Are you guys running those cams with stock valve springs, or do you have a better set of springs installed? What can you tell me about the performance spring kit that Web provides? Do you sell those springs or would we have to go directly to Web to get a set? Does the kit come with retainers and keepers? Are the retainers titanium and are they cut back on the underside to accommodate more lift? The stock springs and retainers limit travel a bit. With the stock setup and the stage 3 you should only have about .037" clearance at max lift. Would be nice to have more since the stock springs are pretty soft. Did you guys do anything to address that? If not, then its a pretty forgiving system. Dave, regarding your comment about the "restrictive ring just before the header gasket", based on the measurements I took at location "B", that 1.34" ring at location "D" shouldn't be holding anything back on the stock configured port. The cross section at "D" is about 150% of the two "B" cross sections combined. Shouldn't have to do anything at "D" until those bottlenecks are improved or eliminated. Please let us know about your springs and retainers. It would be very helpful. |
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Title: Re: Cylinder Head Baseline Data Post by batman on 11/24/18 at 17:40:57 Dave said, "I often wonder if the flow of the exhaust port can support (or requires) the extra valve lift of the performance cams? Currently my bike runs really strong in the low to middle rpm ...then the engine begins to feel like it is working hard to make power as it gets up toward 6,500 rpm." The fact that the performance cams have extra exhaust valve lift is probably the reason they work so well. The extra lift keeps the valve head farther out of the exhaust stream, and the lift adds to the duration ,giving added time to extract exhaust gases. At 6500 rpm that is about 18.4 milliseconds, and our ugly port needs all the help it can get, but perhaps that isn't enough. It maybe that the intake ,with 36 VM carb is too effective, or the fact that the domed 97 mm piston which protrudes into the combustion chamber(making it smaller) ,causes a higher percentage of exhaust gases to fuel/air mix,(there are exhaust gases left behind anytime the motor exceeds peak torque 3500 to 4000rpm ) It may pay to try decreasing intake valve lift or to try wave tuning the exhaust, shortening the Exhaust header from the stock length of 32 inches ,toward the limit of 30 inches may increase scavenging rate for the motor at those higher RPM's.(the wave reverses at the exhaust's first enlargement , the wave travels at the speed of sound-mach 1 - exhaust gases travel down the pipe at about 350 feet/per second) . removing the baffle in the muffler may have little effect. All this is of course OPINION . |
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Title: Re: Cylinder Head Baseline Data Post by LANCER on 11/25/18 at 02:42:26 52545B27252226160 wrote:
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Title: Re: Cylinder Head Baseline Data Post by LANCER on 11/25/18 at 03:36:49 5556435A5659030F370 wrote:
This is just a seat of the pants observation but why would you want to shorten the header to move the power up to a higher rpm when the Stage 3 cam already peaks power & torque in the 4000-5500 range where we ride most of the time ? How do you define "too effective" regarding the 36 carb ? If you are thinking it supplies too much fuel, then just re-jet and tune. This is again just my seat of the pants observation since I'm not financed for Dyno runs with the nearest at least 70 miles away, but I can feel the increased power pulses with the Wiseco piston and the increased responsiveness with the 36 carb. I truly wish I had a Dyno in the shop, I would run after every single change I made but unless I happen to win a lottery that won't happen. Maybe some day. |
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Title: Re: Cylinder Head Baseline Data Post by Armen on 11/25/18 at 05:48:28 So, with all this, how do you think the Mac 1.75" system would work with a 695cc, ports cleaned up, stage 3 cam, big carb, K+N filter set-up? |
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Title: Re: Cylinder Head Baseline Data Post by Ruttly on 11/25/18 at 08:11:48 I find trying to extract power from this engine,to say the least challenging ! Lancer trying to compare that old BSA to a LS might be missing the mark. Note: I highly respect his opinions and his knowledge , after all he has contributed to what I know to be true about the LS. When you compare engines it more about what is different than what is the same. And for now let's leave the cams out of it. First thing everyone looks at is bore & stroke, for me not so much cause you won't find a huge differences. Guessing game going here , oh yeah. Clue: Only one member has gone there( that I know of). ;D |
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Title: Re: Cylinder Head Baseline Data Post by Ruttly on 11/25/18 at 08:21:28 Guess I should have left you with a question rather than a statement. What's the biggest difference between the two engines in stock form ? Shush Armen . |
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Title: Re: Cylinder Head Baseline Data Post by LANCER on 11/25/18 at 08:21:53 5B68777F741A0 wrote:
MAC ran a contest on this site when they first began to advertise the system and before it was actually available. I won the contest and the system, though it took them months to deliver it and then only after several of us sent letters asking “where the heck is it ?” I mounted it on two of my bikes, my ‘96 (REX) and an ‘09 S40 with a Webcam. Both machines suffered performance lose with the larger header, which concurs with the charts by “Headers by Ed”. So the header I did not care for, it was too large, but the muffler I did like, it had good sound. |
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Title: Re: Cylinder Head Baseline Data Post by Armen on 11/25/18 at 08:23:33 Thanks Lance. Guess I have to find an outfit that will make a stainless header in the stock shape, with a slightly larger ID. |
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Title: Re: Cylinder Head Baseline Data Post by batman on 11/25/18 at 08:38:30 Lancer, I was speaking to Dave's comment that his bike seemed to be struggling as it approached 6500 rpm/max speed, and my comments were addressed to that end ONLY. I didn't mean to nock the use of the 36vm carb , it's smaller throat adds velocity to the incoming fuel air mix ,increasing swirl in the combustion chamber adding a more complete burn ,as does the higher compression of the DR piston, but due to the decrease in combustion chamber size, that the lift of the intake lobe might be reduced slightly without an actual loss in hp. ,give a smoother running motor and higher mpg. Due to the fact that after market cams do have overlap wave tuning the exhaust for high speed is possible , and extraction of exhaust gas from the cylinder leaves more room for the incoming fuel/air charge creating more HP. Advancing the cam (2-4 degrees) might be an other option, the early opening of the exhaust valve would allow higher cylinder pressure an may speed exhaust removal as well as the earlier opening of the intake valve might assure faster /more complete filling of the combustion chamber (even more so if combined with wave tuning). |
