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Yamaha XS650 Experimental Clutch

Discussion in 'The Garage' started by TwoManyXS1Bs, Oct 18, 2016.

  1. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Continuing the saga of the Clutch Experiments.

    This summer, I upgraded my XS1B from its original early style 70-73 6-plate clutch to a later model 74-79 7-plate clutch. The upgrade includes an experiment to address the "sticking clutch" issue, and to see if it helps with the "finding neutral" problem common to many XS650s.

    A Google or Youtube search on "Stuck clutch" finds numerous videos and articles on this, and it occurs on many other bikes. So, we're not alone in this issue.

    This particular experiment takes advantage of features which I believe are unique to the XS650 clutch, so I don't expect it to help other bikes.

    This thread by member Tyler Jay has a video that shows the typical stuck clutch problem:


    This video shows the Experimental Clutch action:

    johnnyc14 likes this.
  2. weekendrider

    weekendrider Iron Horse cowboy Top Contributor

    S.W. MO

    Still :umm:
    Last edited: Oct 18, 2016
    roadstar06 likes this.
  3. xjwmx

    xjwmx XS650 Guru Top Contributor

    How are you causing the plates to separate like I'm seeing? I have had the problem you describe but it goes away if I adjust the cable so the clutch disengages sooner, therefore has more separation when the lever completely pulled. But I think your clutch might have interesting characteristics and be fun to use.
  4. JesseeS

    JesseeS XS650 Addict

    What is this witchcraft. Very cool!
  5. 5twins

    5twins XS650 Guru Top Contributor

    Yes, you must tell us what you've done, and more importantly, whether we can do it too, lol.
  6. gggGary

    gggGary Stop that! XS650.com Supporter Top Contributor

    It's all smoke and mirrors I tell you!
  7. MaxPete

    MaxPete Lucille, Betty & Demi - I suggest but THEY decide. XS650.com Supporter Top Contributor

    Indeed - I don't understand what the term "experimental" refers to. Is it just that you have switched to a later model clutch assembly on an early bike?

    Please fill us in - enquiring mind want to know!

  8. xjwmx

    xjwmx XS650 Guru Top Contributor

    Pretty sure Dogbunny is off-camera sticking his afro pick in there.
  9. gggGary

    gggGary Stop that! XS650.com Supporter Top Contributor

    Only two ways I can come up with are springs metal or rubber. or some sort of a spiral so reverse torque spreads, forward torque clamps, that would be cool but complex. Yamaha used a spring a couple of years. Supposedly as a clutch stick reducer, and to smooth engagement. There's a how to, to remove them. The Late model Yamaha Ventures have an o-ring and half plate, Those are the first things to get pitched when the clutch starts slipping at fairly low miles (normal on that bike).
  10. Signal

    Signal XS650 Junkie Top Contributor

    2M you are always up to something. Watching with interest, thanks for posting.
  11. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Well, guys, I have mixed feelings about revealing the inner workings of this contraption. The concept is simple, but is very involved and complicated, and requires darn near watchmaker precision to implement. It's definitely not ready for "Prime Time".

    I have over 50 pics of the build details, still not enuff to cover it all. The writeup would likely be ardously long, like the 'instrument rebuild' thread. It's really just an experiment, and 'proof of concept'. As it is right now, its not a marketable product. I wouldn't recommend implementing it. Like what happened with the clutch worms, there could be a run on XS650 clutches, and the supply of spare clutches may dry-up before 5Twins can stock up. :yikes:

    It doesn't use any form of springs or o-rings, I didn't want anything competing with the clutch springs. Those early model 'plate spreader' o-rings were definitely a bad idea.

    A quick patent search shows that this probably is still an active area of research.


    This particular version is completely different from those methods. But, it's done 'my way', which is definitely not suitable for production, and worse, difficult to explain.

    For now, I'm using it for insight.
    Does it help with the 'stuck clutch' issue?
    Does it help with the 'finding neutral while stopped' issue?

    It's still too early to endorse the perceived benefits of this thing. But, so far I can tell you that I haven't experienced the dreaded 1st gear *clunk*-*lurch*-*stop*. The shifting area is a different story.

    I've got some other experimental tweaks going on simultaneously with the shifting/starwheel stuff. In theory, you would think that eliminating clutch drag from the shifting chores would improve the shifting character. But, I'm getting some interestingly mixed results. Sometimes the shifting is markedly improved, smooth 'snicks' thru the gears like on some of the better Honda transmissions. Other times it almost doesn't want to shift at all in the 1st-N-2nd region. In all cases, finding neutral while stopped is much worse.

    Change variables, observe results, the nature of the experiment. Right now, it would seem that the clutch may not be the responsible party to the shifting issues, and I have my suspicions. After all, many other bikes shift fine without this 'plate spreader' mod. At least it doesn't seem to get 'stuck', but time will tell.

    The experiments continue...
    Last edited: Oct 18, 2016
  12. weekendrider

    weekendrider Iron Horse cowboy Top Contributor

    S.W. MO
    Well HELL. It's the pits when you are sure something will help a situation, but turns out making it worse.
    Enjoyed the video and missing nowhere to be found pressure plate trick :wink2:.
    Can you confirm or deny, was DogBunny's fro pick involved? :laugh:
  13. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Haha, WER.
    No DogBunny afro picks were harmed in the filming of this video.
    I wish it *was* smoke and mirrors. Much easier to do.

