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SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Big Cam - Web 340b Install /cgi-bin/YaBB.pl?num=1576548823 Message started by DragBikeMike on 12/16/19 at 18:13:34 |
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Title: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:13:34 In my never-ending search for more power, it was time to explore the merits of a big cam. Not a bolt-in cam with a bit more duration & lift, but a true big cam. A cam that would bring out the best in my hotrod. An aggressive cam will complement the other modifications and help them all work together. The ported head, bigger carburetor, free flowing airbox and exhaust, and higher compression were all yearning for a bump-stick with some decent lift & duration. The only candidates that I could find were the Web 420 grind and the Web 340b grind. Both cams are intended for use in the early DR650. This post will take you through my installation of the Web 340b. It is the hotter of the two cams. I figured if I was gonna go through all the trouble to set up a big cam, I might as well go for the gold. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:14:41 This is a shot of the stock cam and the 340b side by side. You can see that the basic cores are identical. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:15:21 If you compare the lobes you will note a pretty big difference. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:16:45 The 340b has more lift and aggressive ramps. You must run stiffer springs with more travel. This is the spring kit Web recommends for the DR650. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:17:46 The spring kit is manufactured by RD Valve Springs. Stock is on the left, RD is on the right. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:18:40 The RD retainers are titanium, and a lot different dimensionally. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:19:32 The RD retainers are designed for the DR650 valves. They won’t work on the LS. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:21:56 The RD cotters are also a lot different. I tried using the stock cotters with the RD retainers. The angle is different, so the stock cotters won’t work with the RD retainers. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:23:02 I decided to use the stock spring retainers with the RD springs. I contacted RD Valve Springs to see if the springs can be purchased separately. The spring part number is 1010 and they will set you back $38 bucks a copy for a total of $152. You can order them direct from RD Valve Springs (760) 948-4698. Website is www.rdvalvespring.com. Good guys BTW. They get right back to you. I might also mention that the finish on their spring is much better than the stockers. End grinds are nice & square and spring pressure vs lift was consistent on all four assemblies. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:23:56 The 340b cam has .417” advertised lift. The stock springs start coil binding at .400”. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:25:17 This shows the RD spring assembly at .450” lift. Plenty of room left on this one. Good to go. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:26:14 Here is a graph that compares the RD spring force to the stock spring force. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:27:38 The valve guides must be shortened to accommodate the additional valve lift. I made a tool. It’s a simple design that uses 1/8” HSS tool bits. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:28:26 Takes about one-hour to do all four guides. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:29:41 The finished product at the top of the photo. This was a test cut on a junk head. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:32:30 Then I added a chamfer. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:33:45 You must check valve to piston clearance to make sure the valves don’t contact the piston as it travels through TDC on overlap. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:34:33 With cam timing set at the factory marks, my intake valves got close to the piston. It would probably have been OK, but retarding cam timing improved the condition. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:35:17 The exhaust valves had plenty of room. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:36:17 The drive sprocket on the crankshaft ended up three splines counterclockwise from the factory mark. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:37:12 The cam timing marks looked like this when the cam timing was retarded 5°. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:38:04 It’s a little easier to see approximately how far the factory marks are out-of-alignment if you lay a six-inch scale across the head sealing surface. With timing retarded 5°, it looks like this. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:39:07 With cam timing retarded 5°, I checked the timing points (@ .050” valve lift) using a degree wheel and dial indicator. I have no way to know what the optimum cam timing should be because this cam is designed for a completely different engine. I felt 5° retarded from the factory timing mark was a good place to start on my engine, and the valve timing points seemed reasonable. I wanted a late closing intake to mitigate my high cranking pressure (245 psi). I’m hopin to get off the octane booster. Intake opens: 15°BTC Intake closes: 55°ABC Exhaust opens: 48°BTC Exhaust closes: 18°ATC |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:40:13 To improve oiling to the left side of the intake rocker shaft, I drilled a small hole in the left cam bearing pocket to admit oil into the adjacent head-cover bolt-hole. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:41:17 The new drilled-hole diverts oil into the bolt-hole and should fill this void adjacent to the rocker shaft. Hopefully I don’t end up with leaks. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:42:06 To provide a little additional oil to the rocker arms and shafts, I chamfered the stock oil holes. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:43:15 And I used a Dremel to grind a small oiling slot into the left hand thrust face of each rocker arm. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:44:15 I drilled the 340b cam lobes just like the stock LS cam. Dave did a great post awhile back that gives all the info on drilling these holes. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:45:20 I installed the RD valve springs with the stock retainers and cotters. Massaged a liberal coating of assembly lube into each spring. |
