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SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> What's the Flywheel for? /cgi-bin/YaBB.pl?num=1529391534 Message started by DragBikeMike on 06/18/18 at 23:58:54 |
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Title: What's the Flywheel for? Post by DragBikeMike on 06/18/18 at 23:58:54 I have seen that a number of members have installed a lighter flywheel. I was thinking that it might be possible to completely remove the flywheel. It's a huge rotating mass. What doe it do? Why is it there? It weighs over 6 lbs. Getting rid of that huge rotating chunk of steel should: -Improve throttle response -Permit the engine to accelerate faster. -Reduce gyroscopic action and allow the bike to be pitched around easier. -Improve compression braking -Reduce the overall weight of the bike. Getting rid of that huge rotating chunk of steel could also: -Make the bike impossible to start (flywheel inertia overcomes compression). -Make the bike difficult to ride (hard to get rolling in 1st.) -Make it hard to maintain a steady speed. -Make the bike rough at cruise (jerking back & forth). -Possibly cause a vibration issue. That big 6+ pound flywheel stores a lot of energy. The old "a body in motion tends to stay in motion" theory. Removing it entirely might upset the apple cart. From what I could gather, most of the folks using lighter flywheels are lobbing off about 2 lbs. Hey, if a little bit is good, lots must be better. I wanted to see what would happen if I turned the flywheel into a spacer. So read on and see what I found out. |
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Title: Re: What's the Flywheel for? Post by DragBikeMike on 06/19/18 at 00:16:37 I disassembled the left side of the engine. You can use a 36mm open end wrench to hang onto the alternator rotor while you impact off the bolt. I found out that 36mm offset wrenches are pretty hard to come by but 36 mm combo wrenches are a dime a dozen. To hold the flywheel while I removed the 46mm nut I fabricated a simple tool using 3/16" bar stock and a couple of spacers. You could even stack up a bunch of washers instead of using spacers. It's important that the connection be rigid. I had purchased a 46mm socket but I would have had to chop it in half and convert it to a deep socket. Also, it was a 12 point socket and you really need to use a 6 point since the nut is so thin. I surveyed my old tool bin and found my old Harley pulley nut socket. It's 1-7/8" and plenty deep, so instead of struggling with a big socket chop-up and weld job, I epoxied six .030" steel shims into the socket to do a quick conversion from 1-7/8" to 1-13/16" (46mm). Worked like a champ. Here is a pic of the simple tool & modified socket. |
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Title: Re: What's the Flywheel for? Post by DragBikeMike on 06/19/18 at 00:20:13 Here is another pic of how the holding tool is installed. The bosses on the frame for the footpeg work perfectly to restrain the tool and prevent the flywheel from turning. It's super easy to fabricate the tool. |
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Title: Re: What's the Flywheel for? Post by DragBikeMike on 06/19/18 at 00:27:59 The flywheel weighs 6 lbs. 0.2 ozs. It is a little over 6-1/2" in diameter. Initially I thought I could simply replace it with a spacer, but after closer examination of the assembly it became apparent that this beast forms an integral component of the starter drive. I didn't want to create a problem with the flywheel nut continually backing off so I opted to "chance-um" and machine down the original flywheel, thus retaining the splines and preventing any undesirable rotation during starting. Don't want that big nut comin loose. Here's a pic of the original flywheel and starter gear. |
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Title: Re: What's the Flywheel for? Post by DragBikeMike on 06/19/18 at 00:39:50 I made a spud to mount the flywheel in my lathe. Since this is part of the rotating assembly, you want to maintain concentricity and perpendicularity as you machine away the unwanted material (at least I hope it's unwanted). Optimum runout would be .001" TIR or less but I used a threshold of .002" TIR. That seemed reasonable since I was removing almost the entire flywheel. If you plan on only removing an inch or so, then stick with a max OF .001" TIR. You don't want a shaker. Setting it up in a 4 jaw allowed me to zero it right in. Here's a pic of the spud. |
