Clutch / transmission - did I break it?

[Hinermad]

I replaced the chain on my '78 GS750 and now the clutch won't disengage. With the the transmission in neutral I can turn the the rear wheel freely, but if I put it in gear and pull the clutch lever the rear wheel will turn only a few degrees in either direction then hit a hard stop.

Last summer when I went to replace the chain I discovered a previous owner had converted it to use 530 chain but used sprockets with the same number of teeth as for the original 630 chain. So the sprockets were a smaller diameter than they should have been. I bought new sprockets with the correct number of teeth, but in the process of trying to replace them I couldn't get the nut for the engine sprocket loose. I ended up turning the drive shaft counterclockwise instead of the nut. (That nut is right hand thread, right?)

I decided to bail out and continue using the smaller sprockets for now. It ran before this way, although I think it takes a higher RPM to make a given speed.

But after I put it back together, I noticed the problem above - the clutch won't disengage. It seems like the clutch release does try to push on the pushrod when I pull the lever, by a fraction (maybe an eighth?) of an inch. Is that a normal amount? When I try to push the pushrod by hand it doesn't move, but I hope that's just because it has a strong spring.

The pushrod itself moves back and forth freely by about a half inch. In the parts drawing on Babbitt's it looks like it should have threads on the inner end but I can't get it to thread into anything. Is this normal? I see the original rod has been superseded by a different part number, but I haven't been able to find a drawing for it.

Any suggestions? Did I break something by turning the drive shaft?

One other thing that might (I hope) affect this is that while I had the cover off to get at the engine sprocket, wasps tried to build nests in some of the screw holes. I tried to clean them out before reinstalling the cover but it's possible I didn't get it fully seated. Could that cause the clutch release to not push the pushrod far enough to disengage?

[Suzukian]

If you had debris in the hole, the case would not have sealed. If you used the larger thicker chain, it could be hitting the case. If that is not the case, you just made have go go through the clutch adjustment procedure. Loosen the cable up by the grip so that it is slack, then adjust the throw out pit so that it just touches, then back out a little. After that, then adjust your cables so they are not too tight or too loose. If you could push that push rod in by hand, either you're the "Hulk", or you would have some serious other problems. You should not be able to budge it.

I just put a front tire, and a bunch of other cr@p to bring my .83 GS750ES up to snuff. I adjusted the clutch, and when I engaged it, I found that I had not left enough slack, and the clutch was not disengaging all the way. The clutch itself was adjusted properly but I had the cable adjustments too tight, pulling on the clutch lever. Sh*t happens.

[unfocused]

I ran into an issue with my 77 GS750 - 13 tooth sprocket - if i didn't space it out, the chain rivets (poss master link) would hit the trans case - if I spaced it out, the nut would hit the clutch cover. I found another shorter nut for this but haven't tried. I would suspect you're facing the same issue. Look in through the rear of the sprocket cover.

I took the sprocket off and am running a 15T for now. That 13T is going to fit LMAO...

One thing to look at is the master link itself. Those rivets tend to be long.... might reverse it.

The advantage of a smaller sprocket is quicker launches - horrible top end rpm's

Let me add - Make sure all of your spacers (#15) and rubbers (#14) are in place. Rubbers keep the chain lube off of the engine and your scoot can be run without them. Spacers must be in place!!! Sorry for the small picture... Suzuki Parts House has a good look up. I just ordered several of the bushings because of my issues. Go to a marine dealer for them, they can get them cheaper and they still use the same bushing.



750 clutch cover.png

[Nessism]

It sounds like the clutch is not releasing.

The release mechanism is attached to the sprocket cover. The sprocket cover doesn't seal oil, it just covers the chain and holds the release mechanism. If the sprocket cover is not seated against the crankcase, the release mechanism won't be properly pushing the clutch release pushrod.

I'd pull the sprocket cover back off, and flush out the holes in the engine case to remove the insect debris. Get a couple of cans of brake cleaner, and put the nozzle in each screw hole and blast the crud out. Do it several times as needed until the holes are clear. Then reinstall the cover, and go through the clutch adjustment procedure as specified in the factory service manual.

Oh, and I'd get that small sprocket off too. It's not good to run a tiny sprocket like you are. The chain can slap against the swingarm, and the small diameter will wear out the chain faster than necessary.