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Title: Re: Cylinder Head Baseline Data Post by LANCER on 11/25/18 at 08:40:28 6B58474F442A0 wrote:
I made my first one using shaped pipe sections purchased from an exhaust pipe supplier, cut and welded into the desired shape to match the stock unit and cut the head from a stick pipe and welded that on. It worked well and lasted several years before falling apart due to my “attempt” At welding. The next one I purchased a length of pipe and took it with the cut head from a stock pipe to a muffler shop that builds exhaust systems for cars, with my Savage in my truck, and had them bend the pipe to fit my bike and then weld on the head. That was done 6-8 years ago. Earlier this year while on the Texas ride the head and pipe cracked just behind the head so I had it welded by a local welder with much better skills than the other guy, so it is up and running again. |
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Title: Re: Cylinder Head Baseline Data Post by LANCER on 11/25/18 at 08:52:07 Batman, I did understand that your comments were directed to Dave and I take no issue with you at all. I simply wanted to add my observations. It was my error for not being clear with my intent. All is good. |
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Title: Re: Cylinder Head Baseline Data Post by Fast 650 on 11/25/18 at 08:56:05 17243B3338560 wrote:
Summit Racing and the like sells stainless bends and straight sections for people building their own headers. If you are careful with the cuts and measurements, two 180 bends and one 48" straight section will make two header pipes. I get a discount from Summit through work, but it was only about $60 for enough to make two pipes. |
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Title: Re: Cylinder Head Baseline Data Post by batman on 11/25/18 at 09:14:01 Lancer, no offence was taken ,nor any meant be me ,as I stated . it was just opinion, meant to make anyone aware of options that might be helpful,and your right- It's all good! |
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Title: Re: Cylinder Head Baseline Data Post by LANCER on 11/25/18 at 09:53:28 Armen, following my receipt of the MAC system I had several exchanges with the MAC rep who had posted to contest on this sight, and asked him if they had run Dyno tests on their pipe when deciding to go with the 1.75” ID /2”OD HEADER PIPE. He claimed they did and that that size worked best but I have a difficult time believing they actually did so. It just does not prove to be the case on the road. That was my experience anyway. |
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Title: Re: Cylinder Head Baseline Data Post by justin_o_guy2 on 11/25/18 at 10:07:43 A rudimentary dyno shouldn't be beyond the abilities of most of us here. |
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Title: Re: Cylinder Head Baseline Data Post by Dave on 11/25/18 at 10:52:14 383B2E373B346E625A0 wrote:
I was a bit afraid of posting my feelings about my power profile of my engine.......I don't remember saying it was "struggling". It runs far better than a stock engine at all rpms. The little 250 Ninja runs smoothly below 8,000 rpm - then it just screams from there up to 14,000.....it pulls strongly in the upper rpms. My Savage does just the opposite - it pulls really strong in the lower and mid rpms, then when you get up over 5,500 rpm it just loses a bit of "enthusiasm", and it lets you know that it is definitely time to shift to move the engine back into the 4,000 - 5,500 rpms where it pulls harder. It can rev past 6,500 rpm easily in the first 3 gears when under full throttle and you have to be ready to shift as it goes through the gears quickly - it just doesn't pull all as hard when you approach the upper limit of the rpm range. The bike reaches 80 mph easily, 90 comes with a bit more work....100 takes a good while and there really isn't much left. It could be that the exhaust system is holding the breathing back a bit....not sure. The engine runs really well for the style of riding I do, which is 40-60 mph twisty roads - the torquey engine is well suited to pushing the bike along at a very comfortable pace....I am not one that uses full throttle very often, and I very rarely explore the terminal velocity. That said, I fully support exploring the potential of the engine, and I believe some work in finding the "actual" compression ratio of the Wiseco is necessary (Is it really 10.5:1 when installed in the Savage)? It could be that it is not necessary to run Premium if the compression ratio is only 9.5/1. |
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Title: Re: Cylinder Head Baseline Data Post by Fast 650 on 11/25/18 at 12:07:38 Cylinder pressure will dictate what octane rating you need. It is possible to have 8:1 CR and ping like crazy with an emissions type cam. Or have 11:1 CR and a long duration/lotsa overlap cam that is happy on 87 octane. Don't let high static compression ratios mislead you because the actual cylinder pressure can be lower or higher than the compression ratio suggests. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/25/18 at 17:22:14 Wow! Lots of activity here. This is getting interesting. Regarding Lancer's comment "Keep in mind that the Stage 3 cam is in the low range for cams duration wise, and the lift is nowhere near even the stock DR cam". I recently finished mapping out a Stage 3 that Dave loaned me. The Stage 3 cam has the following max lift numbers, .393" Intake, .376" Exhaust. The stock 1995 DR 650 cam has the following max lift numbers, .365" Intake, .364" Exhaust. So the Stage 3 actually has a bit more lift than a stock DR650 cam. Regarding DR springs vs LS springs, the parts fiche shows that the DR & LS use identical springs, part #12920-37402. The retainers are also identical, part #12931-4500. Lancer, I really appreciate your input regarding your spring setup with the Stage 3 cam. It tells us a lot about how forgiving the valve train is. With that cam having faster ramps and higher lift, combined with a relatively close proximity between retainer & guide seal at max lift, the fact that you can wring its guts out on a regular basis sets us all at ease. Looks like that puppy can take it. Also, great info on the Mac header. It pretty much tells the story on header ID. Seems to me that the book is closed on that topic. All the formulas, tables, charts etc. indicate the ID of choice should be between 1.5 to 1.625", and it seems to me that we have testimonials that support that. Regarding Dave's comment, " it just doesn't pull all as hard when you approach the upper limit of the rpm range. The bike reaches 80 mph easily, 90 comes with a bit more work....100 takes a good while and