Clutch seems to slip when shifting at full throttle?

[mrdrprof]

When I give my bike full throttle, it will accelerate just fine. But after getting back on the throttle after shifting the RPMs seem to just slowly drop and then pick back up again instead of just immediately going down. Could this maybe be a clutch that's too loose? I recently adjusted my clutch using the screw behind the little plate on the left side (loosening everything then turning the screw till I feel resistance, then backing it off a quarter turn and then setting the free play and where it grabs using the other adjusters). The bike has almost 21k miles on it so I don't know if the clutch would be toward the end of its life. The bike still shifts fine under normal and semi-hard acceleration

[mr72]

Mine does that too. 22.8k miles. Watching this thread.

[yamahonkawazuki]

while you were in there, what did the friction plates look like? were they kinda glazed over? but you also say pretty much its fine under full accel. but slow to go back down (revs)?
got a question , when idling if you snap the throttle, 0 to wfo and relsease, does it immediately go back to 0 or does it hang up a bit then?.
Aaron

[J_Walker]

Go 30Mph pull clutch, shift to 6th gear, Rev high, dump clutch [no way you're doing a wheelie I promise] if the RPM stay's high. or hang before falling, the clutch is slipping.

[ajensen]

There is a recent thread about what kind of oil to use. The wrong oil can cause the clutch to slip. You may have to get new friction plates.

[gsJack]

From old post of mine:

Never saw a 10w-40 oil that wasn't suitable for a GS, the energy conserving oils are lower viscosity ones like 10w-30, 5w-20, etc that are marked with this donut symbol, don't use with wet clutch:



I like the 15W-40 heavy duty oils like Shell Rotella T, Mobil Delvac, etc for the GS.

[gsJack]

Go 30Mph pull clutch, shift to 6th gear, Rev high, dump clutch [no way you're doing a wheelie I promise] if the RPM stay's high. or hang before falling, the clutch is slipping.

I always did it the old fashion way like we did with cars 60-70 years ago, hold both bike brakes tight, rev engine to about 3k rpm in 1st gear, and release the clutch slowly and it should kill the engine without slippage.  Clutches on both my GSs were still good at 80k (97) and 100k (02) miles.

[mr72]

Go 30Mph pull clutch, shift to 6th gear, Rev high, dump clutch [no way you're doing a wheelie I promise] if the RPM stay's high. or hang before falling, the clutch is slipping.

I always did it the old fashion way like we did with cars 60-70 years ago, hold both bike brakes tight, rev engine to about 3k rpm in 1st gear, and release the clutch slowly and it should kill the engine without slippage.  Clutches on both my GSs were still good at 80k (97) and 100k (02) miles.

Yeah my clutch tests good the "old fashioned way", but in higher-gear shifts (3-4, 4-5, 5-6) if you rev it between shifts up to like 9K and then release the clutch it will slip a little at the higher revs and find its way back down.

I am guessing at almost 23K my clutch is just somewhat worn.

[gsJack]

http://img.photobucket.com/albums/v443/jcp8832/GS500clutchadjustment_zps58ca4ce8.jpg

[mr72]

BTDT with clutch adjustment. No change on my bike.

[mrdrprof]

while you were in there, what did the friction plates look like? were they kinda glazed over? but you also say pretty much its fine under full accel. but slow to go back down (revs)?
got a question , when idling if you snap the throttle, 0 to wfo and relsease, does it immediately go back to 0 or does it hang up a bit then?.
Aaron

I didn't have the bike apart to look at the friction plates. I had the little plate off that covers the clutch adjustment screw. But no, the revs don't hang when I twist the throttle. When I get back on the gas after shifting at full throttle the revs go down slowly for about a second then start to climb again. I recently changed my oil but it did this before I changed the oil. I used just regular penzoil 10w-40. Not sure what oil was in there before because I got the bike pretty recently

[mr72]

"regular Pennzoil 10W-40" may be part of your problem. Ordinary automobile oil may be to "slippery" for MC use.

[mrdrprof]

"regular Pennzoil 10W-40" may be part of your problem. Ordinary automobile oil may be to "slippery" for MC use.

Well it did this even before I changed the oil but I don't know if the previous guy used a similar oil. The bike has 21k miles on it so I'm not sure if my clutch pack could be getting worn out or not. Will it hurt the bike at all to keep that oil in there till the next oil change? I've only put about 30 miles on the new oil

[mrdrprof]

Go 30Mph pull clutch, shift to 6th gear, Rev high, dump clutch [no way you're doing a wheelie I promise] if the RPM stay's high. or hang before falling, the clutch is slipping.

Tried this. The rpms go down pretty slow so it seems like it's slipping a little but it's not too bad

[ajensen]

I'd keep the oil in for the next 1,000 miles or until the end of the riding season. I'd take it easy on the clutch--no speed shifting. Then, I'd put in new friction plates and springs, a new primary gasket, and the correct oil. I don't think the automotive oil will hurt anything in the engine or transmission, but others may want to weigh in.

[Joolstacho]

It's the 'friction modifier' additives that most car oils have in them that kill bike clutches.
Use one without the additives, like oils specifically for bikes.