Transmission trouble

[Guest]

Had to push my 81 650g home yesterday... Problem started on trip home from work, only a five mile commute. About a mile from house, going around 50 in fifth, engine races as if clutch is slipping. Baby it home, start searching forum for answers.

[Steve]

First of all, make sure the cable is adjusted properly. Sounds like something tightened up there. Might have been a bit too much slack, then caught somewhere when you turned the bars.

If cable is OK, you problem is probably just the clutch springs. How many miles on the bike? If you want to try to get by really cheap , you can put a washer under each spring to shim it up a bit. Best bet would be a new set of springs and a gasket. Probably only about $40 total.


.

[waterman]

After search, figure that clutch springs must have failed, preventing clutch from disengaging fully causing slippage. Yesterday, I fire up bike to go to work, take off figuring I will make it even if clutch slips. Not going to happen, get 1/4 mile down road, no go in any gear. Hop off bike, push bike home.
Today, I tear into clutch to see what maybe trouble. Preliminary inspection shows no obvious problems, plates look fine, basket and hub seem like new. This is not unexpected since bike has only 9k miles. Check spring length, two of six are near minimum length. I have backup in a 650 parts bike in back of garage. Tear into backup bike, everything looks same, pull out springs to replace two suspect ones.
One thing I did notice was that the inner clutch hub would spin even when placed in gear. Checked parts bike and when placed in gear, inner hub would lock up.
My question is what is going on with my tranny? Put bike back together and no go at all. Curious thing is that there is no strange noises or weird interactions with gear shift or clutch. Is it possible that I somehow have broken my transmission or possibly the output shaft? I will pull my rear wheel to check the wheel splines but can't imagine them going that quickly. Any other thoughts as to what is going on?

[chef1366]

See if your counter sprocket slipped off the splines.

[rphillips]

I would think more likely, somewhere in the final drive than the tranny. Can you feel the driveshaft thru the rubber boot? If so, check to see if driveshaft is turning when you turn the rear wheel.

[waterman]

Chef, I am not sure what counter shaft you are referring to?
Rphillips, I will check that when I put the rear wheel back on bike.
Right now with the rear wheel off, I can shift into gear and the final gear will spin in first but not in the other gears. Even in first, if I accelerate it stops rotating. The gear splines to both rim and final gear appear okay.
This transmission has always been a little noisy during gear changes with a definite clunk from one gear to next. Even though it hasn't missed a shift or caught more than a couple false neutrals when I got lazy. Thanks for the replies.

[chef1366]

Sorry, you have a G model. Disregard due to stupidity.

[waterman]

Chef, apologies accepted; beginning to think I am the stupid one with a "g".
Rphilips, just got rear wheel back on, and when rotating tire, I can feel the universal turn in the rubber boot. Thus the propeller shaft from there back is fine. Pretty much think it must be in tranny unless there is some shear pin that broke.
I just can't seem to get over the suddeness of it going fubar. I have had bike for year and half and driven it nearly 2k miles with no real serious trouble. I am a little mad in that I drove it sanely and didn't beat it mercilessly.

[SqDancerLynn1]

Take a very close look at the drive splines on the wheel adapter. Check the beveled drive gear assembly, big nut where the drive shaft bolts- the shaft can break

[waterman]

SqD, I really don't think it is the wheel adapter in that the propeller shaft will turn the universal coupler when the rear tire is rotated. Also the lack of friction or any strange noise when it is rotated makes it hard for me to believe that the propeller shaft is broken.
The way I see it, one of three things are possible. First, in some strange way, the gear shifting forks and linkage has broke and thus even though the gear indicator shows that I change gears it is actually in nuetral. I find this hard to believe since when the bike failed the other day, it failed in all gears.
Secondly, it is possible that physically, I have stripped the transmission or bevelled secondary gears. Again, the lack of strange grinding noises and metallic bits in oil makes this hard to believe. It also seems incredulous since gears don't simply fail without some warning.
This leads me to believe the problem may be after the bevel assembly in the gear case but before the propeller shaft--the large nut that holds that connects the secondary to the universal joint near the swingarm. From the parts diagram, if this nut would loosen and the splines wear through, this condition would prevent bike to move under own power.
The one thing that makes me believe this is that the motorcycle is extremely easy to push, even easier than it was say last week. When it died the other day, I pushed it home in a couple minutes without breaking a sweat. Usually the shaft drive adds considerable resistance when pushing. Granted I was ticked so the push was adrenaline enhanced.
I am still searching for the answers, would like to believe it is something simple. I am not sure I am up to pulling motor and splitting halves to fix though. Would need someone to talk me into (and through) it. Thanks.