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Title: Re: Big Cam - Web 340b Install Post by Armen on 12/16/19 at 18:46:15 Awesome! Thanks! |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:46:22 Web supplies break-in lube for the cam. It looks like jelly. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:47:28 I applied a very thin coat of sealant on the head cover. It’s very important to keep the sealant away from the cam bearings. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:48:32 I use this tool to roll on the sealant, just like a paint roller. It works great. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:49:33 The sealant squeeze-out was very small, just the way it should be. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:50:45 For break-in, Web recommends 30 weight petroleum oil. I can’t find that stuff here in the islands. I had to settle on Castrol GTX 20W-50 motorcycle oil rated SG. I’m good with that. It’s for motorcycles, it’s for air-cooled engines, it’s OK for wet clutches, it’s rated SG (plenty zinc), and it’s dino oil. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:54:50 After the engine was buttoned up and reinstalled in the motorcycle, it was time to check compression. Prior to the cam installation, my cranking pressure was 245 psi. Too high. I would prefer 190 psi, the safe limit for 92 octane pump gas. One reason I installed the bigger cam was to lower the cranking pressure. The later closing intake valve should reduce dynamic compression. With the cam retarded 5°, the intake valve closes even later. My cranking pressure came in at 220 psi. Still not where I want it, but certainly better. It was time to see how it runs. It fired right up and settled in to a nice 1500 rpm idle. I didn’t even adjust the carburetor. Oil pressure seemed about the same as it was before the mods. It ran fine, low end torque felt about the same. It made a bit more tappet clickity-clack. No loud clunks, clanks or screeches. No sudden stoppage. Things were lookin rosy. After a very conservative 250-mile break-in, it was time to take a look at things. I checked the valve lash and did a visual inspection of the cam lobes. The intake valves were still about .004”, the exhaust valves needed adjustment. Cam lobes looked good. I removed the plug over the intake rocker arm shaft to see if the void was getting any oil. There was a nice puddle in the bottom of the void. I think that’s better. The oil should wick along the shaft to provide a little lubrication on the left side, which by design has little or no splash lube. Bonus! No leaks. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:57:07 How does it run? Street manners are pretty good. It starts right up. I think it starts better. Initially, I thought the fuel mileage was way off, but after living with it for a while I really don’t see much of an increase in fuel consumption. Throttle response is good, and low speed torque is just fine. The low speed torque seems a little less than what I had with the stock DR cam but still ample. It has excellent low speed performance. On the freeway, it has superb acceleration. Screw it on at 70 mph and acceleration is brisk, a real arm stretcher. Very easy to merge or to pass a big rig. That also holds true for country two-lane roads. You can get around slower vehicles with confidence. I evaluate my performance mods using a GoPro camera and stopwatch. I record my 2nd gear 4K to 7K time and then review the video with stopwatch in hand. Prior to installing the 340b cam, my 4K to 7K time was right at 2.90 seconds. With the 340b, the 4K to 7K is slightly slower, about 2.95 seconds. But the power band is now extended all the way to 8K. I haven’t tried taking it past 8K, that’s the limit on my tach. Comparing the 5K to 7.5K times shows the 340b is slightly faster at 2.88 seconds vs 2.95 seconds for the stock DR cam. That makes sense. So, with the cam retarded 5° from the factory marks, and no other tuning, it pretty much runs with the stock DR650 cam up to 7K, and then continues to pull strong past 7K all the way to 8K. I’m using 92 octane pump gas with no octane booster. I haven’t tried any jetting or ignition timing changes. It runs well, but to be honest I anticipated a big bump in steam. I suspect that the 4K to 7K time would improve somewhat if I advanced the cam timing back to the factory marks. That will close the intake valve sooner and increase my cranking pressure. It might put me back on the octane booster. I plan to try it to see what happens. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 18:58:54 I also think I might be reaching the limit of the stock airbox filter. The filter only has a 25 square inch footprint. That’s small. I might be able to squeeze a bit more out of the engine with a larger filter. My modified stock muffler could be holding things back too. I’ve done just about all I can to the muffler without turning it into a knarly, obnoxious beast. The current modified airbox and muffler are still quiet, just a bit noisier than stock. I don’t attract attention and my neighbors aren’t hatin me. A few weeks back one neighbor even commended me for keepin it quiet. Neighborhood harmony, ain’t it sweet! Looks to me like there’s not a lot more to be had through improved volumetric efficiency unless I go to the dark side and start making a lot of noise. My compression is at the limit and I don’t think there’s much more I can do to the induction and exhaust. I plan to try a modification to the airbox that will permit using a cylindrical filter with about a 55 square inch footprint, but I’m sure that will amp up the noise. From this point on, my horsepower options seem limited. I could try installing larger valves and take my cylinder head to Stage III, but the muffler and airbox might prevent the larger valves from doing their intended job. Increasing displacement is an option with proven potential. Adding 50 cubic centimeters should improve the low end. It already has superb low end so I think more displacement would be be a lot of fun. Decisions, decisions. