‘83 r80rt

franz · Feb 13, 2019

Thinking of purchasing this bike. This will be my first airhead. I’m a good wrench but have never worked on one of these. Thinking of everything I need to do to get it where I want it. Carb rebuild $500, Suspension replacement/rebuild, $700 in parts, brakelines, tuneup, better ignition. It all adds up. Should I be considering an unleaded conversion on the heads? What else do I need to be think8ng about?

As far as condition, the owner claims it was always stored inside and has 30K miles. He said it was always serviced at BMW dealerships. He is not a mechanic and didn’t do it himself. I think it’s a great bike but need some advice on what I’m getting myself into. Thanks.

20774 · Feb 14, 2019

Frank -

The 800cc bikes were know to be the smoothest. Certainly, getting to all the basics would be a good idea. Why do you feel it needs a better ignition? The electronic ignition that came with the '81-on bikes works pretty well. Some consider improving the charging system to get higher output for other electrical needs.

As for the unleaded conversion, it's something that should be done at some point. But with 30K miles, the bike is just beyond break in. The 800cc bikes produced less heat which made things slightly better. But this situation is something you can monitor. Set the valve clearances and monitor them at say 500-1000 mile intervals. When the clearances begin to close up quickly, then it's time.

Do the basics and get to know the bike, then start to attack the things that need attention.

PAS · Feb 14, 2019

Frank,
Dont start throwing money at it unless it's necessary! The amounts your quoting are very high and I find that not to be the case. Sounds like a nice bike that will give you years of service.

stevenrankin · Feb 14, 2019

R80rt

I fully agree with Kurt and PAS.

From my own experience with a 84 R80RT, I upgraded the charging system to a higher ouput unit. I ONLY did this because I am runing with electricly heated hand grips, an electric jacket and extra lights. Without all of the extra load on the charging system, the upgrade would not have been needed.

I used the Omega system from
http://www.motoelekt.com

Enjoy the bike as it is for now. Worry about any problems with valve reccesion when it shows it's ugly head not before. Put the money into the gas tank and worry about that cost later maybe at 60 or 70K if it happens. LOL. St.

franz · Feb 14, 2019

Guys,

Thanks for the advice. I figured I was probably getting ahead of myself. Regarding the ignition, I just wasn't sure if this bike is in the era of those that need an ignition upgrade to run better. I will need to upgrade electrical output as I too run with heated gear when the weather turns cold. Not sure if I'd ever hang aux lighting, I don't want to change the bike appearance. I wanna keep this one period correct as much as I can. I just hope I can tolerate the seat.

http://marketplace.bmwmoa.org/classified/1983-r80rt-listing-15434.aspx

PAS · Feb 14, 2019

My 81 R100RT still has the original ignition except for the updated diode board and high output voltage regulator. 174K

stevenrankin · Feb 14, 2019

Seat

If you decide to upgrade the seat, stay away from Corbin seats. They have by far the worst customer service I have ever had the displeasure of dealing with.

I bought a seat for my RT from them, had problems with comfort, was told to send it back, paid to send it back. They had the seat for two months, NEVER contacted me with any questions regarding my complaint. Sent the seat back to me WITHOUT DOING ANYTHING to it. I was then told in follow up conversations, I could PAY extra to have my problem solved.

I hear nothing from Corbin during this time. No questions as to why I sent the seat back. I had enclosed a note and had email'd customer service before hand. Now, I am supposed to pay to ship it back, and pay another couple of hundred bucks on top of the money I have spent. St.

franz · Feb 14, 2019

Although I've had them before, I would never put a Corbin seat on this bike. I think it would change the appearance too much. If anything I would re-upholster the original while keeping the same form.

Sorry for your drama with Corbin. I never had bad customer service from Corbin but then again, I was buying for HD, which seems to their bread and butter. For that matter, I've never put a Corbin on any of my BMW's. I have both a Sargent and RDL for the GS and those work best for me.