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Title: Re: What's the Flywheel for? Post by DragBikeMike on 06/19/18 at 00:51:17 Man, hacking off 3-1/2" of solid steel is a BIG job on a tiny Chinese lathe. But it can be done. I had a problem maintaining surface finish. At first, things went really nice, but as the diameter reduced, the cut became hard, sparks flew, tool bits disintegrated. I'm thinkin maybe my tool bit height was higher than it should have been. Any machinists out there got any ideas. As the diameter reduced it got harder and harder to maintain a decent cut. I tried increasing the rpm to maintain surface speed but it only made things worse. Here is a pic of 5 lbs of machining chips. Lots & lots of work. Hey! I'm retired. |
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Title: Re: What's the Flywheel for? Post by DragBikeMike on 06/19/18 at 00:56:01 I took the flywheel down to exactly 3.000" diameter. As I mentioned, surface finish was a problem but I wasn't worried about a fracture resulting from some sort of defect. The diameter was reduced to a point where that would no longer be a factor. There was essentially no more rotating mass. It was simply a spacer at this point. Here is a pic of the finished flywheel (spacer). |
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Title: Re: What's the Flywheel for? Post by DragBikeMike on 06/19/18 at 00:59:45 In order to reinstall the beast, I would need some way to hang on to things while I tightened the flywheel nut. I fabbed out a clamp assembly to use in conjunction with my cheapskate flywheel holder. It worked perfect. I tightened the nut to 110 ft-lbs. with no slippage. Here is a pic of that tool. |
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Title: Re: What's the Flywheel for? Post by DragBikeMike on 06/19/18 at 01:01:42 Here is a pic of the installed 3" flywheel (ummm! spacer). It's obviously a BIG change. Hope this wasn't a mistake. |
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Title: Re: What's the Flywheel for? Post by DragBikeMike on 06/19/18 at 01:23:28 Well, how did it work? It started right up. No issues with flywheel inertia. It idled exactly the same. It had pretty much the same throttle response. Shoots, I was expecting big league WhaaaapAhhh and got the same old vroom vroom. It drove off a stand still pretty much the same, maybe needed a bit more clutch-work to get it rolling. Felt pretty much the same on surface street roll-ons. What's up? Six pounds less rotating mass and essentially no change? On the freeway, 55 to 75 feels much smoother and quicker. Here's the kicker, "smoother". The WOT acceleration at speed is "smoother" & appears quicker. I would have thought the flywheel would have kept the acceleration smooth, but it feels smoother now, and feels quicker. The whole deal defies logic. I was expecting enhanced throttle response in neutral, but it feels same. I was expecting jerky operation but it feels smoother. I was expecting driveability issues but its pretty much the same as before. How do you lose 5 lbs of rotating mass and have almost no change in driveability? I ain't much of a road racer so I can't comment on how it flicks around, but let's face it, if you nullify the 6 pound gyroscope spinning around right at axle level things gotta flick better. Compression braking feels about the same but I'm not in to breaking the rear skin loose with a downshift. Bottom line, the mod works OK. No need to worry about screwing things up. It starts and drives pretty much the same, and acceleration appears to be better and smoother. You will lose about 5 lbs of curb weight. It should flick better due to reduced gyroscopic action. It's all good. So, why did the OEM put this thing on the LS650? |
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Title: Re: What's the Flywheel for? Post by justin_o_guy2 on 06/19/18 at 02:22:10 That's not the report I expected. Is it worth doing? Do you see a net gain? |
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Title: Re: What's the Flywheel for? Post by Armen on 06/19/18 at 02:50:00 I have been cutting the flywheels down for Dave to sell, but not that much. I stop where the threads are so that the flywheel can be removed and installed easily. Interesting that cutting it down as far as you did didn't change the manners much. Heavy flywheels hide a lot of problems, and generally make drivability a bit more relaxed. On Ducatis, I knock a few pounds off the flywheel and the bike revs faster, turns easier, and feels faster. There is an aftermarket aluminum Duc flywheel that weighs ounces. More than a few folks installed them, then went back to steel as the low end running became too jerky. Others love them. BMW from the late 60's to the early 80's went thru a few incarnations of flywheels, eventually ending up with one so light they stopped calling it a flywheel, and just call it a clutch carrier. You can feel a significant improvement in ability to rev, and a definite increase in vibration as the flywheels got lighter. I think the last incarnation are too light. My '91 buzzes so bad at speed the mirrors are useless. So, that's why I settled on knocking a few pounds off the Savage flywheel, but not all of it. Thanks for the pics and the report! |