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/16/19 at 19:03:00 If you’re lookin for a new cam, the Web 340b is a viable candidate, but you will have to tear the engine down to install it. I also think that life expectancy will be significantly reduced. The heavy springs combined with my natural inclination to take the tach past 7K will certainly take their toll. But hey, it’s a hotrod. I’ll do periodic posts to let you know how it holds up. For the average Savage rider, I don’t think this 340b cam offers anything over the stock DR650 camshaft (at least when the 340b is retarded 5°). The stock DR cam is a bolt-in cam and doesn’t require changing springs or shortening guides. You can bolt it into a stock engine, plug & play. But my project is a never-ending search for more power. That mandates that I keep trying new things. So, the 340b is a good addition for me, but not for everyone. For now, it’s got me off the octane booster, and the bike is running great, and I think it will respond well to some tuning. As always, thanks to the Fastman for help & advice. Also, a shout out to Batman for bringing up the rocker arm oiling issue. I don't think I would have looked at the rocker oiling if he hadn't brought it to my attention. Knowledge is power. |
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Title: Re: Big Cam - Web 340b Install Post by Gary_in_NJ on 12/17/19 at 07:19:10 As usual, a thread with an incredible journey and conclusion. Thanks for the write-up. |
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Title: Re: Big Cam - Web 340b Install Post by ohiomoto on 12/17/19 at 12:22:52 Wow! My jaw drops whenever I read a DBM experiment. Impressive work. |
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Title: Re: Big Cam - Web 340b Install Post by Dennisgb on 12/17/19 at 12:36:58 This is really interesting. Being new to the 650, are there links to info on installing a stock DR650 cam? |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/17/19 at 22:07:44 Mahalo Gary & Ohio. Dennis, I'm sorry, I don't have a link to a detailed guide for installation of the stock DR650 cam. I do have a link to a report I did awhile back. It has a few tips that might be useful. The stock DR650 cam is a bargain and I found it to be a pretty good bumpstick. It's easy to install. If you've got some basic mechanical skills and a manual you shouldn't have any trouble. http://suzukisavage.com/cgi-bin/YaBB.pl?num=1525327311 |
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Title: Re: Big Cam - Web 340b Install Post by Dennisgb on 12/18/19 at 07:08:03 40464935373034040 wrote:
I found your thread earlier. Good stuff. I’ve been building and restoring bikes for 50+ years so no problem doing the cam change. I really was more interested in the performance which you outlined pretty well. It’s interesting to me that the Savage S40 is around 30HP and the DR is mid 40’s. Wondering what the HP boost would be with the DR cam and stage one mods. I’m planning to do the standard performance mods and a Mikuni flat slide carb. Thinking it should gain a few HP. I’ve found the flat slide carbs to be much more responsive than the round ones in other bikes I’ve upgraded BTW. |
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Title: Re: Big Cam - Web 340b Install Post by Gary_in_NJ on 12/18/19 at 08:16:37 47464D4D4A504441230 wrote:
There are some big differences between the DR & LS. First off, Suzuki intentionally restricted air flow through the LS engine via an exhaust divider/restriction. Secondly, the DR cams and valve springs allow for a higher redline. A lot of power is made in those extra ~1,000 rpm. Getting your horsepower into the upper 30's is mostly a bolt-on endeavor. A high compression piston, cams and a good porting will get you to the upper 30's. Getting your horsepower above 40 takes great attention to detail and know-how (thanks to the forum engine builders for sharing). |
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Title: Re: Big Cam - Web 340b Install Post by Fast 650 on 12/18/19 at 10:36:22 Just a good port job, cam, and less restrictive exhaust and intake will put you in the very high 30's at the wheel. The LS650 suffers from a bad case of asthma, anything that you can do to improve the breathing (especially the exhaust) will reap big improvements in power. |
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Title: Re: Big Cam - Web 340b Install Post by Dennisgb on 12/18/19 at 10:59:57 373D39333831353C626460500 wrote:
That’s a pretty good boost for not a lot of upgrades. Do I really need a high compression piston to run the DR cam? |
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Title: Re: Big Cam - Web 340b Install Post by Dennisgb on 12/18/19 at 11:00:24 4C6B797E3C3F3A0A0 wrote:
Thank you. |
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Title: Re: Big Cam - Web 340b Install Post by Fast 650 on 12/18/19 at 11:25:16 Dennisgb, check out DragBikeMike's thread on porting the head, here is a ton of good information in that thread. And there are gains to be had from improving the airbox and filter. On the exhaust side of things, a better flowing muffler and larger inside diameter pipe will make a world of difference too. Go for the easy and cheap mods first, the ones that give the most bang for the buck. If you decide that you want more power, like a bigger bore, you have already taken care of those things that would need to be done to get the most out of that anyway. |
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Title: Re: Big Cam - Web 340b Install Post by Dennisgb on 12/18/19 at 11:29:19 5B7C6E692B282D1D0 wrote:
