Help me and my 82 R80RT

Hello all. New to membership, but I've been all over the forum. In fact I've been googling for four days straight and can't come up with anything that exactly explains my symptoms.

Bought the bike exactly a month ago, only running on one cylinder, and completely bastardized by spray paint by the seller. Got a good deal at least.

A carb cleaning and float adjustment got me running full strength again. I then had probably the greatest four weeks of my life riding this old gal.

Until a few nights ago. It happened after about an hour of moderately spirited city driving with a friend on the back. No bangs, crangs, snaps or pops, it just started to slip while I was in gear. Anything over 1/4 throttle, and I was slipping and making a godawful rattling/chattering noise. I very gently, and just barely got it home. I live up quite a steep hill and had to kick my feet in first gear to get up.

My most optimistic thought was maybe the clutch got a bit hot. However it didn't magically fix itself when I went for a test ride the next day.

What's this sound like, gurus? Little bit of friction somewhere, enough to move me along slowly, but slipping and making a hell of a racket with anything over 1/4 throttle. Sounds like it's coming from directly beneath me, maybe a bit on the right side, right around the u-joint maybe?

Any input is greatly appreciated before I tear into it. I'm a decent wrench, but I think getting into the gearbox is over my head.

Btw bike has 39k miles. I changed all the fluids when I got it, but let's assume PO probably neglected some maintenance. Definitely had chocolate milk in the gearbox when it came to me.

Thanks again in advance

That sounds exactly like a stripped spline - probably the clutch hub and transmission input shaft. Ouch!

Welcome to the forum! Sorry that your 4-weeks has turned sour.

I'd start with some easy stuff first.

- clutch cable adjustment -- https://forums.bmwmoa.org/showthread.php?39773-No-adjustment-left-in-Clutch-rod&p=499945#post499945
- transmission in neutral, see how the rear wheel turns. Put it into various gears...probably have the spark plugs pulled. How difficult does it get...should be relatively easily to rotate the rear wheel.
- be sure the valve clearances are set right, but don't think that's part of the issue. Valves can close up on the '81-84 models but not typically at those low miles and less so on the 800cc bikes

Given the chocolate milk fluid in the gearbox is a clear indication of water in the oil. Probably slipped in at the boot on the speedometer cable where it goes into the top right rear part of the engine. Suspect you'll need to replace the boot. If the water was in there for any length of time, could very well have rusted the bearings which have not eaten themselves while you've been riding. A little late, but something to have tried would have been to drain the old gear oil, replace with new, ride for a little bit, maybe even only 25-50 miles and then drain again. Repeat until the fluid comes out clean. Likely wouldn't have save it though.

Try the easy stuff but begin to focus on the health of the transmission.

Paul suggested the transmission input spline...sounds like the transmission is coming out anyway and a good time to check all that.

Thanks a heap y'all. Stripped splines on some shaft somewhere did seem the most likely thing based on my googling. Also one of the more expensive solutions, right? The clutch cable was moderately out of adjustment, but obviously fixing that didn't fix my issue. In hindsight I would've ridden a little slower if I thought it would've given me 6 weeks of fun.

I'll begin pulling the gearbox tonight. Sounds like it's going to need to be opened up though. And as I understand it, that seems to be best left to the professionals? I mean, I'm sure I could dismantle it, but getting everything back together is the important bit.

Depends on your level of skill. Personally, I'd give it 4 wrenches out of 5 to open a box and fix the insides. Sometimes it's worth it to have a professional go over the critical parts. The link in my signature line has a section about transmissions...there is a page or two which goes through the process. The key is to get everything shimmed just right.

Where are you located...helpful to have that in your profile? Maybe you're near an Airhead guru who could work on it if you simply brought the transmission to them.

Right, it's the shimming and alignment that makes me nervous. Updated my info: I'm in central Arkansas. I've got an oldtimer nearby who specializes in "old" bikes, not necessarily airheads. I think Triumph's are his bread and butter.

I know there's a registry of members by location somewhere. Is there a list of recommended shops somewhere on the site?

Also I've been through some of your articles, but after a week straight on snowbum's site I think I need a little break from technical reading lol.

Check my signature line for a list of independent shops...the URL I use is the micapeak one. Vech at Bench Mark Works is near you but he might not work on these models. Good places on the east and west coasts.

Absolutely beautiful. Thank you for spoon feeding me lol. New guys amiright? Hopefully I'll be back on two wheels soon. Thanks so much boss. I'll report back with my findings. Cheers and happy motoring.

So, you pulled the transmission? Did you drain the fluid out? Any chunks, debris, or pieces on the magnetic plug? What have you found? A good question to ask folks or research is where to send it off to. Several good folks that really do good work. Wonder how much an overhaul might run??? ….……….Dont eliminate the clutch being the culprit which is a good thing as far as money goes...…...God bless......Dennis

I'm with Paul on this. Based on the chattering. Could also be the spring loaded cushion on the input shaft with a broken ear based on carrying a rider; but that's a long shot.