guzzi323 Posted January 16, 2005 Posted January 16, 2005 Hi, My Scura's clutch started slipping quite suddenly. One night it was fine, the next morning it was very easy to get it to start slipping. The last time it worked, I rode in a very heavy downpour for about 30 mintues but I can't imagine that having anything to do with it. The friction plate is less than 2k miles old and peeking in the timing plug hole it all looks correct. It feels like the clutch is out of adjustment (i.e. it grabs at the very end of the lever travel) but seeing as it's hydraulic I'm at a loss. I tried bleeding the system until nice fresh fluid was coming out the slave cylinder but it's still the same. I've also backed out the adjuster screw on the lever itself to be certain the master cylinder piston had play. My next move is to remove the slave cylinder and check that it can retract freely but I believe that involves removing the swingarm and probably the rear of the frame as well. If anybody's got somthing else to check before I rip it all apart, I'd love to hear it. Thanks, johnk
Guzzirider Posted January 16, 2005 Posted January 16, 2005 I am sure that some of the more mechanically minded posters on this forum can give you some better advice than me, but the 2 occasions I have suffered clutch slip on Guzzis have both been due to a leaking engine oil seal allowing oil to contaminate the dry clutch. If you look at the lower rear of your motor and notice oil leaking then that may be your cause. Good luck with getting it sorted. Guy
Guest ratchethack Posted January 16, 2005 Posted January 16, 2005 John, this is a bit of a puzzler. A couple of thoughts: First, it appears that you may have serviced the clutch, since you said the "friction plate" has 2K mi. Do you mean that you had a new clutch disk or disks (1 or 2 disc clutch, it matters not) installed, or that you had the flywheel and/or pressure plate re-surfaced, or do you mean that the bike itself has 2K mi? In any case, either clutch wear to the point of slipping, or main seal leakage enough to contaminate the clutch to the point of slipping would be highly unlikely for a late-model bike - unless you've put an extraordinary number of miles, and/or truly abusive miles on it. In this case, you might have had clutch replacement service....? But then, any point of potential failure is always possible... From what you've said, it appears that you've got full clutch engagement. If at full extent of lever travel, the clutch doesn't slip at all, this means that there's nothing wrong with the clutch assembly, and that it isn't contaminated. In this case, you've reduced the potential source of the problem to a matter of proper adjustment of the hydraulic control. The problem has to be at either the master or the slave cylinder and there's no adjustment at the slave end. I'd start with another re-check of the lever adjustment wheel on the handlebar lever to make sure that you got it dialed back to the correctly adjusted position. If you're enough of a contortionist and you have small enough hands & arms to successfully bleed the clutch , you can just as easily remove the clutch slave cylinder for inspection. No need to remove the swing-arm. Just back out the 3 allen screws around the periphery of the slave cylinder, and it can be drawn straight back and out. Upon inspection, (ain't much to inspect here) if all looks well, I'd be at a loss at that point . Good luck :!:
pete roper Posted January 16, 2005 Posted January 16, 2005 I posted my thoughts on this in a reply on WG but I'll copy 'em here if people are interested. Unless there is a discernable leak between the bell housing and the block or it's dripping from the drain vent underneath I'd say it's unlikely to be a leaking seal on the pushrod but I'm not sure what sort of seals are used on the six speed pushrod???? Rear main seals very rarely blow and when they do you're in 'Blurt City' territory, the thing would be sitting in a pool of oil. My guess is still that if you use the clutch hard the poxy sintered bronze plate has gone tits-up. Pete
guzzi323 Posted January 17, 2005 Author Posted January 17, 2005 My guess is still that if you use the clutch hard the poxy sintered bronze plate has gone tits-up. Pete 41125[/snapback] Well the plate is gone. In less than 2 thousand miles since I replaced it. :!: The mating surface in the ring gear looks practically perfect and the pressure plate looks very good but not quite as nice. So I guess I'm looking at another friction plate and some machining. When new the plate was .240" thick and it's now about .170". It's used about half the available friction material however. I also noticed while I was pulling everything apart that the piston in the slave cylinder was pushed as far into the slave cylinder casting as it could go. It seems as though the last half of the clutch material is unusable because when the clutch wears to the point it's at now the clutch actuator won't allow it to engage fully. I can't believe the plate wore out so quickly. Almost all the miles have been during my 15 mile commute to work. I got 22K out of the first plate and it hadn't even started slipping yet (though it was only about .005" thicker that the one I just took out.) At this point I think I'm going to get a fiber clutch plate and see if I can get more life out of it. If it's got the same thicknesses as the one I took out I might space the slave cylinder back .050" or so to see if I can get more life out of it.