I have a Dyna Exhaust and plan to do carb and air box upgrades. Were can I get a larger ID pipe. I’ve searched around and can’t seem to find them. |
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Title: Re: Big Cam - Web 340b Install Post by Fast 650 on 12/18/19 at 11:42:18 4A4B4040475D494C2E0 wrote:
There are a few aftermarket companies like MAC that make larger pipes. Or you can hit an exhaust shop and have them make you a new pipe if they have a tubing bender. Another option is buy pre-bent stainless tubing from Summit Racing or JEGS and cut and weld a new pipe. For a stock or mild engine, 1.5" ID is a good size. If you are getting more serious go for 1.625" ID pipe. 1.625" ID will be 1.75" OD which will fit your Dyna perfectly so you may want to go with that size anyway. |
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Title: Re: Big Cam - Web 340b Install Post by Dennisgb on 12/18/19 at 11:50:11 4D6A787F3D3E3B0B0 wrote:
Thanks. What’s the stock pipe ID? |
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Title: Re: Big Cam - Web 340b Install Post by Fast 650 on 12/18/19 at 12:06:15 The stock pipe is a lie, that big 2 inch pipe has a tiny pipe inside, only about 1.3" ID. Way to small for a 650 to be able to breathe. |
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Title: Re: Big Cam - Web 340b Install Post by Dennisgb on 12/18/19 at 16:33:19 02253730727174440 wrote:
Thanks again |
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Title: Re: Big Cam - Web 340b Install Post by Matchless G11 on 12/19/19 at 02:58:21 092E3C3B797A7F4F0 wrote:
There are a few aftermarket companies like MAC that make larger pipes. Or you can hit an exhaust shop and have them make you a new pipe if they have a tubing bender. Another option is buy pre-bent stainless tubing from Summit Racing or JEGS and cut and weld a new pipe. For a stock or mild engine, 1.5" ID is a good size. If you are getting more serious go for 1.625" ID pipe. 1.625" ID will be 1.75" OD which will fit your Dyna perfectly so you may want to go with that size anyway. [/quote] I know there is may be a loss of torque going to a larger diameter pipe. Has some one like drag bike mike done a comparison from the 1.5 vs 1.625 pipes? |
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Title: Re: Big Cam - Web 340b Install Post by Fast 650 on 12/19/19 at 07:58:15 253C3232646427302130363E666160550 wrote:
I don't think anyone has tested 1.5 and 1.625 pipes back to back, but it shouldn't have a noticeable effect on low end torque. The available cams don't have enough overlap for pipe diameter to hurt the torque enough to feel it. DBM is running a big 1.79" ID pipe and it hasn't had a negative effect on low speed power. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/31/19 at 00:12:32 That big MAC header doesn't seem to be hurting the low end with the 340b cam either. The 340b does have a lot of overlap and the 1.79" header is working fine. Wish I had a nice 1.62" ID header to do a comparison. I think the 1.62" would probably work a bit better. I could use the poor man's dyno to test it. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/31/19 at 00:14:55 After logging another 300 miles on the 340b cam it was time for another inspection. It has now spent a good bit of time in excess of 7500 rpm. Nothing has exploded. There are no horrific noises drifting out of the engine. There or no leaks, weeps or seeps, it’s oil-tight. The valve clearance is still right about .004” on all four valves (that’s a good sign). Visual inspection of the cam lobes shows no indication of scoring. The surfaces surrounding the drilled holes look fine, and the noses on the lobes also look fine. All four valve spring retainers look good, there’s no indication that the retainers are shifting on the springs. Everything under the valve covers looks to be normal. The heavy-pressure RD springs aren’t causing any distress yet. After a bit of tuning I was able to get the 4K to 7K time down to 2.85 seconds. That was about as good as I could get it. The 92-octane pump gas is working out great. Not a hint of detonation. Plug check looked fine. Porcelain had just a hint of grey, electrodes were clean, no black specks or metal balls. I decided to try the larger air filter. The K&N cylindrical filter element (RD-0710) is 3.5” x 5”. That’s a little over two-times more filter area than stock. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/31/19 at 00:18:14 The larger filter had a huge effect. It was very difficult to get the thing to run correctly. I spent a very long time grooming the S&S carb with the stock replacement K&N flat-panel filter, and it wasn’t easy. So, I figured that with a bit of effort I should be able to dial it in. Lot’s of luck with that. This tuning job was a real handful. :o I could tell right away that the thing made a whole bunch more power, but it ran terrible. Waaaaay too lean at first. I started with a #60 main jet and ended up with a #68. The pilot jet and the two air-bleeds were all over the place. Get it cleaned up down low and it wouldn’t run up top. Get the top squared away and you could hardly ride the thing on surface streets. The accelerator pump was also a headache. I eventually got the thing pretty close, but a lot rougher around the edges than it was before the filter mod. The WOT performance is absolutely killer. It runs from 4K to 7K in 2.65 seconds, and it’s scary how quick it blows past 8K . Glad those RD springs are in there. Loads & loads of mid-range torque. Starts great. Idles good. Part throttle operation is acceptable but it ain’t gonna win any awards in the “seamlessly smooth” category. I was truly amazed at how much the filter affected performance. It begs the question; how well would the stock DR cam have run with this filter? I plan to do a separate post on the filter setup. Seems to me that it has the potential to make significantly more horsepower, regardless of the carburetor. I also suspect that a more forgiving mixer like the stock Mikuni or a VM would not present such difficult tuning issues. So, the 340b cam with RD valve springs seems to be hackin it. Oh! BTW, it’s loud. :-X |
