Another clutch not working

[Pearson]

'78 GS750
Avg. Air temp.: 40-45F
New superbike bars (much lower than stock) cable moves freely
No oil from July-Sept., Fresh oil in Sept.

I've been searching for about 3 hrs. now on clutches....
Thanks to "The Forum" I was able to get my carbs to stop leaking. I was so happy I was dreaming about finally riding the thing!

I got it started, warmed up a little bit, and put the bike in first. Sure enough bike lurches forward and dies. The third time this happens I decide to adjust the clutch.

Now she's on the center stand. I follow the manual, turning in the adjuster on the handlebar and on the case. I loosen the lock nut and after removing the cover, adjust the screw with the slot to snug and back off 1/4. Complete the procedure, start the bike, pull in the clutch (which for now feels normal), and drop into first. Rear wheel turns, but I can't stop it with my foot suggesting clutch just isn't working. Back to neutral, wheel stops of course. I try this several more times and as I'm turning the slotted screw adjuster, all the sudden all resistance disappears as if there's nothing there.

I was able to continue messing with the adjustments and got tension back but then lost it again. Regardless, nothing I tried would get that rear stopped...as if the clutch wasn't doing it's job. What's going on here?

[t3rmin]

I've never been able to adjust it to the point where the rear wheel won't turn at all with the clutch all the way in without the clutch slipping. It's normal to have a little bit of drag, but you *should* be able to stop it with your foot. It's only enough drag to spin the wheel a bit when the bike is on the centerstand, not really pull the bike forward when it's on the ground. The exception is when the bike is cold. When cold, these clutches like to drag quite a bit.

When I first got my bike and tried to adjust the clutch I also thought it was messed up exactly like you're describing (a major "ARGHH!!" moment!), but I just hadn't got it adjusted right and didn't realize a certain amount of drag was normal.

Make sure your bike (including your tranny/clutch areas -- they take longer) is good and warm then adjust the cable until you have 2-3mm of play in the handlebar lever before it engages. Then squeeze the clutch all the way in, put it in 1st gear, and have a go at stopping the wheel with your foot (while on the centerstand of course). If that doesn't work, tighten it up a bit (with the adjuster on the handlebar lever). With my non-OEM clutch the usual 2-3mm play is too loose and I do have it adjusted a bit tighter.

In the morning when the bike is cold, be sure to hold the brake on or at least brace yourself before shifting into gear. The first couple shifts will be a bit hard until it warms up. That's totally normal operation, especially if you have a thicker oil. It's also been suggested to work the clutch several times before riding to help get the plates un-stuck.

[Billyboy]

Seized.

Get it running and spinning on the stand. Squeeze clutch and stomp on rear break. Keep the throttle up. Should break loose.

Take precations against tip off, or over.

[t3rmin]

Ahh yes, good call. At that point might you want to just pull the plates out and clean 'em/make sure they're all spinning freely? It's *super* easy to pull the clutch apart. Just put the bike on the side stand, let the oil drain over to the other side, pull the cover off (after pulling the actuation arm off the splined shaft), and yank the disks out and inspect 'em. Getting into the clutch is easier than pulling the valve cover off.

[Pearson]

Seized.

Get it running and spinning on the stand. Squeeze clutch and stomp on rear break. Keep the throttle up. Should break loose.

Take precations against tip off, or over.

Oh, I get it. I figure after reading all the other posts on clutches, it can't be anything major since it was working fine back in July. I'll give that a try. Thanks.

[Pearson]

Ahh yes, good call. At that point might you want to just pull the plates out and clean 'em/make sure they're all spinning freely? It's *super* easy to pull the clutch apart. Just put the bike on the side stand, let the oil drain over to the other side, pull the cover off (after pulling the actuation arm off the splined shaft), and yank the disks out and inspect 'em. Getting into the clutch is easier than pulling the valve cover off.

I think I saw a prior post of yours saying it was very easy to do..but I've never done clutch work and haven't even learned what an actuation arm is yet. I won't bother you with those details (yet 8-[ ) as I have to do more homework with my Clymer before digging in. Like everything else on this bike, a good cleaning is in order.