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Title: Re: What's the Flywheel for? Post by Dave on 06/19/18 at 03:54:21 01070874767175450 wrote:
We affectionately refer to this item as "flickability" on this forum......and the result is a small grin whenever we get the chance to use our new word. I have one of Armen's "small" flywheels on my bike right now. I had a medium sized one from the first batch on last year. The medium size one resulted in about a 1/2 second reduction in the 0-60 mph time - I really could not tell any difference in the feel of the bike. Why did Suzuki use this large flywheel? My guess would be that they wanted the bike easy to ride and tough to stall when letting out the clutch.....it provides an aid to the new rider. When you look at the rotating mass of the crankshaft, electrical rotor.......and the counterbalance shaft that spins twice the engine rpm - there is a lot of rotating inertia and does make you wonder why they also put a large flywheel on the bike. If you look at the color of the flywheel, it appears they induction hardened the spline area. As you machined the flywheel and got close to the center, I suspect you started to reach the metal that was hardened. |
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Title: Re: What's the Flywheel for? Post by bobert_FSO on 06/19/18 at 05:45:32 Interesting results. Not what I would expect based on previous experience (not with a Savage). When I was a kid, I knew a guy that was into motocross. He had a 175cc 2-stroke bike with some pretty wild cylinder porting and the flywheel removed. It was almost un-rideable. Hard to get moving without stalling. instant throttle response (up and down) made it feel like the throttle had only two positions-- on and off. When it hit the power band, the bike just leaped forward and you would hope you could hang on and keep the front wheel down. Maybe the added heft of the Savage vs a small motocross mitigates some of the harshness of not having a flywheel. |
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Title: Re: What's the Flywheel for? Post by Dave on 06/19/18 at 05:50:04 6E636E697E780C0 wrote:
The difference likely is more related to rotating mass/inertia. The motocross bike had a small crankshaft spinning - and the electrical rotor was also small and light as it only needed to make enough power for the ignition. The Savage has a very large/heavy crank, electrical rotor and counterbalance shaft......I am guessing the combined weight of all those items is close to 20 pounds! Who on this forum is brave enough to relive the days of the BSA Goldstar.....and remove the counterbalancer shaft? (Stock up on threadlocker). ;) |
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Title: Re: What's the Flywheel for? Post by oldNslow on 06/19/18 at 05:50:10 Bit of a hijack but maybe interesting to you guys. The engine in the Indian FTR 750 flat track bike that has been absolutely dominating the twins class in Pro flat track racing for the past two seasons, was designed with an easily changeable flywheel on the left end of the crank. The flywheels are available in different weights, and can be swapped in just a few minutes right in the paddock to accommodate varying track conditions. Flat tract racing is all about finding traction; getting the bike to hook up coming out of the turns rather than just uselessly spinning the rear tire. Heavier flywheels help on slippery tracks. Lighter ons let the engine spin up a little quicker when traction is good. |
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Title: Re: What's the Flywheel for? Post by Dave on 06/19/18 at 06:29:44 The Suzuki GR650 Tempter (1983-84) had a two stage flywheel: From Wikepedia: The bike featured a two-stage flywheel which used a centrifugal clutch to disengage a secondary flywheel above 3,000 rpm, effectively lowering the mass of the flywheel. This was intended to dampen vibration and provide easier take-off at low RPM, and improve responsiveness at higher RPM. |
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Title: Re: What's the Flywheel for? Post by verslagen1 on 06/19/18 at 08:55:44 With the reduction of the flywheel to... nothing I would expect sharper power pulses. Keep an eye on the splines of the output shaft and the dampers in the rear wheel. |
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Title: Re: What's the Flywheel for? Post by bobert_FSO on 06/19/18 at 09:26:55 I had a BSA 441 Victor. My hands were always numb and I could never see out of the mirrors. When idling at a stoplight, you could see the forks shaking the entire front wheel. Even so, I miss that bike. |