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Title: Re: Big Cam - Web 340b Install Post by LANCER on 12/31/19 at 09:15:23 [ch128514]. It winds up to 8k in a flash doesn’t it ? 2nd gear wide open from 4-7k takes about 1.5 blinks in time on mine ... or something like that. Just wait until you get your setup humming. There is more grunt available. Going to a smaller header should solve a lot of your tuning issues and you may find the elusive power you mentioned seeing. Your symptoms sound like a bike running a straight pipe, or one too large. Consider: 1.5” ID pipe should be good for a 35-50 hp cylinder 1.63”ID pipe ... 45-63 hp/cylinder 1.75”ID pipe ... 60-73 hp/cylinder (Tube info from “Headers by Ed” doc) I did have opportunity to test a MAC header with a 1.65” ID header side by side. My personal experience was that the 1.75”ID MAC was a detriment to my bikes performance. Increase in cross sectional area as ID increases: 1.5-1.65. 17% 1.65-1.75. 15.7% Air velocity is lost in the header as tube diameter increases. Going from 1.75” down to 1.5” would decrease tube volume almost 35.4%. Velocity goes up as well as efficiency. With the increase you found by changing the intake overall efficiency improves even more. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 12/31/19 at 10:48:33 Excellent observation Lancer. The large header diameter certainly doesn't help, and link that up with the increased overlap and I have a recipe for pretty cobby low-speed ops. It doesn't explain why the carburetion was pretty good with the old air filter setup. If the header pipe was upsetting the applecart I would think that the header wouldn't care what air filter was in place. I admit that I am flummoxed at this point. The custom header is hard to come by out here. I guess one diagnostic measure I could try is to install the stock header. If that cleaned up all the low speed shenanigans I would then have some concrete evidence that the header is an issue. It just doesn't behave like it's the header. It's really good everywhere except very light load. Open the throttle just a bit, just ever so slightly, and BAM! As soon as you move the throttle just a little more open it just cranks, very torquey. I've thrown a leg over a lot of Harleys with drag pipes. This thing doesn't behave anything like a bike with straight pipes. The classic surging and hesitation in mid-range is not there. The reluctance to take more throttle is not there. It misbehaves when the throttle plate is positioned right in the area where the transition ports are located. It did a little of that when I had the small filter installed, but with careful jetting I eliminated the issue. Installed the bigger filter and I can't seem to tune-out the problem. It's still so darned much fun to ride that I ain't even considering goin back to that small filter. Once again, excellent observation. You have given me some ideas for diagnostic tests that might shed some light on things. |
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Title: Re: Big Cam - Web 340b Install Post by batman on 12/31/19 at 11:01:27 DBM, you might try turning the elbow 90 degrees , that might help balance the air flow through the throttle plate , top to bottom, as the flow tends to hug the outside curve of the 90 and the roof of the intake passage , more so at lower throttle setting when intake velocity is lower and atomization of the fuel on the short turn is much lower ? That or adding a straight section of intake between the filter and carb ,either might allow easier jetting /smoother running lower speeds? |
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Title: Re: Big Cam - Web 340b Install Post by Fast 650 on 12/31/19 at 11:55:40 As I understand it, he has that mounted inside the airbox and still has that straight section from the airbox to the carb. So there must be something else at play here. |
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Title: Re: Big Cam - Web 340b Install Post by batman on 01/01/20 at 13:15:26 The air mass inside the intake pipe , may be slow to accelerate ,if the pipe is oversized . Use of a smaller pipe should increase velocity at lower throttle openings , that may be causing a lean condition , but may limit performance at higher rpms , but if DBM is turning rpms over 8000, he may well be able to except that loss to have a smoother running motor. |
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Title: Re: Big Cam - Web 340b Install Post by LANCER on 01/02/20 at 07:51:34 06000F73717672420 wrote:
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 01/02/20 at 10:24:59 Batman, the Fastman is correct. The new filter is located in the airbox. The flow path is similar to the stock airbox setup. Air enters the filter element, turns vertical and moves up through a 2 inch 90 degree elbow, then flows horizontal straight through a 2 inch hose into the carburetor. The flow path is almost identical to the stock airbox except it's smoother, no ridges, ledges, edges, etc. The idle mixture port and transition ports are in the top of the carburetor bore, just like the stock carburetor. That would confine the air mass to the side of the butterfly where the idle mixture and transition ports are located during high-flow conditions (WOT). At low flow conditions, the air mass is sort of piling up against the throttle plate. I don't see it being much different than the stock geometry, but who knows? Lancer I know my pipe is less than ideal and a 1.62" would be better, but out here in the middle of the ocean, custom exhaust headers are few and far between. I have some plans for diagnostic testing that should help me narrow the problem down. Would you agree that if I installed the stock header and the light-load issue went away then its a pretty clear indication that the exhaust pipe might be my problem?....or.....If I installed the stock carburetor and the light-load issue went away, wouldn't that indicate that the S&S carburetor might be my issue?....or....If I installed a carburetor more suited to