Thanks for the help.

[t3rmin]

I think I saw a prior post of yours saying it was very easy to do..but I've never done clutch work and haven't even learned what an actuation arm is yet. I won't bother you with those details (yet 8-[ ) as I have to do more homework with my Clymer before digging in. Like everything else on this bike, a good cleaning is in order.

Thanks for the help.

Naw, that's just me trying to sound smart. I'm just talking about the post and the arm that pops out of the top of the clutch cover. It's the same spot you've been adjusting your cable at.

Just pull that arm off the shaft by taking the bolt that crimps it on all the way off (all the way off, not just loose). Just leave the cable attached to it and tuck it out of the way for now.

*EDIT* on your bike this stuff may be under a cover that's attached to the main clutch cover (a cover on a cover). But if you've been adjusting your cable, you're already there.

Then just remove the (8 or so?) bolts holding the clutch over on (bike on sidestand!) and remove the cover (may need to bang on it a little bit with something soft to break it loose). Then remove the clutch basket retainer plate (very obvious what to do at this point) by backing out the spring retainer bolts, and then pull out all the discs. You'll have friction discs and steel plates alternating.

Clean 'em off with your favorite cleaner, wipe 'em dry then rub or soak 'em in motor oil, then put it all back together (torquing the spring retainer bolts to 8ft/lbs, if I recall). You might want to rub a little RTV sealant on the gasket sealing surface with your finger before re-using it (I did). Not too much RTV, though, just a thin coating rubbed on with your finger, and only on the part that actually seals against the metal.

Seriously, the clutch is one of *the* *easiest* things to get to on your bike. Dive in!

[Billyboy]

Onliest thing I'd add is to keep the disks in the same order.

Also.

DO NOT OVERTORQUE SPRING BOLTS!!!

Aluminum breaks really easy. Especially on a 27 year old bike.

[t3rmin]

Onliest thing I'd add is to keep the disks in the same order.

Also.

DO NOT OVERTORQUE SPRING BOLTS!!!

Aluminum breaks really easy. Especially on a 27 year old bike.

Was I on with the 8ft/lbs? Was just from memory...

[Billyboy]

Was I on with the 8ft/lbs? Was just from memory...

Perty darn close. Manual says 8 - 9.5

I only emphasized because. "Just one more quarter turn..." turns into "Oh Phuck!" really quick.

[t3rmin]

Perty darn close. Manual says 8 - 9.5

I only emphasized because. "Just one more quarter turn..." turns into "Oh Phuck!" really quick.

Hehe, yep. I just replaced my clutch and luckily a little voice in my head said "you'd better check the torque specs on those spring retainer bolts" before I put 'em back on. I have a nasty tendency to forget about torque...

[RobGS850L]

I know my 850 on a cool morning I put it in gear and she takes off whether or not the clutch lever is pulled in. Once warmed up she's OK. I hear thinner oil could help but it only lasts for a few minutes so I'm not frettin' over it.

[Pearson]

Well there's a whole lot of very good information in this thread already. Nuff' prolly to get me in trouble but I'm sure you guys will help me out when I get there. I'll work on fine tuning the carbs while she warms up and before I tackle the clutch work.

I really just want to be sure the bike is pretty solid and worth puttin' on the paint job I have planned. Tins are due to go to the shop Monday.

[Pearson]

Seized.

Get it running and spinning on the stand. Squeeze clutch and stomp on rear break. Keep the throttle up. Should break loose.

Take precations against tip off, or over.

It's a little warmer today, around 60. I followed the above and worked like a charm. \\/ Even got the clutch adjusted. Once I adjusted carbs, plugged a vacuum port (I have a new Pingel) and tuned the carbs a little bit I took her for a spin around the block.

Thanks all.

[t3rmin]

Glad you're ridin'! I'd still pull that clutch apart when you have a chance, 'cause who knows if you've broken loose all of the plates or if some are still stuck together...