[rphillips]

Tranny problems are almost un-heard-of in the GS bikes, especially unmolested low mi. bikes. "BUT" anything can go wrong. When turning the rear wheel, does the inner clutch hub turn at all?? If it does, count hoiw many turns it makes per rear wheel revolution. Then shift up a couple of gears & count again. This could tell you if the transmission is actually shifting or not. Still thinking something between the trans. & the rear wheel.

[waterman]

Rphilips, today I should have some time to check to see if clutch spins as you suggested. I think I will also pull the swingarm off to check where the universal joint connects to the bevel assembly output flange. I think (hope) I will find something apparent there. If not, then it is decision time as to whether I want to pull engine and split cases or start fixing parts bike. Thanks again and I will keep posting results.

[gustovh]

my bet is the splined output shaft fitting on the secondary gear. The shaft just below the nut broke on the secondary gear on my X 82 1000 L. If you spin the spline you get the symtoms described.
V

[waterman]

Gustov, I believe you are correct in that I have lost splines on a secondary shaft. Which shaft in the secondary are you referring to? It is kind of confusing since the output shaft of the transmission connects to one bevel and then the other bevel gear shaft connects to the flange of the universal propeller shaft. I will refer to the former secondary shaft as input and the latter flange coupling shaft as driven. (I am afraid I am giving ammo to the chain drive fans here!!)
I have more to report but need to pick up twins from preschool.

[waterman]

Well this morning I made a few discoveries. I pulled the swingarm, reopened the clutch compartment, and removed the clutch plates. I discovered that if I gently turned the secondary flange (essentially rear wheel), the inner clutch basket would rotate. Turning the flange quickly would overcome the friction that was rotating inner tranny workings. After moving tranny through gears and slowly rotating flange I found that the inner hub would spin roughly 2.5 turns per rotation in 1st and nearly 1 to 1 in 5th gear respectively with progressively less ratios in the subsequent gears. Thus I conclude the transmission gears are not damaged or at least are not causing the trouble I am having.
I am guessing that Gustov has it correct in that I have spun the bevel gear on the input bevel gear shaft where the power is routed. On the 650g model, I believe the output bevel gear is intregal with driven flange shaft and thus could not free spin unless the shaft actually broke.
It is kinda strange that I can feel the normal amount of backlash that is built into the bevel gears (roughly 10 degrees of movement) before the inner clutch hub will move, but when resistance is applied to the clutch hub the flange will continue to rotate without strain until roughly 350 degrees of rotation more. I must have been down to the last bit of spline left on the shaft when I left for work the other day and had to push.
The more I think about this, I wonder if the previous owner hadn't had problems with it and therefore sold (unloaded) it. I will never know but I am a fairly conservative rider, I think I redlined it twice and may have pegged it (85+) once.
One other discovery, the swingarm bearing was rusting on the brake side. If I fix bike will have to look into it replacement. Probably a moot point now...
Would like to encourage others with shaft drive to take a look at these bearings as it is not much more involved to remove swingarm when pulling rear tire. It may even be possible to check and grease bearings without pulling swingarm.
If anyone has any suggestions as to how to proceed, would be willing to entertain them. Has anyone tore into a 650 case and if I do, would I be able to get what parts I need to fix this? Will stop rambling now. Thanks.