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Title: Re: What's the Flywheel for? Post by Todd James on 06/19/18 at 11:21:27 That was a great report, DragBikeMike. Thank you for taking the time to document your work so well and for being willing to risk your own bike in the experiment. You certainly didn't get the results I expected. I agree with Dave that the crankshaft, electrical rotor, and counterbalance shaft make up for the loss flywheel inertia. |
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Title: Re: What's the Flywheel for? Post by norm92de on 06/19/18 at 16:08:09 Dave, I think you have it figured out. The total rotating mass is reduced but not as much as 'eliminating' the flywheel would imply. There is so much mass to the entire crankshaft assembly that while the flywheel is considerable it is not as large a portion as logic would indicate. |
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Title: Re: What's the Flywheel for? Post by DragBikeMike on 06/19/18 at 19:46:20 I had a chance to take a nice long ride on it this morning (about 30 miles). I am pleased to report that it really runs nice. There is no question about improved zip. Dave's comment on cutting 0-60 time is probably spot on. I assume he used some sort of GPS to measure that. I would not use 0-60 because the launch becomes a factor. I would use say 45-65 on the freeway. That way you could stay within legal minimums and maximums and also eliminate the launch which is very hard to do exactly the same from run to run. Hey Dave, what are you using to capture the 0-60 time? I wish I had some sort of electronic timing device to evaluate these changes. The seat-o-da-pants stuff I provide has too many factors that can make you think it's accelerating faster when it isn't. That's one reason why I prefer very quiet exhaust and induction systems. I don't want all that racket influencing my interpretation of how the bike is running. With the lighter flywheel, I can't tell a lot in the lower gears on surface streets. Probably because it always revved pretty fast in 1st thru 3rd, but when I get it on the freeway it's pretty evident. I did a sweet 50-80 uphill run on the freeway and it hauled freight. Its deceptive because its smoother (for lack of a more descriptive word), but when you start bearing down on the cars up front you realize its accelerating pretty fast. I really need to get it back on the dyno. Regarding JOG's question, yes, its worth the trouble. Is it worth it if you are already running a lightened flywheel? I don't know. But if you have a stock wheel, I wouldn't hold back. Take it all the way down to 3.000". Make some tools to hang on to it and go have some fun. I actually suspect that you could get away with using a rattle wrench to reinstall it rather than make the special clamp, but I'm more comfy with applying the proper torque. Regarding Dave's comment about the induction hardening. I also noted that discoloration when I first removed the wheel. Came to the same conclusion, induction hardening of the splines and the surface that bears on the inner race of the main bearing, but it looks to me like it's pretty much confined to the area around the splines. I use carbide inserts in my bits and those puppys can take a beating. As soon as I felt the increased pressure on the hand feed I backed off to check things out. I ran a mill smooth file across the edge of the workpiece. It was dead soft. I'm pretty sure I had the bit too high. I just haven't got around to checking it yet. I'll let you know what I figure out. With a little care, lot's of cutting oil, and frequent insert changes the finished product came out OK. There's always something to learn. Regarding Verslagen's comment on monitoring output shaft spline and dampers in wheel. Thanks for the tip. It's a good observation. I may not be able to sense the rotational pulses but that big, heavy pully sure does. I already keep a close eye on that output shaft nut. When I was doing the cam timing check I was using the pulley nut to rotate the engine. That nut came loose. Not good, the bike was new with only about 1100 miles on it at the time. I have seen some posts on the forum that discuss the problems with that setup. I personally do not agree with the idea that the nut works loose due to the belt tugging on the pulley during acceleration and deceleration. I have owned a motorcycle of some sort or another from 1968 to the present day. Almost every one had a chain drive. I have never experienced the splines in either the counter sprocket or on the output shaft wearing out. I think the pulley spline problem is related to the size and weight of the pulley. If you ever look at a Harley pulley you will note that the boys & girls at the Motor Company don't mess around with cheesey lock-tab washers. They slather up the threads with Loctite 271 and torque the daylites out it, then they lock it in place by