Clutch suddenly slipping

[Wild-Bill]

I realized the other day that the last time I changed the oil I grabbed the wrong stuff. The JASO-MA oil I put in there was ASI-SM rated. Not a good thing although I've run Castrol GTX in the past in several different bikes without any trouble at all.

I've been getting some pretty heavy clunking going into 1st and neutral has been hard to find until I shut down so it's time for another oil change anyway. I rode the bike the 10 miles to Autozone and back to pick up the oil and get the engine warm and then had to pop over to the store on base for a couple of things so I just kept going. Normal ops so far. It's about a half mile from my house to the base gate where I had to stop and show my ID. Pulling away, the clutch seemed like it was slipping a bit although at the time I thought I was just getting cold fingers. Another 1/4 mile later I shut down to refuel, started her back up to move to a parking spot and shut down again while I went inside. I came back out and it's slip city the whole way home. Classic symptoms including the bike not wanting to start moving and not doing much of anything when I rev the engine. Same thing no matter what gear I'm in.

It's possible that the clutch started slipping because of the ASI-SM oil but I've never heard of a clutch going from good to bad that suddenly. Anyone have any insight? Is it likely that washing the plates and changing the oil will fix it or am I screwed and buying new friction disks? Is it more likely that my (probably) 20 year-old clutch just decided a 3-day weekend with great weather is the perfect time to disintegrate?

[05RedKat600]

Is it hard to shift still too? Personally, I'd do an oil change with the right stuff and see what happens. If it works, that's a cheap 12 dollar fix vs hundreds. Then again, it IS a 20 year old clutch, and things always work right until they don't.

May want to check the adjustment on the clutch itself too. I've seen the nuts come loose and muck with adjustments before.

[Wild-Bill]

12 dollars?! Where do you buy your oil? I paid $4.99/qt for 5 quarts of Castrol motorcycle oil at Autozone tonight.

Not much in the way of adjustment for me. The 1100 has a hydraulic clutch.

[05RedKat600]

Ah. Was assuming this was the 750. My oil for my FZ6 is 4 bucks a quart x 3 quarts = 12 bucks. Forgot the Kats take more.

Hydraulic clutch...checked the fluid lately or possibly the slave cylinder is sticking? Add any new aftermarket levers lately? If not, it just might be your clutch finally gave up the ghost.

[arsenic]

things always work right until they don't.

Sounds familiar.

[05RedKat600]

Sounds familiar.

Yeah, I stole that. It's so damned true. It's like someone that puts oil in there car, and then it won't start. They think that putting the oil in killed it.

[Wild-Bill]

Ah. Was assuming this was the 750. My oil for my FZ6 is 4 bucks a quart x 3 quarts = 12 bucks. Forgot the Kats take more.

Hydraulic clutch...checked the fluid lately or possibly the slave cylinder is sticking? Add any new aftermarket levers lately? If not, it just might be your clutch finally gave up the ghost.

The 750 takes 5 (4.8) quarts, too. That's the price you pay with an air/oil cooled engine.

Rebuilt slave and MC this summer. Still have the OEM levers. Low fluid would have the exact opposite effect--failure to release, not failure to engage. It's good in any case.

I suspect it's just that the clutch decided a 3-day weekend with great weather that falls between school semesters is a perfect time to poop the bed. I'm just grasping at straws here because I know exactly what's going to happen. I'm going to order up the new parts and about the time I get them installed the weather's going to go in the toilet again. It'll be months and months of work, school and the kids eating every minute of nice weather and then as soon as I've got a day I can break free for a few hours the weather will suck. It's been like that all summer. FML.

Yeah, I stole that. It's so damned true. It's like someone that puts oil in there car, and then it won't start. They think that putting the oil in killed it.

Nah, it's forgetting to re-install the drain plug that does that!

[Wild-Bill]

Well, I got it all apart today and went wild with the calipers. Nothing's delaminated, friction disks are all thicker than minimums, springs are 2mm longer than the minimum and nothing's broken. The only thing I found that wasn't quite right is that the spring bolts didn't seem like they had the 8-9.5 ft-lbs the FSM calls for. Maybe a little loose although it's pretty hard to tell when things are that light. I'm hoping it's that or maybe just the oil.

I got everything apart, sprayed everything down with brake cleaner, scrubbed the friction disks on the floor and I've got them soaking in fresh oil now. I'll get it all back together in a bit and see what's what. Maybe I'll get lucky.

[steves]

How old were the plates in the first place?

[Wild-Bill]

Not sure. I bought the bike last fall so at least a year old. I had been thinking they were probably original equipment but the cover came off really easy and the gasket is still very flexible (came off whole) so I'd suspect that the clutch has been replaced at least once and not that long ago. I'll have to call the PO and see.

The wear limit on the springs is 38.5mm and they all mic'ed at 40mm. Wear limit on the friction plates is 2.22mm and they were all around 2.60. The thinnest was 2.56mm.

I went ahead and put everything back together this evening just to have one of the spring bolts snap on me. I got it out no problem with a pair of pliers but the only bolts I've got on hand the right size and length are grade-4. Original is grade-7 so it's sitting until tomorrow when I can get my hands on four new bolts.

[buffalobill]

What about the last 500 miles?

I have a 1982 GS1100G, and the clutch slips in 3rd when I'm really pushing it hard. But for casual riding it seems OK.
I got new friction rings and springs. but no need for down time when the weather's so GREAT! I can do that later, on a rainy day.

Has your's been slipping some when pushed hard in the last 1000 miles?

Bill

[Wild-Bill]

No slipping at all (that I noticed) until last night. Then it went from fine to limping the 3/4 mile home in nothing flat.

[rexazz2]

check the oil level as well
The first oil change on my B12 was over full and it caused the clutch to slip at high speed full throttle
I drained it to the proper level and it has been fine since (5000km)

[Wild-Bill]

Well, I changed the oil (level was in the middle of the sight-glass before) along with going after the clutch pack. I got it all back together this afternoon and took it out for a test ride. Felt great coming out of the driveway but a couple of blocks later it felt like it was slipping a bit. Got on it a couple of times to see if I was imagining it and it got rapidly worse. I ended up pushing her home from about 1/2 mile away--down a hill, back up the hill, lost my footing for a moment and dropped the bike onto the right side. Right on top of the helmet which I'd hooked on the helmet lock to keep it from getting knocked around.

Now I need a new clutch pack, a new helmet and a new turn signal. Not a good day at the Wild-Bill household. Anybody got an OEM turn signal for an 1100?

[scottynoface]

Well, I changed the oil (level was in the middle of the sight-glass before) along with going after the clutch pack. I got it all back together this afternoon and took it out for a test ride. Felt great coming out of the driveway but a couple of blocks later it felt like it was slipping a bit. Got on it a couple of times to see if I was imagining it and it got rapidly worse. I ended up pushing her home from about 1/2 mile away--down a hill, back up the hill, lost my footing for a moment and dropped the bike onto the right side. Right on top of the helmet which I'd hooked on the helmet lock to keep it from getting knocked around.

Now I need a new clutch pack, a new helmet and a new turn signal. Not a good day at the Wild-Bill household. Anybody got an OEM turn signal for an 1100?

Ouch man, sounds like it soaked into the cork...no need to buy new steels if they're still good.