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  • Issues with clutch....Surprised?

    Hey guys,

    Just thought I'd ask the question, I'm pretty sure the clutch should be knackered by now....I mean my bike is a 1986 GPZ250R..... And I have been kind of rough on her recently.

    But just within the last 2 weeks its been considerable harder to get off the line without the clutch slipping once I release fully on the clutch, whilst fairly heavy on the throttle. Now thats all relative of course....I probably have 15Nm of torque....total, so its not like it has much work to do but its struggling none the less.

    I played with the clutch cable to make sure that it was allowing the clutch to engage fully before I started blaming the clutch, Once the clutch is engaged it works well, engine braking, hard throttle through the power band (please stop laughing....) the only time its an issue is once I have disengaged, and then have to reengage the clutch.

    So the question finally is!

    Have you had similar symptoms?
    What did you do to resolve them?
    What do you suspect the issue to be?
    Is it worth me trying to fix it myself?
    How much is what you think is busted, worth, if needed to be replaced?


    Now I have done some reading and worked out that I could potentially need some clutch friction plates:

    And maybe some clutch springs:


    So am I on the right track?
    Cheers in advance!
    I got a fever.......and the only prescription is more cowbell!

  • #2
    Hmm... My clutch is worn out and the symtoms start from clutch slipping from the top gears WOT... then gradually goes into lower gears.

    Even after a few months first and second still doesn't slip under WOT. (stars slipping from third gear 8k rpm).

    So I don't think the clutch plates are worn out as it a lot more gradual. Beyond that I have no idea... perharps on of the springs is screwed...?

    P.s I'm buying some EBC fricition plates + ebc springs. Then you would need to get a new gasket for the engine cover and change the oil.
    But that is to get my issue fixed.

    Comment


    • #3
      Originally posted by Xuaxace View Post
      Hmm... My clutch is worn out and the symtoms start from clutch slipping from the top gears WOT... then gradually goes into lower gears.

      Even after a few months first and second still doesn't slip under WOT. (stars slipping from third gear 8k rpm).

      So I don't think the clutch plates are worn out as it a lot more gradual. Beyond that I have no idea... perharps on of the springs is screwed...?

      P.s I'm buying some EBC fricition plates + ebc springs. Then you would need to get a new gasket for the engine cover and change the oil.
      But that is to get my issue fixed.
      Seems strange that its slipping in the higher gears, I mean I don't know a whole lot about mechanics but I would've thought the gears with more turning force would slip more when trying to engage them as oppose to the gears with more (sorry i deserve a flame for this terminology...) "turning quantity"

      Actually thinking about it....both situations one side of the clutch is trying to spin faster than the other, with mine its the engine side, yours is the road/rear wheel side.

      Hmmm...so much to learn....

      So you gonna do all the work yourself?
      I got a fever.......and the only prescription is more cowbell!

      Comment


      • #4
        Someone told me it was because of the ''torque''. Higher gear + high rpm, high torque.

        But basically it starts from the top and starts working its way down,

        I want to do it myself... I don´t have some tools required so I will probably have ask someone to give me a hand hopefully . Clutch is one of those things you don´t want to get wrong, but good thing to learn.

        Comment


        • #5
          The torque loading on the clutch is much higher in the higher gears. The lower gears multiply the torque coming from the engine, going to the back wheel which reduces the load on the clutch.

          Imagine trying to take off from a standstill in top gear. The engine will stall because there isn't enough torque coming through the system to overcome the load. Go down to first gear and the bike pulls away easily with little load on the engine/clutch because the gearbox is doing all the work through torque multiplication.

          If your clutch is slipping when trying to get away from a standing start with lots of revs on board then I would first be looking at your technique. Are you really releasing the clutch fully? Lots of people tend to hang on to that last little bit which doesn't allow the clutch to take up fully.
          Secondly, if it is cable actuated I would make sure that the cable is lubed properly and isn't sticking. I have seen plenty of cables that have rusted inside the sheath and become sticky in operation.
          Thirdly, what freeplay do you have at the lever and where have you measured it from? (might be a silly question but you never know.)