installing a hardened socket head cap screw that bears hard on the appropriate corner of one of the flats on the nut. The first time I laid eyes on that I knew they had an inertia problem. I put 53,000 street miles on that belt drive and never once did the nut even think about coming loose. It was always a huge undertaking to get it off. The pulleys are large diameter and heavy. When they accelerate and decelerate they simply don't want to change direction, add to that the belt tugging on it and you have a recipe for disaster. I think I saw one post in here where a member actually welded his pulley to the output shaft. That's desperate. I learned a bunch from this project. I took a chance and got lucky. It was a lot of fun and the results were good. If it helps any of you with your Savage then I am pleased as punch. The sole reason I purchased my LS650 was to use it as a test bed. I want to see how far I can take it and still have a pleasant and reliable scooter. |
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Title: Re: What's the Flywheel for? Post by Dave on 06/20/18 at 04:22:41 I looked at the parts diagram for the DR650....the "hot sister" of the LS650, and it does not have the extra flywheel. I suspect we really don't need the flywheel for anything but a learning aid to help prevent stalling while we learn how to use a clutch and throttle gracefully. And yes.....my speedometer is a GPS and it has both a 0-60 and 1/4 mile timer. I am not a fan of the launch from a standing start.....I believe that the launch from a standing start is about the most abuse you can impose on the drive train. I tried to be consistent in my starts and get away quickly while not "dropping" the clutch - I have very high gearing and my bike is not set up for drag racing. My 0-60 times dropped from around 5.5 seconds to 5.0 seconds with the mid-size flywheel - I suspect the times could be reduced if I went back to the stock gearing and was more abusive with my launch. |
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Title: Re: What's the Flywheel for? Post by Fast 650 on 06/20/18 at 08:28:53 There are some apps for smartphones that do 1/4 mile runs broken down into 0-60, 330 ft, 660 ft, 1/4 mile, and top speed for that run. The one for Android is called Car Performance. The paid version gives you a countdown timer for the start, and the free version starts as soon as it senses movement. That one could be a good thing since it takes reaction time out of the equation. |
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Title: Re: What's the Flywheel for? Post by justin_o_guy2 on 06/21/18 at 09:24:40 Dampens power pulses Protecting gears , bushings, belt, etc. How much is lost in years/miles? Any, or some? Who knows? |
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Title: Re: What's the Flywheel for? Post by batman on 06/21/18 at 19:50:19 I'm going to get rid of half my clutch plates to lesson rotating mass ::) |
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Title: Re: What's the Flywheel for? Post by Armen on 06/21/18 at 19:54:55 Batman, I went to an aluminum clutch basket and plates on my Duc. Def a serious weight/rotating mass reduction. Clutch spins slower than the crank, so the flywheel effect is lessened. |
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Title: Re: What's the Flywheel for? Post by DragBikeMike on 06/23/18 at 13:38:15 Just an update on my tool height. I was about .017" too high so my bit was rubbing rather than cutting. Found a couple of good YouTube videos. Both show really easy ways to check for proper tool height, and I could have done it with the workpiece in place. https://www.youtube.com/watch?v=AyOVFzCuGSs https://www.youtube.com/watch?v=vpCu56O8AJ0 |
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Title: Re: What's the Flywheel for? Post by srinath on 06/09/20 at 09:55:31 1B202D3A2B273C3A2129243B480 wrote:
I own 3-4 of these things, I actually have 1 in the original frame that I did ride and took apart to fix a base gasket leak, and have 2 of the motors in GS500 frames. There are 2 popular mods on this - and both report "great" results. 1 - flywheel is disengaged all the time. So 3-4K disengaged - nope, its always so. 2 - Permanently coupled. What I have realized is, that disengaging makes for a disconcerting feel. I'd rather it was one way - or the other. LOL. BTW the XS650 - the 10+ year earlier predecessor to the GR650 had none of this BS and was a perfectly fine bike LOL. Cool. Srinath. |