    Warping time and space is *much* harder.
    The DOD keeps following you around...
  14. xjwmx

    xjwmx XS650 Guru Top Contributor

    Patents are a total minefield. I'm co-inventor on a few that my company got. co- because of hanger-ons. I was the guy. Anyway there are so many insane ways to circumvent patents that you need the best patent attorney in the U.S.A. or it's useless. You'll also encounter roving bands of patent attorneys who buy up patents and then sue people they claim to be infringing. The only way to stop them is imply the Fredricksburg mafia will literally kill them without coming out and saying it.

    Interesting factoid, I invented the remote car starter. In the 80s I was tired of getting into my car in winter and thinking f*** f*** f*** all the way to work where the car warmed up and I got out to go inside at about the same time. So why not leave your car heater set on, and turn your car on just before you jump into the shower? I was heavily into electronics at the time but for the sake of expediency I took the transmitter and receiver from an $11 remote control car, The receiver supplied battery voltage across two terminals when it was active. I used that to trip a relay that hot wired my car. Nobody was interested.

    My last foray into intellectual property was back in the Digital Millennium Copyright Act days. I created a very desirable computer program with the actual intent that it would be pirated. The DMCA provided that users of pirated programs would be fined $10,000 damages. My program would "phone home" and deliver the IP address of the user. Of course he would be using a pirated copy of the program and a court order would reveal his identity and my patent attorney would sue his ass off. I didn't have the heart to go through with it. I learned to program on a pirated copy of Microsoft C, and I know everybody at MSFT in those days, including Bill Gates himself, learned on pirated software as well. I didn't have the heart to go through with it, and colleagues absolutely despised me for even thinking of it...
  15. Uhlaf

    Uhlaf XS650 Addict

    2many this look great, you are a pioneer and expert tinkerer if I do say so myself. Even if it is a little complicated to explain maybe next time you take the clutch cover off you can have your camera rolling and narrate? I'm hoping to tear down my engine this winter and if your bugs and what not are ironed out I'm sure I would be one of thousand that would love to implement this mod, of course all of us know that the clutch is a weak point in our beloved XS's.

    Another thing, does the clutch drag like this on period hondas or kawasakis? What about old triumphs? What makes our clutches operate this way?
  16. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Hey, Uhlaf. Today's the last of our +90°F days before the cold front hits, so will be out riding. Trying to figure out more about the shifting thing.

    Clutch drag, from unnoticable/mild to wild/stuck, exists on just about all of those period bikes with multiplate wet clutches. Nature of the beast.

    Numerous fixes were used, new clutches, resurfaced plates, modern non-cork plates, different oils, additive awareness, oiling mods, ...etc.

    This thing has been cooking in the back of my head for a long time, finally got around to trying it...
  17. weaselbeak

    weaselbeak XS650 Junkie

    I wonder if he's integrating opposing magnets into the clutch plates? Just a theory, but I don't see anyone coming up with anything.
  18. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Hey, weaselbeak. Haha, no, no magnets.

    Pooting around today, getting more of the feeling of this.

    One part I really like is the first start of the day. Don't do the "pull in clutch lever and kick until free" routine anymore. Just drop it into 1st, and it just goes 'snick'.

    What I *am* discovering though, is that our gearshift mechanisms are very sensitive to even the slightest amount of torque applied to the mainshaft, especially while the bike is stopped. Just the slightest amount of clutch drag aggravates this.

    Need to look into dog/cog undercutting, shift fork loads, shiftdrum retainer loads. Thinking about cooking up a test scenario. With bike on centerstand, engine off, trans in 1st gear, hang a weight onto rear of rear wheel (to preload the trans and simulate clutch drag), see how much lifting force applied to the gearshift will get it to 'pop' out of 1st gear. Do this for a series of rear wheel weights, and see if the gearshift lever forces are proportional, or asymptotic.

    Don't have a bike lift, have to do this on the floor. (*grunt*)...
  19. gggGary

    gggGary Stop that! XS650.com Supporter Top Contributor

    Hmm they changed the gear shape in what about 76? tranny has to be changed as a set can't recall the reason offhand. Not to dis your efforts but really I don't have any "out of the ordinary" issues shifting, finding neutral on any of my XS650s. Pretty much all multi plate wet clutch setups to this day will drag the pack at a stop. A quick slight release of the clutch lever, pull back in and tap the foot lever for neutral, done. That "tap" the lever may often be missed No matter how finessed, a steady press won't work as well rather a light tap up of the boot gets the lever to move that "just right" amount that stops in the neutral notch. Kawasaki uses a neutral finder that blocks second gear when the bike is at 0 MPH so a solid stab up still stops at neutral. I like heel shifters, not least because I can tap down to find neutral. My BMW K bike with a single plate dry clutch had a very easy to find neutral even after 130K miles
  20. weekendrider

    weekendrider Iron Horse cowboy Top Contributor

    S.W. MO
    Plus one.

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