Slippery Clutch

[sam_cg_cook]

Hi,

Having some clutch slips on my 1980 special, particularly in 3rd, 4th, 5th gears when I roll on it... somewhere around 4k-6k rpm, usually around 6krpm though. Thinking about redoing the clutch this summer sometime, and my question is...

will this problem be solved by replacing the friction plates, clutch plates, compression spring, and pressure plate #2 ?

do I need to go further than this?

do less than this?

I'm not afraid of tearing into things, and can follow manuals quite nicely... but I lack the experience that some of you folks have, so I definitely appeciate the help.... past, present, and... of course... future.

Thanks,

Sam Whitcomb

[uk1.1s]

Slipping clutch

Sam,

Don't know if you've had a crack at adjusting the clutch - but if not that would be my advice.

If you haven't got a repair manual the drill is very simple - there is a circular plate in the centre of the RHS engine casing held on by two screws. You can take this off without any fear of oil pouring out and this reveals the clutch adjustment screw and locknut on the end of the clutch rod.

Loosen off the clutch cable up at the lever on the bars and then undo the locknut you revealed down at the other end. Correct clutch adjustment is when you screw the adjuster screw in until you feel a bit of resistance (as it starts compressing the plates) and then back off 1/4 turn. Lock up the screw carefully with the locknut, keeping the screwdriver on the adjuster otherwise it will move as you lock it up. Don't forget to set the clutch lever at the handlebars back with just a little bit of play before you feel the cable start to pull. There's probably a Yamaha value for clutch play at the lever, but it's easy to do it by feel.

After that if you still have clutch slip - - then new plates are the answer usually and should solve your problem. I'd advise on standard clutch springs if you are going to change them too as the high performance ones make the operation a little stiffer - which is a trade off if you drag race or something, but not really needed for the road.

Hope the adjustment solves it for you - but don't worry, fitting new plates isn't too complicated

[sixtysix]

Have you switched to full synthetic oil? This can cause a marginal clutch to slip, I would try switching back if you have to see if problem goes away. Next I agree with the above, stock friction plates and spring. Next if it is slipping that much right now, you are burning the steel plates inside the clutch, once these warp and discolor, they are junk, extreme heat softens them and causes small metal particals in the oil, also the clutch plates themselves will be disintegrating. DO THE CLUTCH NOW if you are going to do it at all, save your self some engine wear. Last, read the tech tips on the star plate, more than a few of these have been broken by first time clutch replacers, they are a little tricky and must be tightened slowly and evenly or the ears will snap off.

[TopCatGr58]

Hey there Sam,

Like the others stated, check the type of oil, and do the clutch lever adjustment on the engine. If still slipping, replace them now so that you WON'T hopefully have to replace the steel plates. But if it's slipping in the lower gears as well as the higher gears, and you haven't gone to synthetic oil, and your lever adjustment is correct, then your friction plates are history at least.

Most folks don't have to replace the Pressure plate. Like Gary said, the star plate is easily broken, brittle aluminum...BTDT!!!!! There is a little lip on the edge of the points of the star plate that can sometimes get caught on the shafts of the opposing pressure plate, and that puts undue pressure on the point, that causes it to fracture and break off. You can inspect the steels when you pull them out, and usually some fine emory cloth can buff them to remove mild oil residue/gum from them. There is usually a pattern etched into the surfaces of the steels to keep them from sticking to the friction plates when disengaging the clutch, as long as you can see that pattern and they aren't warped, then you should be able to reuse them.

I got the basic set of plates and heavy duty springs from Dennis Kirk, I don't find the clutch really any harder to pull than before. The "Standard" heavy duty springs aren't that much stiffer IMHO, and help with a good engagement of the clutches. But if you want to, you can get the new steels, they run about $100 for a set, along with $50-60 for the friction plates, and $6-12 for the springs. You can even make your own clutch cover gasket if you really want to save some $. Good Luck.

T.C.

[sam_cg_cook]

THANKS

Thanks, guys, for the replies...

I went ahead and ordered new:
Friction Plates
Clutch Plates
Springs
Clutch Bearing (figure while I'm in there...)
and I have a partial gasket kit that has what I need...

Total for all from local Yamaha dealer: $161...

I have regular oil in the case, and have done the clutch adjustment, so I'm sure that I need to do the plates...

Thanks for the tip on the star plate... I'll watch out for that...

I think I'm going to photograph the whole operation, and maybe put it up in tech tips... sure, it's not a difficult repair... but there are other newbies out there... just like me, that may find it useful.

Sam