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Title: Re: What's the Flywheel for? Post by Zepp on 06/10/20 at 11:16:01 I dont know.. but as a formar race mecanics, it was my brother that did the driving/racing! Everybody had almoste shift to a lighter flyeweel.. so he altso by one, very expensive! It suposed to get at least a better gas respons.. it didnt, and there are resons for that! And the reason for that is, it get faster respons whit no gear in.. whit the gear in and driving one moste count the whole e´weight of the car.. or bike! The only good outcome is that is easyer to shift gear!!!! And thats what its about, easy gear shifting!!! And the drawbacks, it did perform bad at low revs, like driving it frome the depoe to starting line.. after that.. race cars supose to goe att highest revs as posibly. Soo its about the inertia.. this bike is a thumper, I can always put it on the stand and it puffs around anyway. To that.. I think that enginers on Suzuki have figur it out anyway? But if one dont ride on low to middel revs, one dont need that much of a flyweel.. one got the inertia by higher revs. And to that, nr 2, its seems to me that the balance axcel system are heavyer then the flyweel? One dont need that eighter on high revs, but then, one can only drive att hig revs? Summarised, less inertia make one shift gear a lot faster/easyer, thats important on race tracks! One dont got a better accelration on the bike/car.. becuse then the inertia one have to move is the whole bike/car! This bike is a low weight bike, thats good, less inertia to move around, its a thumper, gonna need some inertia in the engin to run smotly. Sooo I have another kind of cheep proposal.. the inertia of the bike and driver is the major problem, the bike is very low weigt, nothing more to do there.. then its more about the driver, losing some pounds or kilos, gonna do more then geting a low weight flyweel? :) |
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Title: Re: What's the Flywheel for? Post by Dave on 06/18/20 at 17:54:29 Next time I have a Savage apart, I will weight the rotating parts. There is a huge amount of mass in the crankshaft, the electrical rotor and the balancer. The flywheel on the Savage does add some momentum - but for the majority of us it has proven not to be necessary......and the bike accelerates a bit quicker with less flywheel mass. |
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Title: Re: What's the Flywheel for? Post by DragBikeMike on 04/09/21 at 13:16:23 I stumbled across this interesting YouTube vid and thought it would add a little perspective to this old post. The Russian adds a whole bunch more flywheel to his little car. It behaves as you would expect. His observation regarding clutch engagement and how the additional flywheel would be beneficial to a student driver seems germane since the Savage is billed as a beginner bike. Crazy project. I love his stone-axe approach. Just go for it. Great that he increased the mass in steps by adding additional flywheels one at a time. Wish he had some snow-free roads to do the test. https://www.youtube.com/watch?v=0M92bfoJZMo |
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Title: Re: What's the Flywheel for? Post by ohiomoto on 04/09/21 at 17:25:06 We used to swap out aluminum clutch plates for steel plates in mx bikes if we wanted to smooth out the delivery and increase traction. It was more prevalent in the off-road disciplines like enduro and hare scrambles. |
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Title: Re: What's the Flywheel for? Post by Dave on 04/10/21 at 03:52:56 He adds the third flywheel and proclaims - "The bolts are too long no more!" I have watched several of videos from this guy......including the one where he made a wooden crankshaft. He is not afraid of spending a lot of time on creative projects that are likely to have unhappy endings. Back in the early days of gasoline engines - if was not uncommon for opera houses and similar buildings to have their own generating plant. The Cit of Walton where I was City Engineer used to have an engine and dynamo and they made the electricity for the town. These single cylinder engines would be modified over the standard engines by having larger/heavier flywheels - so that the engine rpm would stay more even over the compression/exhaust stroke.....and these engines were throttle governed rather than being the hit/miss type of engine. If the rpm varied the electric voltage would change.....and the lights would get brighter/dimmer as the rpm varied. Big flywheels are great for things like tractors, generators, trains, ships and any use where you want a steady output of power and a constant speed - light flywheels are best when you want to vary your speed rapidly. Road driven cars and motorcycles are a compromise as you do want steady speeds at times - but you also want the ability to accelerate. € |