a single-cylinder engine (like a VM) and the light-load issue went away, wouldn't that tell us something? Regarding your questions about RPM and throttle position. It seems to be more load dependent than rpm dependent. It only occurs when the load is extremely light. It's most pronounced on the freeway, where you can get the thing into a situation where you are running completely steady-state at extremely small throttle opening. Couldn't pick a more irritating condition. The AlF goes waaaaaay lean. Open the throttle just a hair and start to load the engine and the mixture returns to 11-12 and away you go. Put any load on it at all and the issue clears right up. It's right where the throttle plate is sweeping across the transition ports. Go WOT from any speed or rpm and it pulls great, clean, nice & rich, all the way to 8K+. For now, I'm staying away from the diagnostic header change. The way I have my exhaust set up it's a royal pain to separate the header from the muffler, so I want to try some other stuff first. This is a good exercise. Frustrating but very interesting. I appreciate all the comments. Knowledge is power. Stay tuned. :P |
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Title: Re: Big Cam - Web 340b Install Post by batman on 01/03/20 at 09:37:24 DBM , I will assume when you say 2 inch 90 and hose that we are talking outside diameter ,that seems OK , but you're now entering the realm of intake tuning, where the length of the intake from the intake valve to the mouth of the filter has influence on boost . You may want to look into that . the other thing is the fact that you altered the intake channel inside the head to increase velocity ,that's a good thing ,but in doing so the filler you used appeared to be very smooth on the short side tunnel and turn, not the best thing when you're just starting to crack open the throttle plate as the fuel doesn't have a good chance to atomize into small enough size to mix with the air ,but tends to run down the short side as large particles and not ignite in the cylinder . You may not be lean as much as less efficient , It may pay to install a few small grooves in that area ,hitting the grooves would tend to atomize the fuel as well as direct it toward the center of the intake passage where the velocity is the highest. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 01/04/20 at 12:22:38 The ID of the stock airbox nipple is 2.260". My 2" ABS elbow has an ID of 2.030" so its just a tad smaller than stock. My carburetor inlet has an ID of 2.190". I would prefer having a converging inlet track starting from about 2.5" at the airbox and reducing to 2.2" at the carb inlet, but you takes what you gets. The selection off the shelf at the hardware store is limited. I suspect my issue is more closely related to carburetor application. All along I knew that installing a fixed-venturi carburetor designed specifically for a large displacement V-Twin would be a challenge. I'm actually surprised that I got it as good as it is. I'll leave the intake tuning to the scientists but I'm sure it wouldn't hurt to study up a bit. :) Thanks for the suggestion. You got any links to reference material (not on the grooves but on the intake tuning)? |
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Title: Re: Big Cam - Web 340b Install Post by batman on 01/04/20 at 23:17:19 DBM , You might take a look at -racehead.com.au (performance) check out the, wave-pulse-rpm-chart.jpg it shows 2nd 3rd and 4th pressure waves of 10, 7,and,4% boosts , at rpms they can be converted to show speeds by dividing by 66.8 (for fifth gear ) if your final drive ratio is stock. Understand that these boosts are rpm related , and will occur in any gear . |
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Title: Re: Big Cam - Web 340b Install Post by batman on 01/05/20 at 11:31:58 Perhaps telling of my setup may give you a better idea of what can be done for intake tuning, my bike is stock except for a Dyna muffler and my tuned intake . I based my intake length on the rpms found for 17 inches. The actual length being 16 1/4 inches as the length of the intake needs to be shortened by 1/2 the diameter of the ID of the tube ( 1.57 inches in the case of my 2inch PVC s-40 pipe ) , as the pressure wave has to leave the end of the tube before it reverses and moves back into the tube toward the carb. based on this the numbers (ballpark) look like this ; start 4% boost 4048 rpm/61mph max ** 4308/64.5mph end 4527/68mph 7% boost 5192/78mph 5577/83.5mph 5934/89 mph *** 10% boost 6911/104mph 7682/115mph **** 8386/126mph( 8000/120mph) ** boost is not neck snapping it eases in and out ,peaking at the mid range *** the numbers are ball park , as my bike being stock , is only able to use the 3rd and 4th waves , but top speed is 90mph -real world speed (6012rpm) **** You should be able to use these numbers (2nd wave) the speeds shown are more the type you would see on a dyno , not on the road with rider weight and frontal area wind drag. your results my vary. The pressure waves could care less about the diameter of your pipe only it's length. But the pipe you use should be sized more toward the size of your throttle plate rather than the mouth of the carb ,ex; my cv carb throttle opening is about 1.5 inches in area . my PVC intake 1.57 inches in area. I believe what your using is to large and killing the velocity in your intake , it is better to error on the small side as you will see gains in the low to midrange rpms and only a slight loss at high rpms, if to large you won't see any gain across the whole rpm range. All rpms above are in 5th gear ,as you can see these match up fairly well with my intend highway speeds , If I need more speed say entering an expressway on ramp or passing leaving the bike in 4th gear or down shifting, will bring the boost on at lower speeds ex; 4th gear -7% boost - 5192/71 mph 5577/77.2mph 5934 /82mph 4th gear 71 to 82 5th gear 78 to 89 So traveling a 70mph needing to pass, would be a down shift to 4th and upshift to 5th @ about 80 to stay in the 7% area of boost from 71 to 89 mph . I estimate to achieve 