there really isn't much left". As you increase speed, the wind resistance increases exponentially, its not a linear function. So its natural for your acceleration rate to decline dramatically as you exceed 70 or 80 mph. Your on top of one of the most aerodynamically challenged vehicles ever designed (an unfaired motorcycle). It's like trying to push a sheet of plywood through the air. In addition, it's a single cylinder. Multi cylinder engines have shorter periods of time between power impulses, so multi cylinder engines have a much easier time plowing through the wind. That single cylinder takes one step forward on the power stroke, and three steps backward on exhaust, intake & compression strokes. As far as your compression is concerned, as I recall you reported on another thread that you have somewhere on the order of 195 psi cranking pressure. I'd say that you need to stick with premium fuel. The Stage 3 cam closes the intake valve at 38 degrees ABDC, the stock cam closes the intake at 40 degrees ABDC (those numbers were measured at .050" lobe lift). So the Stage 3 cam actually closes the intake sooner than the stock cam, which in turn increases your effective compression stroke by 2 degrees. Add in the pop top Wiseco and your in premium fuel territory. No sort of vacuum retard feature to pull timing out under load and you really have no choice. Too risky to run 87 or even 89 octane. The Stage 1 that you were previously running closed the intake at 40 degrees ABDC, so with that cam, your effective compression stroke was identical to stock. I agree with Fast650, the cylinder pressure is a key factor in fuel selection, but we should also consider other factors like ignition timing and quench clearance. The LS650 has effectively no quench since the piston doesn't get close to the cylinder head at TDC, and the timing really can't be adjusted too readily. Maybe that's why the advance curve is so darned shallow. When I did my timing test the first thing that struck me was how high I had to rev the engine to achieve full advance. I don't have a tach but that puppy was really singin by the time it stopped advancing. Maybe the OEM simply dogged out the curve to avoid any detonation problems. Pretty easy solution, set the compression ratio in limbo land (how low can you go), and advance timing at a snail's pace. Some more low hanging fruit? We shall see. Stay tuned for a cam comparo. I have to remove the DR650 cam to do a better map and plot a curve. Then I can finish it up. The reason I posted the head data first was because I wanted to be able to see if the cams are all bolt-in. Seems they are. With all the cams plotted out on a bell curve, we can then move on to trying to improve cylinder head flow, and figuring out what improvements can be made to flow at lower lifts & higher lifts. That will make selecting a camshaft for the combination a bit easier, and also help in deciding what head mods will work best for a particular riding style & budget. |
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Title: Re: Cylinder Head Baseline Data Post by batman on 11/25/18 at 19:25:16 While DBM notes that wind speed increases exponentially, then so must the hp needed to increase speed, consider for a moment that category 1 hurricane speed is 74 to 95 mph, and category 2 is 96 to 111 mph , if your bike does 100 , even on a calm day, it's doing very well . No matter how long it takes to get there. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/26/18 at 13:27:20 I was going through some of my old Harley notes and came across a printout of a dynamic compression ratio calculator I used. It's really cool and provides a lot of interesting info. You will need the rod length, bore, stroke, combustion chamber volume, intake valve closing point, calculated static compression, etc. Try it out. http://www.rbracing-rsr.com/comprAdvHD.htm Here's a look at what the calculator provides. |
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Title: Re: Cylinder Head Baseline Data Post by ohiomoto on 11/26/18 at 20:32:51 76696F6875724373437B69652E1C0 wrote:
---------------------------- We had a dyno guy from MN on here a while back. He had experience building big HP bikes and was all in on "exploring the potential" of the LS. He got run off real fast and put his cash into a big custom twin instead :-? |
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Title: Re: Cylinder Head Baseline Data Post by justin_o_guy2 on 11/26/18 at 20:42:12 How long does it take to figure out Very limited potential? |
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Title: Re: Cylinder Head Baseline Data Post by ohiomoto on 11/27/18 at 04:01:01 796660677A7D4C7C4C74666A21130 wrote:
Well, this is page 5, you tell me? ;) I'll stick to my guns and say "more power to ya" to anyone who wants to see what they can get out of our motors. Obviously anyone looking for serious performance wouldn't start with this turd. (I'm pretty sure everyone on here realizes that. The page 5 comment was tongue & cheek.) But sometimes the journey is more satisfying than the destination. This motor/bike just draws people to it in an "oldschool" way. We have people turning them into classic cafes, bobbers, choppers, scramblers and trackers, and we have style people trying to coax a few extra ponies out of it and "doing the ton" like they did in the good old days. Good times. :) |
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Title: Re: Cylinder Head Baseline Data Post by Dave on 11/27/18 at 04:59:56 2F28292F2D2F342F400 wrote:
Not sure if he left because we were too tuff on him - or he learned that the Savage is not going to get him any big HP numbers or low ET's. He hasn't posted anything in 5 months - but did log onto the site 3 weeks ago. Every couple of years we get a new member who is going to turn the Savage world upside down and turn it into a big HP power monster....then reality sets in. DragBikeMike is going about it in a far more methodical/schooled investigation........and may well find a few HP that has never been available previously. "MORE POWER TO YOU"! |
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Title: Re: Cylinder Head Baseline Data Post by LANCER on 11/27/18 at 05:22:45 I am still amazed at what Suzuki did. Why in the world would they create 2 engines when one will do ? Why bless one with GOOD DNA while the other was given 'Not so Much" type DNA ? Clearly, the LS650 was designed and built to be a "Sacrificial Lamb" for their cruiser market. A very sad thing for Suzuki managers who made this decision. But, we have fun with it in spite of that. ;) |
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Title: Re: Cylinder Head Baseline Data Post by ohiomoto on 11/27/18 at 05:58:43 447F7265747863657E767B64170 wrote:
I agree, more power to you DragBikeMike! I'm not one to judge how someone goes about it, I enjoy seeing what people come up with. It's all good in my book and long is it's not my checkbook. :) |
