Liamo Posted February 4, 2012 Report Share Posted February 4, 2012 The clutch on my ZZR1200 slips very, very badly when the engine is cold. Cold ambient temperature also makes the problem alot worse. I had the clutch plates replaced last august before heading off to France which seemed to solve the problem for a while, but once I returned to chilly Ireland it reared its ugly head again. My spannering friend who replaced the plates noticed some movement in the clutch basket at the time and said the big bearing in the clutch was worn, and the plates we took out didnt seem to have any excessive wear. I bought a new one with the intention of getting it fixed this weekend, but on wednesday night when leaving work I warmed the bike up, put it in gear, released the clutch and the bike didnt move an inch. This had happened once before (I cant remember if that was before or after we replaced the plates) but after a few seconds the clutch began to release and gradually we got moving. But on this occasion it wouldnt budge. I got the bike down to him in a van and we replaced the bearing on thursday evening. We also put back in the plates that we had taken out last year, as he reckoned the plates we removed were from an EBC kit (probaly installed by a previous owner) and better than what was in it. After bolting it back up he noticed that there was still some movement in the clutch basket, much much less than there had been, but reckoned although not ideal it wasnt an immediate worry. I let the bike warm well up before leaving his workshop (it was late at night and about -3 ambient temp) and there was no slipping on the way home, The feeling at the clutch was much lighter so the job, I thought, was jobbed. But, the next morning it was back, probably worse than ever. The clutch would release fine (although it was a very cold morning) and wasnt sticking like it had before, but it would slip very badly if I used any more than about 20% throttle. The clutch still felt nice and light, much better than before. The slip gradually goes away as the bike heats up, but it can take 10 to 15 minutes or riding before it has gone completely. So, my question to the PB massive: What the fuck is going on? Thank you in advance Link to comment Share on other sites More sharing options...
szrdave Posted February 4, 2012 Report Share Posted February 4, 2012 What kind of state is the clutch basket in? Wear to the sides where the edges of the friction plates sit could hold the plates slightly disengaged, possible releasing when the basket warms up and expands. TBH if the basket, plates and springs are all within spec it points to an adjustment issue. A quick google shows it's a hydraulic clutch, is the fluid fresh and properly bled? Is there any mechanical adjustment? Link to comment Share on other sites More sharing options...
Liamo Posted February 4, 2012 Author Report Share Posted February 4, 2012 What kind of state is the clutch basket in? Wear to the sides where the edges of the friction plates sit could hold the plates slightly disengaged, possible releasing when the basket warms up and expands. TBH if the basket, plates and springs are all within spec it points to an adjustment issue. A quick google shows it's a hydraulic clutch, is the fluid fresh and properly bled? Is there any mechanical adjustment? Thanks Dave, some marks where the plates hit the basket, but no noticable wear. Clutch fluid was replaced when the plates were done and system was bled properly. The only adjustment I know if is at the lever, but no matter what position it is in the problem still occurs. Link to comment Share on other sites More sharing options...
szrdave Posted February 4, 2012 Report Share Posted February 4, 2012 One more thought, what kind of engine oil are you using? Link to comment Share on other sites More sharing options...
BudgetBoy Posted February 4, 2012 Report Share Posted February 4, 2012 One more thought, what kind of engine oil are you using? I was going to suggest that.. Should be using 10W/40 Link to comment Share on other sites More sharing options...
porter_jamie Posted February 4, 2012 Report Share Posted February 4, 2012 It might have what is known as a PTL, or peak torque limiter in the clutch line. Most cars have them to stop impact damage to the gearbox and halfshafts. They are a one way valve, which lets you disengage the clutch, but has a sized orifice on the clutch engage side, to slow the flow of fluid down. (for clarity, engage is when you take your foot off the clutch pedal, disengage is when you put your foot on the clutch pedal) Typically 1.2 mm to 1.6mm, that kind of thing. In very cold weather the smaller ones (PTL's) in particular can cause the clutch pedal to return slowly or even stick down, especially if the pedal box has an over centre spring. This is an industry wide known issue. You have to balance the functionality of the pedal (ie not sticking down) v protection of the driveline. is the clutch fluid a special spec? look on the lid, it might say some weird ass spec instead of dot4. Did the garage that bled it use the correct stuff? Try bleeding it through with fresh and see what happens. Something else that might be happening is, the bleed port in the master cylinder is only open when the pedal, or lever, if fully disengaged. This means that the fluid in the clutch line can actually 'see' the fluid in the reservoir. As soon as you pull the lever, the port is closed because the seals go past the port, and pressure rises in the clutch line and pushes on the slave cylinder, which pushes the clutch plates apart and disengages the clutch. When is it really cold the viscosity of the fluid increases, and the slave cylinder might not fully return all of it's stroke before you pull the lever for a second time. Loads more fluid will then enter the clutch line, and potentially hold the slave cylinder 'off it's stop' thereby holding the clutch partially disengaged. you could easily over stroke it and damage things imcluding seals. It should sort itself out when you let go of the lever, and the bleed port opens again, but if it is very cold, then it might take a long time for it to bleed back through. If you open the bleed nipple which should be on the slave cylinder you will release any excess pressure that shouldn't be there, and allow the slave cylinder to return to it's engaged position. editted to make sense now i am on a proper keyboard. Link to comment Share on other sites More sharing options...