          If it is hydraulic that is a whole other can of worms but from your description I would say the problem lies more in adjustment/actuation rather than in the friction material or springs. That would be my first area of checking anyway. It could be something internal that is stopping the plates from engaging properly but I would be checking those other items first as the symptoms just don't fit.
          Last edited by Veefore; 21-09-2009, 05:57 PM.

          Comment


          • #6
            After all that^^^^^^
            I would be measuring spring length against the specs in your manual.

            They can be washered up for those with some clutch rebuilding experience

            Comment


            • #7
              Originally posted by Veefore View Post
              The torque loading on the clutch is much higher in the higher gears. The lower gears multiply the torque coming from the engine, going to the back wheel which reduces the load on the clutch.

              Imagine trying to take off from a standstill in top gear. The engine will stall because there isn't enough torque coming through the system to overcome the load. Go down to first gear and the bike pulls away easily with little load on the engine/clutch because the gearbox is doing all the work through torque multiplication.

              If your clutch is slipping when trying to get away from a standing start with lots of revs on board then I would first be looking at your teqnique. Are you really releasing the clutch fully? Lots of people tend to hang on to that last little bit which doesn't allow the clutch to take up fully.
              Secondly, if it is cable actuated I would make sure that the cable is lubed properly and isn't sticking. I have seen plenty of cables that have rusted inside the sheath and become sticky in operation.

              If it is hydraulic that is a whole other can of worms but from your description I would say the problem lies more in adjustment/actuation rather than in the friction material or springs. That would be my first area of checking anyway. It could be something like a notched clutch basket that is stopping the plates from engaging properly but I would be checking those other items first.
              Yes it is cable actuated. The operation of the clutch makes sense now, thank you for the excellent explanation.

              I had a look on Zpower is this the best thing to get for lubing a cable or, just friggin spray it down the sheath using the nozzle?


              Appreciate the help guys!
              I got a fever.......and the only prescription is more cowbell!

              Comment


              • #8
                Originally posted by Veefore View Post
                Thirdly, what freeplay do you have at the lever and where have you measured it from? (might be a silly question but you never know.)
                I haven't measured anything! Oh no!!!!

                But seriously, what do you mean?

                The lever is pretty sloppy, don't forget the bike is almost older than me....
                I think its acceptable, I mean I'd love it to be tight! What do I need to check?
                I got a fever.......and the only prescription is more cowbell!

                Comment


                • #9
                  Bump!

                  Can someone help with an answer please?
                  I got a fever.......and the only prescription is more cowbell!

                  Comment


                  • #10
                    How about go to a bike shop and get a qualified mechanic to fix it

                    Comment


                    • #11
                      I have a cable luber and don't live too far from Churchlands. I can pop around after work one evening and take a look at it if you like. Just PM me the details.

                      Comment


                      • #12
                        the freeplay is measured at the end of the clutch lever.

                        You should be able to move the lever 5-10mm without the cable being pulled at all.

                        This ensures that when the lever is let go the clutch really is all the way out.

                        Yes those cable lubers are good. You can get proper cable lube i think
                        Wes

                        Comment


                        • #13
                          cheap check - 1 by 1 remove the 5 clutch bolts and insert an extra washer under each . plug washers may fit . if this cures problem then the springs are due . if still slips replace plates .i recently bought clutch springs - only 40 $ or so .

                          Comment


                          • #14
                            Thanks for the advice guys, did all the basic stuff and it does seem better but its clearly an issue with the clutch internals now.

                            Still goes just fine under light throttle but any hard acceleration and it slips a bit.

                            Oh well. At least it still goes. Have to bite the bullet now I spose.
                            I got a fever.......and the only prescription is more cowbell!

                            Comment

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