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Title: Re: Cylinder Head Baseline Data Post by Ruttly on 11/27/18 at 10:24:05 I'm not here to discourage anyone from trying , cause every time someone tries I learn another tidbit of info. DBM is no dummy and is going about it correctly. But the rest of us collectively are pretty dang smart too. I have ideas to try just no time or money to dispose of. We all have what it takes just maybe not the will , I think we are somewhat satisfied with the improvements and power increases. But do we want to sacrifice dependability for H/P , I hate pushing when I should be riding. |
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Title: Re: Cylinder Head Baseline Data Post by Dave on 11/27/18 at 10:59:19 17303131293C450 wrote:
I am with you - both in reliability and durability. Being able to make more power by increasing efficiency and breathing ability should not cause things to wear out or break. I am pretty satisfied with the increase I got from the Wiseco, cam, carb, light flywheel and mild porting changes - especially since most of my riding is done at 1/2 throttle or less. I wear my tires out in the curves.....not by accerating hard down the straight sections. I am not opposed to finding out how things could be improved beyond where we currently are.....is there some HP that has been elusive? :-? |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 11/27/18 at 11:48:15 All these comments are great. Everyone has their own personal goals. Mine just happens to be making a silk purse from a sow's ear. I know it's not practical, but it certainly is gratifying. I've had just about every sort of two wheeled vehicle you can think of, from dirt bikes to drag bikes, with cruisers and sport bikes in between. I've had little two-cylinder two stroke buzz bombs for daily commutes, dressers, scooters, motocross and trail bikes, and a nitrous fed, 171 HP Harley drag bike. All were a complete kick in the pants. As one of you folks said "It's all good.". I bought this Savage purely as a soup up bike. I wanted to see what I could do with something that had almost no potential. I owned one of the old four-speed Savages years ago (pre 1990). I liked it for the look and good low end grunt, but also knew that there wasn't much of a selection of after market parts. That meant any significant improvements to performance would be a real challenge. It would require some innovation and a lot of hard work. So now I'm on my journey. If the project is a flop, I will still be mighty gratified. I will learn a lot, and have the pleasure of sharing the information. I love being on this forum and having the opportunity to learn from all of you, and share with all of you. I'm getting old and slowin down a bit, but this is one old dog that CAN learn a few new tricks. |
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Title: Re: Cylinder Head Baseline Data Post by Ruttly on 11/27/18 at 11:56:29 Oh yeah there is still H/P on the table , but is it worth the money and at this point is where we trade H/P for rock solid dependability ! My bike is fast and I haven't even done the stage 3 cam yet and I may not. So ask yourself what you are willing to do about it. |
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Title: Re: Cylinder Head Baseline Data Post by Ruttly on 11/27/18 at 22:14:08 When I started the RYCA tracker project , like DBM it had a plan to be a stock motor with a pipe. Then I was lead astray and jumped in with both feet. But a fantastic project with members to fall back on when I got stuck. Wish I had 5k to buy another bike and build a motor like DBM has planned. I know that motor has more to give , I'm just not sure if it would hold together. It really wasn't designed to be heavily modified , unlike the old Yamaha XT/TT/SR 500s ,what a great motor from meek n mild to absolutely gone Wild race engines. I would love to dump about 2k on a next level motor just for fun ,it wouldn't be nothing to look at just a light to light bike. I am accepting donations of spare engines 96 or later , actually any year will do for a mock up motor. |
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Title: Re: Cylinder Head Baseline Data Post by justin_o_guy2 on 11/27/18 at 22:42:29 Buy a motor. |
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Title: Re: Cylinder Head Baseline Data Post by ohiomoto on 11/28/18 at 05:37:02 I apologize as my comment seems to be taking this topic in a different direction. For the sake of keeping DBM's thread on topic, we should probably cease and desist discussing the actual merits of his endeavor. |
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Title: Re: Cylinder Head Baseline Data Post by Ruttly on 11/28/18 at 05:53:38 Yeah I was trying to egg him on a bit , I wanna see what he comes up with! |
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Title: Re: Cylinder Head Baseline Data Post by Dave on 11/28/18 at 06:32:47 Straying off topic is common in the winter......we are get bored and are easily distracted. |
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Title: Re: Cylinder Head Baseline Data Post by Ruttly on 11/28/18 at 09:45:28 My meds don't help any ! |
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Title: Re: Cylinder Head Baseline Data Post by LANCER on 11/29/18 at 03:34:43 496E6F6F77621B0 wrote:
You are taking the wrong med’s then ! Step it up and you will rest in a foggy bliss. |
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Title: Re: Cylinder Head Baseline Data Post by Ruttly on 11/29/18 at 10:08:20 Already there buddy , already there. ;D |
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Title: Re: Cylinder Head Baseline Data Post by LANCER on 11/29/18 at 10:54:52 46616060786D140 wrote:
I understand, some fog is a daily norm in my world as well, been there since the mid 90's. For me chronic pain and med's for it just tend to cancel each other out somewhat; no high, nothing goofy, just a moderate decrease in pain level and some relief. There is never total pain removal, only some relief. |
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Title: Re: Cylinder Head Baseline Data Post by batman on 12/04/18 at 09:17:36 OK, let's get back on track (sort of) . I've been doing a bit of research on four valve heads and thinking about how to increase swirl so as to increase fuel and air mixing, to get a more complete burn, and gain more hp. Surprisingly enough our 4 valve head creates no swirl ! The intake valves being open and the piston rising on the compression stroke instead produce a tumbling action. All is good until the compression stroke actually starts ( when both valves are closed and the piston is still rising to TDC) at which time there is little to no tumbling or swirl action just when it is most needed. What can be done? At this point I have found only two ways ,both of which involve the addition of swirl. the first rather complicated (and pricey) is a 4 valve custom head with 4 different size valves , a larger and smaller intake and larger and smaller exhaust valve. the larger intake is placed opposite the smaller exhaust valve ,the smaller intake opposite the larger exhaust . This creates a swirl even with cams that have overlap. The second is much less costly , and something I've talked about before. The Singh groves ,because they are in the squelch area and could induce swirl when needed most, I'm guessing that the small increase in cylinder head displacement would be compensated by the hp increase ,reduction of the squelch height would add to their effectiveness. |