90 mph top speed I need to produce somewhere between 33and 34 hP , about equal to a stock bike with a DR650 cam ,without having to buy or install one , and yes my tuned intake is also inside my stock air box, use of street elbow ,and short section of pipe allows me to retain the rubber tube between the box and carb , I moved my Oldfeller's style filters to the outside rear of the box, between the frame posts just in front of the rear fender , retaining the side covers and the bike appears completely stock . |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 01/06/20 at 13:03:38 Thanks for hooking me up with the website. It's interesting. With the S&S fixed venturi carburetor I would have a very difficult time achieving the geometry specified. The carb itself has dramatic converging/diverging geometry to create the venturi, and then I have to use a special converging manifold to adapt to the cylinder head. The website does offer these nuggets of golden info: “I have to point out here that its the runner size that's most significant and the ITB should be appropriately matched to the runner both before and after the actual butterfly plate.” As I mentioned, the fixed venturi carburetor and special manifold render this requirement close to unachievable in my situation. “This (runner too large) will affect the power at all rpm levels, the intake charge cant obtain enough velocity at peak torque rpm to fill the cylinder well so it will be boggy and unresponsive then as rpm rises and the efficiency of the engine falls and the cylinder still wont achieve the required velocities to pack the cylinder full with fresh intake charge during the valve opening period and the engine will never reach its full potential.” “On the other hand (runner too small) if the velocity is too high then the engine will make excellent torque and mid range power due to the high velocities but at some stage as the rpm rises the power level will be slightly less than the maximum potential due to flow loss known as choke.” With my current setup, the engine is not the least bit "boggy and unresponsive", and it is certainly not "choked". It has stellar toque throughout the entire power band, and it pulls strong well past 8K. It's nuts (in a good way). I just can't tune out this nasty little lean-surge right at the transition from intermediate jet to main jet. It's irritating, right where I want to cruise. Crack the throttle just a hair and it completely goes away and pulls nice & clean. I appreciate the link. I also have some good reference material in a book Rutly turned me on to; Four Stroke Performance Tuning. Once I get the carburetion sorted out I think I will try playing around with a slightly smaller intake run from the filter to the carburetor. |
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Title: Re: Big Cam - Web 340b Install Post by LANCER on 01/06/20 at 16:07:21 DBM, is your definition of “entire power band” based upon rpm or throttle position ? |
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Title: Re: Big Cam - Web 340b Install Post by batman on 01/06/20 at 20:06:35 DBM , I can understand you not changing your intake diameter but you could still try tuning it to length. You might even consider use of a Gadgetman Groove in the area where the carb is going lean. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 01/06/20 at 23:30:57 Lancer, my evaluation of the power band relates to engine rpm. If I open my throttle anywhere past 3000 this thing takes off, and just keeps accelerating hard all the way past 7000. It just seems to have killer torque everywhere. It runs just fine below 3000 too, but I'm very rarely in that rpm zone. I'm very surprised how broad the useable power is. I figured the long duration cam, with 5 degrees of timing pulled out, would make the thing a peaky. I'm OK with peaky if there's a huge kick to put a grin on my face. But this thing is as far from peaky as it gets. I have to assume it's the compression, but I also think that the epoxy buildup on the floor of the intake port has something to do with it. I think this big filter unleashed the beast and let the other components do their job. It just has this irritating little glitch right at the edge of the transition ports, right where my throttle plate lines up exactly with the 3rd port. It's drivin me nuts. :o Batman, before I start messing with intake tract tuning, I've got to figure out this little hicup. Every day I mess with it I become more convinced that its related to the application. That carb was specifically designed for a large displacement V-Twin. The transition ports are manifold vacuum dependent. They don't care about flow because they are well forward of the venturi. The big cam with retarded timing killed the little bit of manifold vacuum that this single-cylinder engine develops. I think I have met my Waterloo. |
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Title: Re: Big Cam - Web 340b Install Post by batman on 01/07/20 at 09:45:38 DBM ,I don't know what to say at this point, Can you reduce the amount of retardation in the cam without the valves striking the piston ,and increase the head displacement to deal with the higher compression? would that even help? Is the hiccup caused by exhaust reversion? |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 01/15/20 at 00:06:43 Sometimes it's the simple stuff. I installed the stock carburetor. Problem solved. No more irritating little glitch at light load. In the process of setting up the stock carb for the modified engine, I reviewed some articles on the Mikuni CV. I found a pretty good rundown from an outfit called Factory Pro. They use the float level to tune light load conditions. I found that interesting. Since it ran fine with the stock carburetor, I figured my problem must be the S&S carburetor. Its not the exhaust header or the new hi-flo air filter. That float level thing kept grinding at me. I checked the level several times. It was exactly on the S&S spec, but that spec is for a big V-twin. I'm runnin it on a 40 inch single. I readjusted the float level to 1/16" above the S&S spec. End of problem. Now it responded well to tuning and in no time flat it was runnin better than ever. 8-) I am amazed at how well the thing responded to such a minor adjustment. It makes perfect sense. The idle & transition circuits were designed for a much larger engine that pulls a lot more manifold vacuum. The little Savage mill with the big cam just didn't have the oomph to lift that fuel up into the low speed circuit when the throttle plate was in the final stage of transition. Raise the fuel level and it doesn't have to lift as far. If you are interested in a pretty good step-by-step for tuning the stock Mikuni CV, check out this Factory Pro link. It's got some good stuff in there. You learn something new every day. http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,CV,high_rpm_engines.html |