Guest rrbasso Posted January 17, 2005 Posted January 17, 2005 I can't believe the plate wore out so quickly. Almost all the miles have been during my 15 mile commute to work. I got 22K out of the first plate and it hadn't even started slipping yet (though it was only about .005" thicker that the one I just took out.) Wow this just does not make sence to me ? how can it where out so fast ? I am very angry
emry Posted January 17, 2005 Posted January 17, 2005 Well I just measued my, since I had it apart.... 0.2225" or 5.65mm for the rest of the world. I have a little over 9k miles. As much as I hate to say it it would seem some error in assembly was made. This allowed the clutch to slip slightly while you were riding. Or you had a clutch plate made of caulk??? Maybe a adjustable pushrod would be in order to get little more life???
guzzi323 Posted January 17, 2005 Author Posted January 17, 2005 Well I just measued my, since I had it apart.... 0.2225" or 5.65mm for the rest of the world. I have a little over 9k miles. As much as I hate to say it it would seem some error in assembly was made. This allowed the clutch to slip slightly while you were riding. Or you had a clutch plate made of caulk??? Maybe a adjustable pushrod would be in order to get little more life??? 41258[/snapback] This affirms my suspicion about my quickly wearing clutch. I'm becoming more convinced that the combined length of the clutch pushrod, bearing and such are just a wee bit too long. Keeping my my clutch slightly disengaged. I've ordered my replacement clucth and upon assembly I'm going to install everything and work the clutch a few times. Then I'll pull the slave cylinder and check to see how far from fully compressed the piston is in the housing. I suspecty there will be very little room for the piston to receed as the clutch wears. If so I'll space the slave cylinder off the back of the tranny case. Emry, I saw that you posted on my previous thread about the loose flywheel bolts. Glad you caught it in time. Maybe we have an answer to the exploding clutch mystery! I know I'll sleep better. johnk
Baldini Posted January 18, 2005 Posted January 18, 2005 JohnK, What plate you putting in? Not all the same. I remember on Tontis there were some plates (for racing) you could get hold of that'd be toast in very low miles. KB
guzzi323 Posted January 18, 2005 Author Posted January 18, 2005 JohnK, What plate you putting in? Not all the same. I remember on Tontis there were some plates (for racing) you could get hold of that'd be toast in very low miles. KB 41280[/snapback] I'm putting in the RAM bronze replacement clutch. Both are made by Surflex and appear identical. I thought about replacing it with a fiber plate but decided to stick with bronze and check out my theory on the slave cylinder. If it goes out again in an unreasonably short time, I'll be putting in the fiber plate. At least I am getting good at this whole tranny pulling business. johnk
Baldini Posted January 18, 2005 Posted January 18, 2005 John, I think it was sintered metal ones (for racing use) that wore out real quick on Tontis. Think they were bronze. Lasted no time. If your supplier can't advise, Would Dave Richardson/Moto International be able to tell you? Seems like a lot of work to have to do in another 2K miles if plate is wrong. KB
pete roper Posted January 18, 2005 Posted January 18, 2005 John, I think it was sintered metal ones (for racing use) that wore out real quick on Tontis. Think they were bronze. Lasted no time. If your supplier can't advise, Would Dave Richardson/Moto International be able to tell you? Seems like a lot of work to have to do in another 2K miles if plate is wrong. KB 41308[/snapback] I strongly advise against using another sintered bronze plate. Whether these failures are consistent or it is a case of poor quality control on some items I don't know but I do know that, generally speaking, fibre plates are better. I've said as much on WG but I'll reitterate it here but at the end of the day it's the man's choice and it may work out fine. Pete
emry Posted January 19, 2005 Posted January 19, 2005 Pete, I am just curious. Why the thoughts about the metal vs fiber plates. Do you think that a fiber plate would hold up in a single plate system that is "abused". In the auto industry metal was for heavy duty racing app's, fiber for street or longer life. The metal had a tendency to chew up flywheels and pressure plates. Many now have moved to ceramic design that seems to combine the forgivness of fiber with the bite of metal.
pete roper Posted January 19, 2005 Posted January 19, 2005 Mainly down to my experiences with the sintered bronze twin plate units available in the early '80's which were awful and wore out in next to no time and my mate Dave's Transkontinental unit that used a bronze plate that wore out in about a week!!!!! We use bog-standard fibre plates in our race bike without problems I just tend to think Bronze is a recipe for rapid wear for little or no gain. Pete
jrt Posted January 19, 2005 Posted January 19, 2005 The sintered plates in the RAM clutches seem to hold up ok. I know several people with many thousand miles on them. Don't know much about the bronze dual plate setup. Jason
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