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Title: Re: Cylinder Head Baseline Data Post by Dave on 12/04/18 at 10:26:58 5A594C5559560C00380 wrote:
Are you calling Suzuki a liar? :-? The Suzuki website states: ENGINE FEATURES The 652cc, SOHC, single cylinder, air-cooled, four-stroke engine with TSCC (Twin Swirl Combustion Chambers) cylinder head and high mass crankshaft produces strong low-end power and torque. https://gsx250.wordpress.com/2009/06/29/tscc-twin-swirl-combustion-chamber/ |
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Title: Re: Cylinder Head Baseline Data Post by batman on 12/04/18 at 15:22:34 IF THE SHOE FITS WEAR IT! What Suzuki is calling twin swirl (a nice catchy name) is really twin tumble , a not so catchy name. Swirl (look it up in the dictionary) is a sideways twisting motion ,and that doesn't occur in our motor. It does occur in two valve heads. It does strike me funny that the picture of the gsx 250 cylinder shows arrows showing the flow as tumbling in the cylinder , yet shows no arrows of it's swirl taking place in the domed sections of the head that is what THEY claim takes place . I think I'm smelling manure. |
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Title: Re: Cylinder Head Baseline Data Post by justin_o_guy2 on 12/04/18 at 16:26:46 Swirl (look it up in the dictionary) is a sideways twisting motion As is evident by looking at the victim's hair. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 12/05/18 at 12:50:42 The unusual head design that Batman discusses is called a "PolyQuad". It is a patented design by David Vizard and another fellow. You can view a very interesting and informative article on the PolyQuad at www.motortecmagazine.net. Mr. Vizard is a wizard, and his books contain tons of pertinent info for the average hotrod enthusiast. He states that 4-valve heads induce tumble, and 2-valve heads induce swirl. The article gives a really good explanation of this, and also contains some excellent illustrations of exactly how his PolyQuad design sets up the swirl and tumble combination. You called it Batz. I guess it's conceivable that Suzuki incorporated some other feature in the ports or combustion chamber that induces swirl. If they did, I can't see it. Seems to me that it would be fairly easy to incorporate a portion of the PolyQuad design into the Savage head. Install one larger intake valve ( I have found some that will probably work), and unshroud the two intakes in that manner shown on Vizzard's illustrations. The larger exhaust valve seems difficult at this point. Short of having Manley, Kibblewhite, or Ferria (sic) manufacture a custom valve, I haven't been able to find any exhaust valves comparable to the LS650 valves (they are much shorter than the intakes). This "Singh Grove" design is a mystery. Do you really mean to say "Groove"? I've viewed some videos of this guy Singh grinding away in throttle bodies. Is that the same guy? Does he now have some sort of mod that he does in the quench area on the cylinder head? Would it be possible to place the groove in the piston instead. Pistons are a lot cheaper. If you don't like the results you can put in a new piston. |
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Title: Re: Cylinder Head Baseline Data Post by Ruttly on 12/05/18 at 15:03:52 Suzuki's intake valves are not oriented to induce swirl ! |
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Title: Re: Cylinder Head Baseline Data Post by batman on 12/05/18 at 15:51:52 MIKE , SOMENDER SINGH grooves are what I was referring to above. They can be used in 2 valve heads where they don't really create swirl (it's already present) ,they are placed in the squish zones on either side of the sparkplug and will help to increase ignition probability. They would do much more in our 4 valve heads as tumble action stops during the compression stroke when the intake valves close ,well over 100 degrees be for TDC. they could effect swirl and ignition probability. The other grove you mentioned is THE GADGETMAN GROOVE used to increase carb /throttle body effectiveness at Idle and lower speeds. I have used this on my stock CV carb and it delivered a 7.3% increase in mpg in highway riding. (It might do better in the city, but I haven't tested this being 60 miles from the nearest one, and not a frequent flyer.) If you were to place a larger intake in the head I would unshroud ONLY that valve to create swirl , also the wall of the head behind this valve is voluted so the velocity from the rear of the valve is changed to pressure as it moves in the direction of the sparkplug adding to the swirl. |
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Title: Re: Cylinder Head Baseline Data Post by LANCER on 12/05/18 at 15:56:51 Our combustion chamber is a small flat space with the spark plug centered, so what more can be done EFFECTIVELY to increase fuel burn to produce more power ? Seems like addressing the exhaust port would be more beneficial, as well as bumping the CR up another point. The stock DR650 had a 9.7:1 CR, & a wide open exhaust port. The stock DR piston is also a flat top and a 95mm bore so I assume the piston set slightly higher in the tube to create the added point of the CR. With that said and all the additional info shared in this and other threads, I now believe that we need to increase the height of the piston crown to bring up our CR to a true 10.5-11.5 range...safe space permitting of course. |
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Title: Re: Cylinder Head Baseline Data Post by justin_o_guy2 on 12/05/18 at 17:31:43 I'm reminded of the table in the student union building where the geeks with slide rules, pocket protectors and Dungeon and Dragon game pieces in their pockets congregated. |
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Title: Re: Cylinder Head Baseline Data Post by batman on 12/05/18 at 18:40:44 Bumping up the CR, from an already high one, will do little, raising compression from the first point,8.5 to 9.5 shows the most increase of about 5.5 % more power ,then raising it from 9.5 to 10.5 only shows about 2.2% more. Raising CR to 11.5 might be a wasted effort if increasing piston dome height, because you're also making the combustion chamber smaller,which means less room for the incoming fuel/air charge. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 12/05/18 at 21:59:18 Actually, the benefit from increasing compression height (wrist pin centerline to top of piston), would be establishment of an actual quench zone. With the current design, there really isn't a quench zone (tight clearance between the overhanging head surfaces and the top of the piston). Reports on this forum state that there is something on the order of .160"+ between piston top and cylinder head when the piston is at TDC. It should be .040" or less. If the piston compression height were increased to establish .040" quench, and the pop-top removed (i.e. flat top piston) you end up with increased compression ratio plus a reasonable quench clearance. So how do we go about getting these flat top pistons with increased compression height? |