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Title: Re: What's the Flywheel for? Post by DragBikeMike on 04/10/21 at 13:13:37 I'm curious what effect it has on top speed. Our big single-cylinder engine has a long interval between power strokes. We get 180 degrees of push and then have to wait another 540 degrees before another push occurs. Of that 540 degrees, 180 degrees is used to compress the fresh charge. Seems to me that the stock flywheel might help store some energy that can be used to barge through the wind until the next power stroke occurs. Note that the Russian said the engine didn't want to slow down. Multi-cylinder engines have smaller pushes spaced closer together. Two-stroke singles get a push every 360 degrees. I have a self-imposed prohibition on LSRs. After my WOT fry job on the old tight-quench motor, I decided that top speed attempts would no longer be prudent. But for quite some time now I have pondered that flywheel. I'm confident that the 3-inch flywheel improves my rate of acceleration, but I have this suspicion that the BIG flywheel might be beneficial for a LSR attempt. I plan to do some tests on the acceleration aspect but I'll leave the LSR stuff to the guys who live in Nevada. A phenomenal amount of energy can be stored in a rotating mass. Big heavy flywheels can be dangerous. There's just no stoppin them. Ohio, were those dirt bikes with the aluminum clutch plates Huskys? |
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Title: Re: What's the Flywheel for? Post by ohiomoto on 04/12/21 at 04:34:14 No. All the Japanese 125s and 250s used aluminum plates. There were a few Honda 250s in the late 80s and 90s the hit particularly hard so some guys were using steel plates. I tried it and it made a small but noticeable change. |
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Title: Re: What's the Flywheel for? Post by Hiko on 04/20/21 at 20:20:00 I guess this lightening of flywheels is to get more acceleration Some Dr 650 guys drill bigger breather holes in the bottom of their flat slides and cut a few tiurns off the diaghram spring to lessen the preload to get quicker throttle response Has anyone tried this on our savage? |
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Title: Re: What's the Flywheel for? Post by verslagen1 on 04/20/21 at 22:38:10 it's in here somewhere... http://suzukisavage.com/cgi-bin/YaBB.pl?num=1615569533 |
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Title: Re: What's the Flywheel for? Post by Zepp on 05/06/21 at 16:13:07 Its still this.. the flywheel is only a (1) part for storage of energy frome the combustion, to make the enging going 720 degres.. IE one whole cycle. Its still a thumper, and there are heavyer parts to, like the crankshaft, and the balance axell, and to that even the generator. And its still to make the engin to work even att low/medium revs. There are both pros and cons of this.. perticulary this this engin only have one cylinder. Pros is that ir uns even at low and middle revs.. its usable for moste people. Cons is, there is a lot of inertia to make it turn 720 degres to get a new combustion. That makes the engin not that fast to react on the gas handel, whit the clutch not engaged.. there is a delay for shifting gear. Thats not a problem.. one get used to ones bike and how to shift gear. To that, whit clutch engaged and any gear in postion, then it shifts to the inertia of the whole bike + the rider. Soo, one can get rid of the flywheel, the balance axcel and the generator, only use highest ever tollerable revs.. then its become a dragbike, its stupid.. but one can probably get some better accelration out of it.. if its used as a drag bike. |
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Title: Re: What's the Flywheel for? Post by Dave on 05/07/21 at 02:31:23 1B243131410 wrote:
Zepp: As you stated in your post, there is a lot of rotating mass in the Savage. The crankshaft is heavy, the balance shaft is heavy and spins at twice the engine speed, and the electrical rotor is heavy......as is the flywheel. I installed a mid-weight flywheel initially, and then later I installed a super light flywheel - and I really have not noticed any "cons" to the switch. The "pros" are that I did cut my 0-60 time by 1/2 second with the mid weight flywheel as measured by my GPS speedometer.....I have not done a timed run with the super light one yet. The bike idles the same, starts just as easy, cruises the same - it appears that all the other spinning parts have plenty of rotating mass to keep the engine happy. Speculation doesn't always prove to be accurate - thankfully DragBikeMike documented his experience.....and Armen made us some light pulleys for those of us who cannot build our own. The folks who have installed them all believe they work great! :) |
