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Why are our clutches so troublesome, a theory.

Discussion in 'The Garage' started by kevski, Aug 19, 2019.

  1. gggGary

    gggGary Stop that! Top Contributor XS650.com Supporter

    I just changed handlebars on period piece as I convert it more to my liking, the special length cable now has a "tighter" loop cuz I haven't removed the gas tank to change the routing yet. It noticeably cut the amount of clutch movement as the cable now has to shorten it's path in the bend before it begins moving the worm lever.
    Machine likes this.
  2. 5twins

    5twins XS650 Guru Top Contributor

    No, the XS400 worm gear really doesn't move the pushrod any more or provide more plate separation than stock, it just operates a bit smoother and more efficiently.
    gggGary and TwoManyXS1Bs like this.
  3. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Yes, having a tilted pressure plate can cause the dragging and mushy engagement. Uneven clutch springs will create that "tilt" more so than a non-square mushroom rod.

    You could try balancing the spring pressures, to get a truer running pressure plate.
    Starts at post #80, but you may find the whole thread interesting.

    Jim, grizld1 and gggGary like this.
  4. kevski

    kevski XS650 Addict

    I went through this twomany and it's a great job you done there, it's nice to see that someone else see's there is a problem with these clutches, i always do things by the numbers first and second, so for those that say it's not adjusted correctly are unfortunately wrong, had Yamaha done a better job with the mushroom to start with like a wider head and better fitting shaft with a spiral like rifling running up it we would not be having these issues,, if others got the same system working perfectly then why not Yamaha, maybe budget constraints at the time, who knows, though i shall not be going down the route you have, i will experiment with a longer mushroom and wider head, i have thought of using a KZ one which will mean machining the shaft to fit and re hardening it, we will see how it goes.
    thankyou for putting up your links , there is some food for thought there.
    gggGary likes this.
  5. kevski

    kevski XS650 Addict

    New springs installed and tested to see if different, all the same, today I put back in the two piece rod and adjusted per the manual, no better adjusted at handlebar when out to no avail, so when back I adjusted the actuator when hot and will see what that gives next time out, if still no joy I will modify the pressure plate to take the KZ mushroom which is twice the face diameter and then do the stem so it fits snugly like a valve in a guide this will give a square push, if it works for Kawasaki it'll work for Yamaha, I do have a nos xs650 mushroom coming and will compare it with the old one first.
    timbeck and beano like this.
  6. XSLeo

    XSLeo XS650 Guru Top Contributor

    Early big twin H-D's used coil springs, with a lever and throw out bearing similar to a cars, Later models use a diaphragm and the ball and ramp. Not sure when the change over was.
    I think the Sportster started with the worm style actuator and coil springs.
    gggGary likes this.
  7. kevski

    kevski XS650 Addict

    Well I am waiting on a motion pro cable and a thrust bearing from heiden tuning, but in the interim I got to work on the exhaust valve to push rod mushroom conversion, the more I worked it the harder the material got, but it will be there if I decide to go down that route 20190823_203447.jpg
    TwoManyXS1Bs and 59Tebo like this.
  8. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Thinking on your project, another old memory surfaced.
    A lot of the old Honda clutches I worked on used steel discs with tiny dimples.

    A lot of other motorcycle clutches use these dimpled discs.

    In my experimental clutch thread, I discuss plate surface designs that are supposed to enhance plate separation by introducing aeration of the surface film, breaking the stiction.

    Post #43.

    Our clutch steel plates are smooth, no dimples, possibly promoting that stiction.

    Then I noticed MikesXS clutch plates, # 39-6507, pic appears to show dimpling.


    Can anybody confirm these MikesXS clutch discs are dimpled?
    Last edited: Aug 23, 2019
    gggGary and Mailman like this.
  9. Mailman

    Mailman Hardly a Guru Top Contributor

    Now that is a really interesting observation! I could see how that dimpling could work!
    peanut, gggGary and TwoManyXS1Bs like this.
  10. 650trader

    650trader XS650 Enthusiast

    Motion Pro cables are good and very heavy. The only problem is that they are " Fits Alls" meaning they have one cable
    only for all 650's that are much longer than any stock cable. If you look at a motion pro cable catalog you will see that they
    have limited cables for any bike and only carry the most popular or what they can get to work on many models.
    peanut likes this.
  11. aldo5468

    aldo5468 Redleg XS650.com Supporter

    I've got to put in a good word for EZ Pull cables from 650 Central. I've had one on my bike for many years with never a problem with hard pull or difficulty finding neutral. It is routed in gentle curves; I lube it and the worm occasionally. Three different lengths are advertised, each with the types of handlebars that they best fit.
    peanut, gggGary and Jim like this.
  12. Ratranger