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Title: Re: Cylinder Head Baseline Data Post by batman on 12/06/18 at 00:37:21 Well we could start by removing the gasket under the cylinder using a very thin layer of sealer should work, but that would only shave about .018 off the quench, not much, but it's a start. The problem of shaving the cylinder head and removing this gasket to achieve proper quench would be to deal with the slack this would put in the cam chain. |
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Title: Re: Cylinder Head Baseline Data Post by LANCER on 12/06/18 at 03:52:07 So on the original version of my engine when I had the head shaved .015” and the cylinder shaved .025” for a total of .040” with 94.5” bore and a Suzuki flat top piston, Compression would be brought up to ..... ?? It did run very well with the original Stage 1 cam and 36 VM. This would leave the quench zone intact. My cam chain was not just flopping around, there did not seem to be any noticeable change in the chain tension. The tensioner may have been out ever so slightly more, but for a change of just o.o4” ... REALLY ? I have a hard time seeing any issues with the chain. |
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Title: Re: Cylinder Head Baseline Data Post by Dave on 12/06/18 at 04:42:02 We had a thread on the squish and piston/head clearance a while back before DragBikeMike came along, and Batman brought up the Somander Singh grooves......it did not come to any fruition. http://suzukisavage.com/cgi-bin/YaBB.pl?num=1518089629/0 The Wiseco literature claims their pistons provide a 10.5:1 compression - however I believe that number comes from the DR650 application, and not for the piston when used in the LS650. At this point, nobody knows for sure what the actual Compression is when the piston is used in the Savage. |
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Title: Re: Cylinder Head Baseline Data Post by batman on 12/06/18 at 08:01:44 Lancer, the stock head is 57cc when the stock quench is added ,total volume comes to 87cc. Your removal of .040 would reduce that to about 80cc ,using the formula for compression that would work out to; 80+652/80 =9.15 :1 .but this doesn't take into account the reduction caused by a domed piston ,use of the domed DR piston would drive compression higher .and reduce chamber volume .If someone could determine the displacement of just the domed area of the DR piston we could subtract that from 80 and get a hint of what the actual compression is in our bikes using it. The problem with the cam chain isn't that it's flopping around ,its that the slack caused by your .040 reduction is really seen as .080 for the double sided chain ,and all of that is taken up on the back side by the cam chain adjuster. How much does that retard valve timing? has the chain ages it becomes worse. how does this affect performance? |
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Title: Re: Cylinder Head Baseline Data Post by justin_o_guy2 on 12/06/18 at 08:53:13 Someone came up with a way to advance the cam by moving a gear on a spline, IIRC. Was it Arlen? |
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Title: Re: Cylinder Head Baseline Data Post by Dave on 12/06/18 at 08:54:36 2E3137302D2A1B2B1B23313D76440 wrote:
It was Armen. I have linked the thread a time or two....I don't know where that thread is at the moment - it would take some searching to find it. It involves the fact that the number of splines where the crank sprocket mounts is different than the number of teeth - so by turning the sprocket on the crank and moving the chain on the teeth, you can advance/retard the timing in pretty small increments. |
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Title: Re: Cylinder Head Baseline Data Post by batman on 12/06/18 at 09:16:48 and the advance was 2.58 degrees. |
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Title: Re: Cylinder Head Baseline Data Post by Dave on 12/06/18 at 09:38:36 Found it! http://suzukisavage.com/cgi-bin/YaBB.pl?num=1476554649 |
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Title: Re: Cylinder Head Baseline Data Post by justin_o_guy2 on 12/06/18 at 12:09:23 Well, put the dang thing somewhere safe.. |
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Title: Re: Cylinder Head Baseline Data Post by LANCER on 12/06/18 at 12:41:25 4C4F5A434F401A162E0 wrote:
So you are saying that the extra slack in the chain caused by the reduction causes the timing to be retarded ? If that is the case then why is the timing not retarded when the chain just naturally stretches ? Isn't that the same thing ? Both create extra slack. I thought the chain would have to slip a notch to do such a thing, or a new pin hole created to manually shift the sprocket position. The timing is held in place by the bottom drive sprocket and the cam sprocket on top (the chain is in tension on this front side) and that does not change regardless of the amount of slack on the back side. Am I missing something here ? |
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Title: Re: Cylinder Head Baseline Data Post by justin_o_guy2 on 12/06/18 at 12:53:57 The timing is held in place by the bottom drive sprocket and the cam sprocket on top (the chain is in tension on this front side) and that does not change regardless of the amount of slack on the back side. The chain stretch allows the cam to slowly retard. Since a bit more than half the chain is trailing, less than half of the chain stretch is between the crankshaft and cam. Hafta do the math to determine exactly how many degrees of rotation the change in the length of the links between crank and cam would create. |
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Title: Re: Cylinder Head Baseline Data Post by verslagen1 on 12/06/18 at 13:00:09 293A2D2C333E383A316E5F0 wrote:
Or 1° for every .010" chain stretch. I would be interesting to know what the cam timing is with a new chain. And how much tolerances affect cam timing. |