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Title: Re: What's the Flywheel for? Post by DragBikeMike on 05/07/21 at 11:22:11 My current project involves a bunch of incremental tests starting from a box-stock engine. The flywheel mod will be included. Hopefully I can add some useful data on the flywheel. I'm very curious how the timed runs will stack up with my old seat-o-da-pants evaluation. One thing that has baffled me from the git go is the "rap in neutral". It simply doesn't seem to rap any faster with the small flywheel. I've reduced rotating mass on a number of different engines. They always rapped faster in neutral, behaved exactly like the Russian's Lada. The Savage did not respond like that. Nothing beats collecting hard data. |
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Title: Re: What's the Flywheel for? Post by Armen on 05/07/21 at 12:31:05 Rap? Rev? |
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Title: Re: What's the Flywheel for? Post by Zepp on 05/07/21 at 16:39:00 1D262B3C2D213A3C272F223D4E0 wrote:
Zepp: As you stated in your post, there is a lot of rotating mass in the Savage. The crankshaft is heavy, the balance shaft is heavy and spins at twice the engine speed, and the electrical rotor is heavy......as is the flywheel. I installed a mid-weight flywheel initially, and then later I installed a super light flywheel - and I really have not noticed any "cons" to the switch. The "pros" are that I did cut my 0-60 time by 1/2 second with the mid weight flywheel as measured by my GPS speedometer.....I have not done a timed run with the super light one yet. The bike idles the same, starts just as easy, cruises the same - it appears that all the other spinning parts have plenty of rotating mass to keep the engine happy. Speculation doesn't always prove to be accurate - thankfully DragBikeMike documented his experience.....and Armen made us some light pulleys for those of us who cannot build our own. The folks who have installed them all believe they work great! :) [/quote] Thanks, I dont disagre that much frome your opinion! There is a lot of spining mass in our engin. And mayby some Suzuki enginers put on a to heavy flywheel, to make it work for non experiancde drivers? In anyway.. it still dont affect the inertia of the bike+driver that much. Whats afect the inertia of a wehicel is weigt of both wehicel and driver. And there is more to that.. one other importante thing how much clutch engagement time. To that.. the engin need clutch to be to deliver power for forward drive/acceleration.. its basic mecanical/fysic understanding. Then to next understanding.. to shift gear.. preferably the input and the outpout shaft should have similar turning rates.. its becuse of that we use the gas handel to eighter lower or rise the engin speed! Any experianced rider dont ever think of this.. the juste do it.. by experiance! And then to acceleration.. its about full clutch engagement on full gas handel! Its easy to this on first gear.. then come some minor problems.. one need to shift to another gear.. and later to another.. it take seconds with no clutch engaged and gas handel lower to engage any next gear! Summarise.. inertia/weight of moving parts of our engin dont do affect that much acelleration except clutch engage/full gas time. In another solution, get rid of any helmets and other heavy biking clothings and one can probably get som better speed records.. dont do this at home.. its only stupid and dangerus! I think I alredy sumarised.. but in case, dont drive naked on a bike, and dont even think about that a lighter flyweel gonna afect accelration on any bike.. except clutch time on a racing track. :) |
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Title: Re: What's the Flywheel for? Post by Dave on 05/07/21 at 17:53:42 59667373030 wrote:
On my bike going from the stock flywheel to the mid-weight flywheel reduced my 0-60 times by 1/2 second. My GPS speedometer has a 0-60 timer and I made several runs with the stock flywheel and my times didn't vary much. I don't really do a drag race start and rev the engine and drop the clutch - but I did try to leave the line quickly and consistently. I went home and leaned the bike over on the right side and changed the flywheel as quickly as I could.....with my Cafe' bike I can remove the left side cover without having to remove the foot pegs. I then went out and made more timed runs with the mid weight flywheel. My times with the lighter flywheel were consistently 1/2 second quicker. I could not tell any difference in the smoothness of the idle or any change in vibration while riding....and the seat of the pants really could not feel the change in acceleration - but the timed runs showed there was a change in the rate of acceleration. DragBikeMike tests in a different manner - he times his acceleration in 3rd gear between 4,000 and 7,000 rpm. The way he tests eliminates the variance in getting a good start or shifting gears. Hopefully his upcoming tests will show what (if any) changes in acceleration he has with the light flywheel. |
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