Transmission issues please help me gs gods!

[jzfn13]

After having done a bit of research i picked up an 81 gs650l as a project a few months back.
This is what she looked like when i got her.

I have since done quite a bit of work and got it running quite nicely.

http://www.facebook.com/photo.php?v=10150710761571113

I just got it pretty much finished except for seat and exhaust, and took it for a test ride. Everything seemed great!!!


Then, I took it around the corner from the shop to a buddys house to show off my hard work. When i got back on it it seemed to only be running on 2 or three cylinders. No big deal, prob a coil. I got her running and rode back to the shop, 1st gear, 2nd gear, 3rd gear, downshift back to second before the turn, POW!!! everything shuts off and the back wheel locks up completely... I crank it back up and try again, 1st, when i shift to second same thing... Now just while it is running it sounds like a box of rocks coming from the case area. I limped it home on 2 cylinders and 1 gear. When i got it back and up on the center stand i can still shift it through all the gears, but neutral is almost impossible to find, and first and second are mega jerky. It still sounds like a garbage disposal in my case. I thought the transmissions were bulletproof? What the heck happened here? How do i fix it? And finally where an i find the parts? Please help me

[Big T]

The transmissions are stout, the rear drive and the helical drive gears are not

Tear down your final drive and drive gears

[tom203]

Obviously disconnect drive shaft from trans to isolate problem. Then run/shift it to see if trans feels like it's crushing rocks. This model has a "direct drive" feature in fifth gear- clutch input shaft is locked to bevel drive gear input by sliding second gear towards the bevel gear- this means the clutch and bevel gears are turning the same rpm in fifth. Hard to visualize, but basically if second gear is messed up, fifth will be a problem also.

[hjfisk]

I have a transmission , and or the helical gears if you decide you need them PM me.

[jzfn13]

Thanks for all the input guys, I cant wait to tear it down and figure this out. Would have never even thought about the final drive being the issue.

[Big T]

Thanks for all the input guys, I cant wait to tear it down and figure this out. Would have never even thought about the final drive being the issue.

That's why we're here

BTDT

[Nessism]

This might be useful...http://members.dslextreme.com/users/...pair_zooks.pdf

[chuck hahn]

On the center stand and in neutral, try spinning the back wheel..feels like a bag of rocks and youll know the obvious end to start at....if it even turns without gorilla forces applied.

[jzfn13]

Got to tearing into it a bit tonight. I pulled the rear wheel. The final drive gears are in perfect shape. The u joint works like brand new, its great. That leaves me at the case. I pulled the four bolts holding the bevel gear in place, but I cannot seem to pop that unit out. Also i found what seems to be an oil drain for the trans, I pulled it off and lo and behold out came what seemed the consistency of motor oil, not gear oil. I cannot for the live of me find a fill plug however. I thought that these transmissions ran off the same oil as the motor, but if so why the seperate drain? Also I rounded the crap off the head of a case bolt trying to find a fill hole, so that should make life interesting... This is what i am talking about.

[jzfn13]

No problems at all spinning the back wheel in neutral.

[TheCafeKid]

Does the motor turn over??
If it were a larger shaftie I'd say you might check the secondary bevel gear box (it drives the shaft) but the 650 didn't have a separate secondary box and was oiled by engine oil afaik. Definitely has a drive and driven bevel gear set though, and it's possible the bearings in those blew up? I've also known of one 650 rider who litterly sheared his drive shaft in two...won't mention any names...

You said it seemed to have dropped a pot or two? My other worry is that unlike the rest of the 8 valve GS motors, the 650 was an insert bearing crank design rather than roller bearings. It's not all that common, but there have been a couple 650s that have eaten their crank bearings. This would at first likely have resulted in a serious jackhammering racket from the engine. I am not a seasoned mech enough to say whether it would have resulted in full lock up, unless of course you also broke a conrod or two. I'd think that would lock things up rather quickly. If that's the case, it's really bad news as the engine would likely cost more in just parts than its worth...

Hopefully it isnt as severe as that though... Fingers crossed for you!

[jzfn13]

The motor still turns over and runs. The motor will sometimes run on 4 cylinders when revved up a little, so i am pretty sure that is just a coil issue there. I can still hear the noise in neutral, as a matter of fact thats where i first noticed it. Before the bike really acted up, I thought maybe it was just slipping out of neutral a bit with a sticky clutch to boot. I am going to leave for Las Vegas for a week on Wednesday. Hopefully that will help me clear my mind a bit. I will try to get a video up as soon as i get back. Maybe that will help you guys gain some insight.

[tom203]

The motor oil likely gets to bevel gears by having no seal on output from trans (I've never investigated and don't plan to). The drain lets you get the gunk out of the cavity- otherwise it would just build up. Sounds like rear wheel and bevel gears are OK (spins nice in neutral), so unfortunately that leaves the tranny.

[jzfn13]

That pic is super helpful, and super scary all at the same time. I am pretty sure i can take it apart, but it looks pretty tough to get back together lol. I think i can at least understand what is going on in there and what is and isnt meshing there now. Starting to make more sense. Now whether to tear it down or just find another whole motor assembly with unknown problems...

[tom203]

I doubt you'll find new parts, so used stuff, with some stripper ripping them out is more likely- no thanks! Probably safer to get another unit (whole bike) and transfer your work there. Most of these bikes seem to get sidelined by poor carb and/or charging woes and not by tranny problems ( I'm counting on this with my 38k bike). Then just sell off the surplus stuff. I've seen motor assemblies on ebay, but unless the guy was in your area, shipping is prohibitive.