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Title: Re: Cylinder Head Baseline Data Post by LANCER on 12/06/18 at 14:13:49 Reading the discussion of the possible difference between the measurements of the DR vs LS from piston top to top of cylinder. I did get a spec from Wiseco on that the distance from the top of the pin to the deck is 0.0607", and from the center of the pin to the deck is 1.128". However I'm not so sure that I got everything correct. Why ? Because I was wondering about how this is useful when it occurred to me that I can compare a DR piston, of which I have a several, to a LS piston. So I did. Now these measurements are not exact because I could not find my digital caliper but did find a manual one. The crude findings are: Measured from top of piston pin to base level of the piston top. DR: 17.2mm LS: 16.6mm Different from what I got from Wiseco. Even if this is not absolutely accurate, in relation to each other the difference remained at about 1/2mm over the course of 8-10 measurements. So there is a difference in the two pistons. It would seem that the DR piston sits higher in the cylinder than the LS. However this does not take into account of whether the piston pins in both sit at the same level in the cylinder. I found some parts and put a stock piston on a bottom end and a cylinder. At TDC the distance from top of piston to top of cylinder is 5/32", measured roughly with a small metal machinist rule with a stop. Does anyone have a DR engine handy ? |
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Title: Re: Cylinder Head Baseline Data Post by batman on 12/06/18 at 20:05:25 Lancer, The timing is retarded as the chain stretches, It is also retarded if you shave the cylinder or the head. when you shaved both .040 ,you moved the drive shaft and the cam shaft .040 closer to each other introducing .040 slack in each side of the cam chain ,for a total of .080 .where does it end up? The front of the chain is pulled tight as the cam is driven ,but is .040 shorter ,the chain is not ,and is .080 longer than it needs to be. All that slack is taken up by the cam chain adjuster and guide on the rear ,which causes the cam to rotate backward and be retarded. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 12/07/18 at 00:11:47 Let’s focus on the things we know, and see what we can figure out from them. Dave reported a 195 psi compression pressure with a Wiseco 95mm and a stage 1 cam. The stage 1 has an intake closing point of 40 degrees ABDC @ .050” lift. The 95mm bore is 3.740”. The 94mm stroke is 3.700”. I reported a 155 psi compression pressure with a completely stock engine and a little over 1000 miles. The stock engine has an intake closing point of 40 degrees ABDC @ .050” lift. The stock 94mm bore is 3.700”. The stock 94 mm stroke is 3.700”. The stock combustion chamber volume is 57cc. The stock head gasket is .026” thick (I measured with micrometer). That works out to 4.7 cc. The 5/32” negative deck reading Lancer took is very much appreciated. It proves without doubt that there isn’t sufficient quench clearance to support ideal combustion. At .156” its way too big. It needs to be .040”. Dave & Fast650 provided some rod length data, and its approximately 6.535” from the centerline of the gudgeon pin to the centerline of the wrist pin. Regarding the compression height (vertical centerline of wrist pin to top of piston). The value Wiseco gave to Lancer is correct. I measured a new Wiseco at 1.123”. That’s close enough to the 1.128” that Wiseco provided. The measurement Lancer provided for the LS piston (16.6 mm) works out to a compression height of 1.107”, so the LS piston is about .016” shorter. That’s a lot of information to work with. If we plug some of it into the RB Racing Compression Calculator and fiddle around with it, we can get some really valuable info. All the calculations assume zero boost pressure and 500 feet elevation. If I'm off a bit on the elevation it shouldn't be too big of an error. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 12/07/18 at 00:13:24 First, confirm that the calculator works. Using the stock data, run the calculation and see what the predicted cranking pressure should be. Bore 3.700” (94mm), stroke 3.700” (94mm), rod length 6.535”, static compression ratio 8.5:1 (as advertised), intake closes 40 degrees ABDC. The calculator indicates that cranking pressure should be 152.6 psi. I got 155. Close enough for me. The calculator indicates that the combustion chamber is 86.92 cc. Since we know that the chamber in the head is 57 cc, the remaining volume (86.9 – 57 = 29.9) must be the combined volume of the gasket and negative deck. The gasket is 4.7cc so that leaves 25.2. The negative deck volume should be around 25 cc. A cylinder 5/32” tall by 3.7” diameter has a volume of 1.68 inches squared (27.5 cc). So, we are within 2.5cc. That’s pretty close. I say the calculator works. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 12/07/18 at 00:14:19 Now, let’s use Dave’s numbers to estimate what the actual Wiseco compression ratio is. You can do this by simply repeating the calculations using different compression ratios until you get a cranking pressure around 195 psi. Using the following data, I got 195 psi cranking pressure. Bore 3.740” (95mm), stroke 3.700” (94 mm), rod length 6.535”, static compression ratio 10.3:1, intake closes 40 degrees ABDC, boost 0, elevation 500 feet above sea level. So the 95mm Wiseco results in a static compression ratio of 10.3:1. I think that’s high enough. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 12/07/18 at 00:16:18 We can use the calculator to predict what the compression ratio will be with a flat top piston, .040” quench clearance, and stock bore. Do this by using the known combustion chamber volume, which will be 57cc plus the volume of a .040” thick head gasket. The gasket has a volume of 7.2 cc, so the chamber volume with a zero-deck setup will be 57 + 7.2 = 64.2cc. Simply run the calculator using different compression ratios until you end up with a chamber volume close to 64cc. That turns out to be a compression ratio of 11.2:1. So if you can set up your engine with a flat-top piston, zero deck, and a .040” head gasket, you will end up with about 11.2:1 static compression ratio. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 12/07/18 at 00:20:25 I personally feel that anything over 10:1 is too high for a street application. Pump gas is pretty sketchy, with 93 octane about the best available. Over here 92 is the best you will find. We can’t do much with ignition timing, and the bore is large. I know the spark plug is centrally located, but the bore is very large, and its air cooled. I wouldn’t advocate running much over 10:1, unless you can find a cam that closes the intake at 50 or more ABDC. Dave’s engine has slightly more displacement than a stock engine. That results in a tiny bit more static compression. A stock bore will probably come in a bit lower, like maybe 10.1:1. That looks OK. It looks to me like the cat’s meow would be to relieve the top of a flat top piston about 6 or 7cc. You could do that by cutting valve reliefs or possibly machining a small depression in the top equal to 7cc, leave a nice wide band around the circumference to generate the quench. That way, you would end up with around 10:1 static compression (relatively safe), maintain a quench clearance of .040”, and keep the combustion chamber wide open for flame travel. To accomplish this, you need a piston with a compression height about 5/32” greater than stock. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 12/07/18 at 00:22:59 If you try to reduce the deck height by machining the bottom of the cylinder, the cam chain will go slack. Taking .156” off the bottom will result in .312” additional slack on the chain. Don’t worry about cam timing, that can be adjusted. The slack chain is the real problem, it will result in failure. It is conceivable that a chain with one less link could be used to compensate, but that would make the chain about .50” shorter, and we only have to take up .31” slack, so now it might end up too tight. That looks sketchy. I like the flat-top piston with taller compression height and top relieved 6 or 7cc. It's got it all. |
