Clutch Drag.
 

Hi,
I have a 1994 xt 600e. The chassis number is JYA3WRT08NA****** and the motor is a 3AJ. The clutch cable is on the left hand side of the engine. Since rebuilding the engine and gearbox I have had a lot of trouble with the clutch. When the engine was cold the bike would change gear smoothly and neutral is was easy to find. When it got hot the clutch wouldn't clear and dragged. You could feel the bike creeping along even when the clutch was pulled in. Neutral was impossible to select and gear changing was rough.The hotter it got the worse it got. I tried EVERYTHING to sort this out. New cable, different oils, endless adjustment of the cables and rod inside the engine. I even sent the whole clutch assembly to a specialist who builds clutches for drag bikes and he said it was all good. By this time I had pulled the right hand casing on and off five times and was ready to sell or burn the bike!!
I mentioned this problem to an old british bike mechanic who did some machining work for me and he reckoned it was the clutch friction plates. His theory being that if the plates were old and had been run in lots of different types/grades of oil they could get sticky when hot even though they looked ok. So, I roughed up the metal clutch plates with 80 grit emery paper, fitted some genuine Yamaha friction plates and a new actuating rod (the one that runs through the middle of the motor. The spiral ends were scuffed and worn) and now the clutch is now perfect, no drag, no sticking, smooth gear changes and neutral is easy to get even when the motor is good and hot.
I would also like to recommend Loctite 518 as an engine gasket sealant. I have been using it for years and it is just brilliant for stopping leaks.
Cheers Paul

Thanks for this. I have the same bike and a similar problem, although not as severe. The clutch drags slightly at all times (cold and hot) and adjusting for a clean gearchange means that the clutch starts slipping at higher throttle openings. It isn't bad enough to tear the thing down just yet, but I am planning a new set of plates at some point. A local mechanic who does a lot of work on competition dirtbikes told me that a frequent cause of this issue is slightly warped metal plates, and advised me to check all of them with a straightedge when I put the new cork plates in.

Glad to know it's not just me, anyway.

friction plates are in most cases a friction material just bonded to a steel ring and its the adhesive used to do the bonding which eventually gets broken down and makes the plate tacky :innocent:

richard dont forget to give your new friction plates a good soak in oil before fitting them it will extend the life of the clutch :thumbup1:

Heh, thanks. As I understand it, the soaking in oil is not to extend the life of the plates (which will be soaked in oil in a few hours anyway after fitting) but to make sure that any adjustment stays correct and is not spoilt by the plates swelling after installation. Looked at another way, what you are doing is pre-swelling the plates, rather than just soaking them.

But it's a good practice, for whatever reason.

once the plates are installed they will be under constant pressure so will not be able to soak in oil:nono:

if the plates are not fully soaked before fitting it may cause some area's to by left dry and will make that area more prone to heat and un-even pressure and that shortens the life of a wet clutch :(

Paul, thanks. Great info.

clutch drag
 

Bugger!! Didn't pre-soak the plates. http://www.horizonsunlimited.com/hub...milies/sad.gif Oh well if the problem re-occurs I will know what to do. Interesting that it is the adhesive that breaks down, makes complete sense. Could be a time related problem as I think that my clutch plates were original and would have been soaked in oil since the bike was built in 1994.
Paul.

paul if you want to ensure you get some oil round the clutch after installation run the motor till its up to temperature so the oil is thinner, take all the slack out of the clutch cable then use something like a cable tie to strap the clutch lever to the bar then run the engine for a while the hot oil should then get into the plates :thumbup1:

just remember to put the slack back in the cable before using the bike :innocent:

Makes sense, thanks.