    Ratranger XS650 Junkie Top Contributor

    Motionpro will also make a custom cable in any length and configuration you want for not that much more. So if you have huge apes, or super low clip ons, they can still take care of you. It makes sense not to stock parts that could take years to sell, you get taxed on all inventory.
    peanut, gggGary and Jim like this.
  13. grizld1

    grizld1 Grumpy old man Top Contributor

    Or order cable, cable ends, conduit, ferrules and 50/50 bat solder from www.flandersco.com and make your own.
    gggGary likes this.
  14. kevski

    kevski XS650 Addict

    I have seen this type of plate on different machines and smooth plates, and both not had the issues that the XS sometimes has, I have noticed some wear on the OEM thrust bearing, so am getting the type with a lot more rollers in it, the basket components are all good,so with everything replaced with exception of basket there should be no need for the modification, will update when done.
    peanut, gggGary and TwoManyXS1Bs like this.
  15. peanut

    peanut XS650 enthusiast & inveterate tinkerer Top Contributor XS650.com Supporter

    really interesting topic this and 2M has done a lot of experimental work on improving clutch operation.
    I think you are right on track about the difficulty in finding neutral . It has to be to do with the ball bearing and indent interaction. If I ever need to strip my engine again I'll definitely be looking to improve that interface between the ball bearing and neutral inindent, perhaps milling the indent slightly deeper to recover a sharper edge and possibly changing the spring to a stronger one .

    I have never had any other problems with my clutch and I know it is due to the meticulous way I prepared it before fitting.
    I took each plate both steel and driven and I lightly dressed both edges of each tang of each plate to remove the sharp edges . I did the same with the clutch basket fingers so that all areas of contact had slightly reduced friction .

    All these little tweaks, and others, add up to a nice smoothly operating clutch.;)
    gggGary and TwoManyXS1Bs like this.
  16. kevski

    kevski XS650 Addict

    Done some more work today on the clutch pack, cleaning the glue off of the friction plate tangs which took about an hour, i then checked the inner basket for run-out and that was OK, i then checked the pressure plate and there was a 19 thou run out on the contact face, also at some stage in its life i looks like someone had taken a hammer to the pressure plate as there was a witness dent on its edge, so probably when the bike arrived in the UK the clutch was stuck and was hammered to part the plates, the friction plates had fresh file marks between the friction material pads where solids had built up, so i refaced the pressure plate on the lathe then polished the contact face, got it down to about 2 thou, hopefully this will get rid of some of the skew when plates are separating, i should have looked more closely the first time i had the clutch apart to put new plates and springs in, lesson learnt, that's all i can do now until the bearing gets here now.
    Last edited: Aug 24, 2019
    TwoManyXS1Bs likes this.
  17. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Wow, 0.019" is a lot of runout.
    It's also barely enough to see from a cursory inspection.
    Glad you got it down to 0.002".
    That should really make a difference...
    gggGary and Jim like this.
  18. kevski

    kevski XS650 Addict

    A little more on this, the new clutch bearing came today, where the old one has eight rollers this has around forty so no room for tipping, the story is tons of drag and impossible to get into neutral, new friction plates, now using two piece rod, new actuator, new cable came with bike not motion pro, i am still waiting for it, mushroom cleaned polished and relief put in centre of contact face to stop it fighting against itself, metal plates cleaned and edges beveled slightly to stop locking, preasure plate trued up it was a long way out around 20 thou, this now means that when i pull the lever i can physically turn the preasure plate whereas before no chance, the last friction plate before preasure plate goes on has had about a 2mm strip taken off it as it showed when plate was on, this will stop it dragging when plates bed in, so back together started her up while warming i oiled the clutch cable copiously as i could feel some binding, tried it out although when in gear there is a small amount of drag i can push the bike backwards while sitting on it, a massive improvement, i can now blip the throttle and flick it into neutral now, hopefully when all bedded in and motion pro cable on it will get even better, so no need for further trials at the moment.
    Last edited: Aug 27, 2019
    GLJ, TwoManyXS1Bs, gggGary and 2 others like this.
  19. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Good thread, kevski.
    Peeling back another onion layer.
    It's amazing just how many details need to be addressed with our clutches. For some of us, it's beyond simple parts replacement. Entering the world of remachining and remanufacturing...
    gggGary, arcticXS and Jim like this.
  20. Machine

    Machine Race the wind Top Contributor

    After searching threads for clutch “revisions” amongst the model changes I’ve yet to determine if a 81 clutch (I see 6 friction plates) is a good replacement spare to have around for say a 78 ?
    Thx, -RT

    Attached Files:

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