Liamo Posted February 4, 2012 Author Report Share Posted February 4, 2012 I was going to suggest that.. Should be using 10W/40 Yup, 10W40 bike specific semi synth oil. Link to comment Share on other sites More sharing options...
BudgetBoy Posted February 4, 2012 Report Share Posted February 4, 2012 Yup, 10W40 bike specific semi synth oil. Ok your free play at the clutch lever should be 2-3mm. Another thing which might sound stupid.. But when you took out the old clutch,was there the same amount of plates you put back in.Sometimes you may/may not get an extra one. But as Srdave says if the springs,plate & basket are all in spec its an adjustment issue. BTW i think EBC springs are roughly 2 times stronger than OE. Also some makes of oil don't work well on some makes of clutches as well (so i have heard) Link to comment Share on other sites More sharing options...
szrdave Posted February 4, 2012 Report Share Posted February 4, 2012 From an online 'fiche it looks like the slave cylinder on the LH side drives a push-rod which travels through to the clutch on the RH side. Have you had the slave cylinder off to make sure it returns freely when the lever is released, and there's no crap stuck around it? If there are any bearings in the push-rod assembly (spinning clutch, stationary rod) they'd be worth a check, as is ensuring the rod can travel freely without binding on anything. Link to comment Share on other sites More sharing options...
Pat Posted February 4, 2012 Report Share Posted February 4, 2012 From an online 'fiche it looks like the slave cylinder on the LH side drives a push-rod which travels through to the clutch on the RH side. Have you had the slave cylinder off to make sure it returns freely when the lever is released, and there's no crap stuck around it? If there are any bearings in the push-rod assembly (spinning clutch, stationary rod) they'd be worth a check, as is ensuring the rod can travel freely without binding on anything. This. I had a problem on a GPZ900 clutch years ago which turned out to be the failure of the bearing at the basket end that the push rod sits on. The bearing failure meant the rod was spinning & it wore a step midway along the pushrod this would sometimes 'catch' & prevent the clutch engaging. It's easy to check though, just take the slave cylinder off & pull the pushrod out, there may also be wear on the face of the slave piston as the rod spins on it. Link to comment Share on other sites More sharing options...
Liamo Posted February 4, 2012 Author Report Share Posted February 4, 2012 Thanks lads, I was tempted to whip off the slave cylinder tomorrow for a look for anything obvious, will report back on how I get on. Link to comment Share on other sites More sharing options...
ronenige Posted February 4, 2012 Report Share Posted February 4, 2012 Thanks lads, I was tempted to whip off the slave cylinder tomorrow for a look for anything obvious, will report back on how I get on. Make sure you can push it back in , sometimes the return holes in the master cyl get blocked with whats known in the trade as " cack " Link to comment Share on other sites More sharing options...
kwakbiker Posted February 4, 2012 Report Share Posted February 4, 2012 Had similar probs on my old ZX7R which turned out to be slave cylinder related as opposed to actual clutch probs. Somehow it had some crap(or cack as R1nige puts it) and the seal was on its way out. Dropped a 2nd hand one in as tight on funds and away she went, no more slippage. Knowing kawasaki I wouldnt be surprised if its the same system on your 12, happy tweeking Link to comment Share on other sites More sharing options...
lorenzo Posted February 5, 2012 Report Share Posted February 5, 2012 As they're cheap, i'd be looking at replacing the clutch springs too. Link to comment Share on other sites More sharing options...
Ascalon Posted February 7, 2012 Report Share Posted February 7, 2012 hey mate, it's worth actually whipping out the clutch push rod too and seeing if it is sticky. Remove the slave cylinder and look at the tip of the rod protruding through the casing. A needle nose pliers will take it out and see if it is worn or bent. Also, a good lube is worth it it make sure it is not sticking in its travel and allowing slip after actuation. A Link to comment Share on other sites More sharing options...
Liamo Posted February 11, 2012 Author Report Share Posted February 11, 2012 Slave cylinder was indeed full of CackTM , Job is now jobbed it seems. Thanks folks! Link to comment Share on other sites More sharing options...
kwakbiker Posted February 12, 2012 Report Share Posted February 12, 2012 Glad its sorted and a simple fix too Link to comment Share on other sites More sharing options...
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