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Title: Re: Big Cam - Web 340b Install Post by Armen on 01/15/20 at 03:14:38 Excellent! |
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Title: Re: Big Cam - Web 340b Install Post by Armen on 01/16/20 at 15:56:10 Or, the hi flow filter offered less resistance, so there was less vacuum in the carb body. Years ago I had a 550 Honda in my Mcy maintenance class with a K+N filter and no airbox lid. Ran like crap. Covered half the hole that used to be the airbox lid with my hand and magically the bike revved clean. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 01/16/20 at 22:36:10 Just imagine how nice it would have run if you fattened up the mixture to accommodate the increased airflow instead of strangling the poor thing. :-X I believe you are absolutely right. That puny flat-panel K&N I was running was sort of acting a bit like a choke. Gave it just enough vacuum to pull the fuel through the slow speed circuit. Like I said, I ain't never goin back to that small filter. It ran good with the small filter, but the improvement with the big filter was so dramatic that there was no turnin back. I had to make that carb work right with the big filter. It was worth all the effort. 8-) |
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Title: Re: Big Cam - Web 340b Install Post by Armen on 01/17/20 at 04:33:46 Glad it worked out! So, on the 550, we did install larger jets. I was just trying to show the kiddies the effect of intake resistance on fuel pickup. Looking forward to another dyno run for your bike! |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 03/20/20 at 03:09:27 Time for an update. On SuperBowl Sunday I got careless with some testing and melted my piston. Runnin a little too lean. It had to come apart to repair the piston, so it gave me the opportunity to take a hard look at the cam, rockers, springs and retainers. Mileage was 6764 so the 340b had about 1134 miles on it. The cam looked fine. No ugly stuff goin on. It seems to be handling the heavy springs just fine. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 03/20/20 at 03:10:09 The rocker arms also looked fine, and the rocker shafts were oiling good. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 03/20/20 at 03:11:02 The RD valve springs load tested right on the spec (70 lbs on the seat and 190 lbs at .450” lift). They are holding up well. But the stock spring retainers looked unusual. After looking closer I noticed groupings of small pits or craters, possibly cracks or fretting of some sort. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 03/20/20 at 03:12:13 I reached out on the forum to see if anyone else had seen retainers like this. No one had seen it. I assumed that the stock retainers can’t handle the high-pressure springs and figured I would have to put it back together with the stock valve springs. That would require a cam with less lift, so I decided to reassemble with the stock DR650 cam. I needed another set of retainers, so I pulled down my original stock head with the intent of cannibalizing the retainers off that. It only has several thousand miles on it. Low and behold those retainers exhibited the same fretting/pitting/cracking (whatever it might be). I ordered another set of retainers, but they were on super backorder. And to be honest, I really didn’t want to run the stock retainers, they looked sketchy for this application. Now what? I tried a set of valves for a 1995 DR650. The DR650 valves are identical to the stock LS650 valves except the cotter groove is situated lower on the stem. The RD titanium retainers fit just right on the DR valves. Now I could put it back together with the 340b cam. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 03/20/20 at 03:12:59 The DR valves with RD spring retainers required quite a bit of shimming to reestablish correct spring height. As a result, the spring retainers interfered with guide seal installation, so the spring seats had to be trimmed. There must be a gap between the spring seat and the guide seal. Valve travel with the RD retainers and cotters was fine. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 03/20/20 at 03:13:54 This shows a spring seat after trimming next to a stock spring seat. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 03/20/20 at 03:14:37 5/16” x 1-1/4 fender washers make perfect shims. Just drill out the washer to fit over the guide. The big chamfer is for the circlip on the guide. Two shims ( |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 03/20/20 at 03:15:19 Everything looks in order. The valve tips are no longer situated below the top edge of the cotters. |
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Title: Re: Big Cam - Web 340b Install Post by DragBikeMike on 03/20/20 at 03:17:12 I reassembled the engine with a stock cylinder and Wiseco piston instead of the tight quench setup (short cylinder with flat-top piston). Cam timing is at the factory marks (no longer retarded 5°). The engine is back in business and running pretty good. I’m working on a post that compares performance between the tight quench setup and the Wiseco pop-top. It’s interesting. Sure wish I knew what’s up with the stock spring retainers. |
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