Gear Shift / Transmission Problem

[BadMonk]

I've been attempting to rebuild a 1981 GS850GLX that sat untouched in a shed since 1983. It's been a project. Last year while the cylinder head and jugs off, I split the cases but didn't mess with the gears. Then put it back together. The bike's in the final stages of repair/replace. Today I installed the rear wheel (for the first time since tearing it down), tried to spin it and it's in gear. So I say to myself "self...I thought it's always been in neutral." Well, okay I grab the shift lever and...ugh what a mess. It doesn't go into neutral. It's stuck in a gear or something. Once in a while the shift lever feels like it clicks...then other times it moves downward beyond what's normal and with a thunk. Then it wants to upshift or downshift endlessly...like it has 8 gears. Other times it won't move at all.

I don't know if the bike was like this when i got it last year, if it's something I did when it was apart, or if something just gave way with age. I'm hoping it's a gearshift problem that can be fixed through the side cover or the oil pan after removing the clutch. I hope it doesn't mean splitting the cases again...yeah right. Dang it. I know my description isn't great but any thoughts on what the problem could be.

 

[tom203]

Pull clutch cover off ,remove clutch,and have a look at shifting mechanism lurking there...

 

[BadMonk]

thanks for the pic, tom203. with the picture, i can see the problem would happen. the thunking sound could be the gear on the shifting shaft hitting the bottom of the case. i'll be able to get to the garage tomorrow with any luck and do a quick look. thanks again.

 

[BadMonk]

Finally...made it to the garage today and, after removing the clutch, found things looking like this:


Also found that the thin washer sitting behind the nut for the sleeve hub was kind of bent up and chewed up in one section.
I'd post a pic but only allowed one per post. Not sure exactly how that would have happened since the bike's not been running or moving.
Anyhow got one off eBay and it's already in the mail.
Hopefully realigning the teeth on the shifting shaft to the cam gear and the new washer will fix the problem.

 

[Carter Turk]

Finally...made it to the garage today and, after removing the clutch, found things looking like this:
View attachment 50642

Also found that the thin washer sitting behind the nut for the sleeve hub was kind of bent up and chewed up in one section.
I'd post a pic but only allowed one per post. Not sure exactly how that would have happened since the bike's not been running or moving.
Anyhow got one off eBay and it's already in the mail.
Hopefully realigning the teeth on the shifting shaft to the cam gear and the new washer will fix the problem.

How does a shift paw fall down like that? Nice call on Tom's part.

 

[BadMonk]

I believe the return spring wasn't in its right place which is the return spring prongs under the stopper arm and a small protrusion (don't know the right word) over the stopper arm. This gives the spring leverage to do its job. Without leverage, it won't have spring and won't return anything.

I don't know for sure how it got that way. Maybe I didn't align things when assembling or things misaligned while jostling the motor to get it together and back into the frame. I don't know. The mystery for me is how the washer got bent and chewed up??

 

[bobgroger]

The washer is bent up after installation to lock the nut in place. Buy a new one, it will be flat. After torquing the big nut fold up the edge to lock. It gets boogered up when someone removes it and tries to use it a second time.

 

[BadMonk]

Okay, thanks for the info on the washer. There's a nice new flat one in the mail headed my way.

 

[KiwiAlfa156]

The gear selector shaft is also held in place by a washer and circlip on the sprocket side of the engine. You might want to check that this is place so the shift quadrant does't get knocked out of mesh again.

 

[BadMonk]

I don't remember a washer and circlip...that mighty explain a thing or two. I don't see them on the parts diagram though. Thank you.

Are you talking about the stopper arm and lock washer maybe?

 

[KiwiAlfa156]

Apologies, I thought you had a GS750E different arrangement on an 850 shafty.

 

[BadMonk]

No need for apologies, KiwiAlfa156. Thanks for looking at my thread and keeping me on my toes...it helps me to be sure about what I'm doing.

 

[TeamDar]

The gear selector shaft is also held in place by a washer and circlip on the sprocket side of the engine. You might want to check that this is place so the shift quadrant does't get knocked out of mesh again.

The 8 valve 750/850 doesn't use the clip. That is why the shaft is longer in the clutch cavity. The clutch cover holds it in place. When installing the cover you must check that the shaft is aligned with the shift cam on the drum.

 

[tom203]

The 8 valve 750/850 doesn't use the clip. That is why the shaft is longer in the clutch cavity. The clutch cover holds it in place. When installing the cover you must check that the shaft is aligned with the shift cam on the drum.

That's what I thought, but was unsure.. so anytime clutch cover is off, things can get knocked off.?

 

[BadMonk]

Is something else wrong?

Is something else wrong?

The gear shifting parts are in and aligned correctly now. The clutch cover is off and the clutch is out. It still doesn't shift and the wheel is still locked up in gear. This is a dumb question but is that normal because it's disassembled? I'm hoping that it needs to be reassembled to run thru the gears...and find neutral.

 

[BadMonk]

So...put it back together and no change. Shifting still feels like a mess.

I verified the teeth on the gearshift shaft were in position with the gears driven by the shifting cam. Then I played around with the cam driven gears and the problem. The gear shifting cam doesn't move. When the dogs on the cam driven gears engage the cam, nothing happens...I can't turn anything. Of course, if I compress the spring loaded dogs on the cam driven gears, it will move until the dogs engage the cam...then nothing.

I'll have to pull the motor and split the cases again. Anyone have an idea why the cam isn't moving? Maybe I reassembled it wrong or something was/is broken...I don't know.

 

[tom203]

I'm wondering if shift drum has been somehow knocked off its correct start position and it's binding up gears. Split cases (ugh) and find neutral by observing gear position, then check orientation of shift drum.

 

[BadMonk]

Thanks, Tom. I agree with the "ugh" since that's sort of what came to mind when I noticed the lack of movement behind the clutch. My thought was a little more colorful than "ugh" but I'll go with that for now. So I at least have a head start because the external gear shift mechanism and clutch are out. LOL! Now, I just have to remove the engine, disassemble the lower end (crankshaft can stay put, lucky me), remove the transmission, and get to the internal gearshift mechanism to check the shifting drum.

That's going to take this old man a while, definitely not a day or two working by myself. I'll post pics when I have 'em.

 

[BadMonk]

Cases split this afternoon, after a lapse of brain power. I haven't looked into the problem yet and won't get to it until tomorrow. I know this - the shifting drum will turn by hand. However, the counter shaft gear set and the drive shaft gear set will not. I honestly don't know if that indicates a problem or it's normal as this is uncharted territory for me. But it seems like that's where the problem is.

 

[BadMonk]

After making double sure that both gear sets were correctly aligned, it seems to be okay now. This afternoon, I got the pistons into the cylinders (and forgot how much of a pain it is to do by myself...ugh!). With some luck, I can work on the gear shift mechanism tomorrow and verify that it's really good to go. So except for stuffing the motor back into the frame (which is also a pain to do solo), the lion's share of the heavy lifting is done.