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Title: Re: Cylinder Head Baseline Data Post by Armen on 12/07/18 at 03:07:36 By moving the crank sprocket on the crank one spline, and the chain on the sprocket one tooth in the other direction, minor changes in timing are possible. Looking at how stretched some of the cam chains are (pics posted on the forum), people using the modified tensioner are getting away with some really stretched out chains and really extended tensioners. Maybe the extended tensioner and a new chain would be enough to make up for the additional slack created by cutting the cylinder down? |
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Title: Re: Cylinder Head Baseline Data Post by LANCER on 12/07/18 at 03:35:02 494A5F464A451F132B0 wrote:
The head/ cylinder mod’s I did were to shave the head .015” and the cylinder .025” for a total of .040, it was not .040” each side. Just a note. Thank you for your knowledge and notable input. My engine math skills needs to be upgraded, that’s for sure. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 12/07/18 at 12:05:46 Armen, it's a thing of beauty. Indexing the drive gear to advance and retard cam timing is so cool. So, if you achieve a 2.583 degree change by moving the chain one-tooth and the spline one-tooth, wouldn't you achieve a 5.166 degree change by moving the chain two teeth and the spline two-teeth? And couldn't you go either direction, advance or retard. Sounds like it's pretty adjustable. Lancer my man, you are the test bed. You lobbed material off the head and cylinder so you have intimate knowledge regarding the effect on cam chain tension. What can you tell us about your real life experience with the chain after removing a total of .040" from the total height? How much looser did the chain become? How close did the slack side get to the drive side after the head & cylinder were shaved? In your opinion, do you feel the system is forgiving enough to remove around .124" from the underside of the cylinder. That's about 3 times more than you removed. For example, the head gasket is .026" thick. We want .040" quench, so we should shoot for .014" negative deck height. If we achieved .014" negative deck, the result would be .040" quench (.026" gasket + .014" negative deck = .040" quench). The Wiseco piston has a compression height that is about .016 to .021" greater than stock and the stock negative deck is 5/32" (.156"). With a Wiseco installed the negative deck would be reduced .016" to .021" (mid point about .018"). So just installing the Wiseco gets us to about .138" negative deck (.156" - .018" = .138"), and we want .014" negative deck. So to achieve .014" negative deck, we need to shave the cylinder base .124". |
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Title: Re: Cylinder Head Baseline Data Post by batman on 12/07/18 at 14:55:55 Lancer ,Yes you shaved .040 off, but the cam chain has two sides which means you introduced .040 slack in Each side of the chain! when you run the motor the front side of the chain is under tension driving the cam ,that shifts all of the slack to the rear side and All .080 of slack is then taken up by the cam tensioner . pretend for a minute that the drive gear on the crank shaft is fixed (the spring pressure of the tensioner not being strong enough to move the heavy crank ,rod and piston) then when you install the tensioner only the cam can move .It will be rotated backward to take the slack out of the front section of the chain (which is normal when the bike runs) .040 & .040 =.080 the total amount of slack in the chain, All of which is taken up on the backside of the chain by the tensioner ,and the .040 that was in the front section is now gone by way of the cam rotating backward , that .040, which retards the cam timing.I can't explain it any better ,sorry. |
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Title: Re: Cylinder Head Baseline Data Post by verslagen1 on 12/07/18 at 18:09:34 Shave .040" from the head/cylinder interface is basically the same as .080" chain stretch. At .03" chain stretch, you have about 18mm plunger projection. At .08", you probably needed the second hole on the verslavy and were near the end of travel. |
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Title: Re: Cylinder Head Baseline Data Post by batman on 01/21/19 at 18:42:34 [quote author=686E611D1F181C2C0 link=1542776128/0#0 date=1542776128 ] ..........." Therefore, power is limited by the amount of air introduced into the cylinder." -- and in the case of our bikes air in , is even more limited by the amount of exhaust gases we can expel from the cylinder at higher(past peak torque) rpm's . Increase volumetric efficiency(VE) , and the amount of fuel/ air drawn into the cylinder and the power made will automatically increase. Of course with our exhaust passage this may be easier said than done. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 01/26/19 at 19:16:22 I recently finished flow testing two cylinder heads. One of them is a severely damaged head that I intend to use as a test mule, and the other is my good head that is in pristine condition. Since this post was originally intended to capture baseline data on the LS650 cylinder head, it seems appropriate that I post the flow test results here. I also will be posting the data to my post in the tech section along with information on the budget flow bench. The following graphs provide the flow data for the intake and exhaust ports on the pristine head, however, both heads flowed about the same. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 01/26/19 at 19:17:12 Here is the graph of the exhaust port. |
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Title: Re: Cylinder Head Baseline Data Post by DragBikeMike on 01/26/19 at 19:22:58 Looks like our stock heads flow about 150 CFM intake and 93 CFM exhaust corrected to 10" H2O. The flow bias is about 62%. These numbers aren't perfect as my budget bench isn't calibrated, but it does treat all test specimens equally so it's a good tool to measure improvements. I imagine the little contraption isn't too far off. Check out the update in the tech section to get the specifics on the changes to the bench and the test procedures. |
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Title: Re: Cylinder Head Baseline Data Post by batman on 01/27/19 at 21:18:38 Mike , nice job, and the results I would've expected .like the flows decreasing at valve lifts of .330 and .300 . |
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