Thanks again for all the advice. If I buy it before it gets away from me, I'll leave well enough alone. Tune it, adjust the valves, balance the carbs, bleed the brakes, shine it up, and ride it.

khittner · Feb 14, 2019

You won't need heated gear beyond an electric vest if you leave the RT fairing on the bike. I've ridden my RT into the mid-30s and rain with just a Widder electric vest under my Darien, and a pair of deerskin gloves. In Alabama, you'll be able to ride year-round; the off-season for an RT down there will be in the summer. If you can't determine from the PO the last time the transmission input splines were lubricated, include that procedure as part of your baseline servicing of your new ride. The 800s are great bikes; enjoy.

PAS · Feb 15, 2019

I thought you already bought it! Putting it out there for all to see may have not been a good idea.

franz · Feb 15, 2019

I don’t care. It’s good advertising for the seller. If it goes before I get a chance to buy it, then so be it. It does seem like a good bike though.

vark · Oct 15, 2019

franz said:
I don’t care. It’s good advertising for the seller. If it goes before I get a chance to buy it, then so be it. It does seem like a good bike though.

Did you end up purchasing this R80? I am considering this model and would be curious to hear your impressions. Thanks.

franz · Oct 15, 2019

vark said:
Did you end up purchasing this R80? I am considering this model and would be curious to hear your impressions. Thanks.

I did buy the bike and I really like it. The rear shock is worn out though so I need to replace that. Bike runs a little rough as well. I am rebuilding the carbs this winter. Plugs and valve adjustment are done so I've ruled that out as the cause.

vark · Oct 15, 2019

franz said:
I did buy the bike and I really like it. The rear shock is worn out though so I need to replace that. Bike runs a little rough as well. I am rebuilding the carbs this winter. Plugs and valve adjustment are done so I've ruled that out as the cause.

Did you actually buy the 1983 model that was the subject of this thread, or a later monoshock model? You mention the “rear shock”, but I was under the impression the 1983 model has “shockS”.

franz · Oct 15, 2019

vark said:
Did you actually buy the 1983 model that was the subject of this thread, or a later monoshock model? You mention the “rear shock”, but I was under the impression the 1983 model has “shockS”.

You're right, I didn't buy that bike. I bought a '94 Euro Spec R80RT monoshock. 20K miles. Really nice condition. Thanks for catching that.

vark · Oct 15, 2019

franz said:
You're right, I didn't buy that bike. I bought a '94 Euro Spec R80RT monoshock. 20K miles. Really nice condition. Thanks for catching that.

Ahhh, gotcha. That sounds like a really neat one you found. Congrats to you.

Was there anything about that ‘83 that caused you to steer away from it and toward the newer monoshock version? I’m new to airheads and just looking for datapoints to help focus my search. Thanks again for your replies.

chunk · Oct 15, 2019

franz said:
I did buy the bike and I really like it. The rear shock is worn out though so I need to replace that. Bike runs a little rough as well. I am rebuilding the carbs this winter. Plugs and valve adjustment are done so I've ruled that out as the cause.

Also, don't overlook a proper balance of the carburetors as a cause of rough running. These bikes are very sensitive to poorly synced carbs. Good luck.

vark · Oct 16, 2019

chunk said:
Also, don't overlook a proper balance of the carburetors as a cause of rough running. These bikes are very sensitive to poorly synced carbs. Good luck.

Briefly, what does balancing carbs entail? Is this a DIY service item, or best left to the pros? Is this a common problem with the R80 airhead?

20774 · Oct 16, 2019

It's not a "problem" or "bug" but rather is a "feature". The carbs on any Airhead need to be working together to get the smoothest and best performance out of the engine.

Snowbum has very detailed coverage on this here:

https://bmwmotorcycletech.info/synchcarbs.htm

Basically it involves a number of steps:

- get the right mixture for each carb, slightly rich
- get the right idle speed
- iterate back and forth on the above a few times
- get the best tension on the throttle cable

All the above is done after a 20 minute ride on the bike to warm things up. Have a couple of fans to blow against the engine while running to complete each step.

vark · Oct 16, 2019

Thanks very much for that carb info and link. Very helpful.

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