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ketama
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Sierra Foothills
Joined: 01/19/2018
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A friend want to sell his 1984 R80ST but thinks I might not like it because I am a taller rider. He said the seat pushes him towards the tank and his shins hit the cylinders.
I had an '83 R80RT years ago and kind of remember feeling like I would like to push back a little on the seat but it wasn't too bad.

We are wondering if the 1980s R80s all have the same frame geometry, foot peg locations, etc.?

If so, I thought I could get a seat made that improved the ride somehow and made it more comfortable to ride the ST.

I know the newer GS models are supposed to work well for taller riders but I like the retro style BMWs and plan to do more local than long range riding.

Any thoughts?

schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
Posts: 6423
Welcome! How tall are you?

Welcome! How tall are you? I think you're going to find most post 1969 bikes to have about the same geometry...the G/S or GS models I think only differ in terms of how high the seat is off the ground...but the distance to the footpegs will more or less be the same...within reason.

Click on the various models on this page to look at seat heights...that might be a place to start.

http://www.bmbikes.co.uk/bmwmodels.htm

If you really want to go a bit radical, you could put on a set or rear-sets which move the footpegs back, but it promotes a forward lean position.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

ketama
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Sierra Foothills
Joined: 01/19/2018
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1984 R80 ST

Thanks for the link above. Yes, it looks like the 1983 era RT, G/S, and ST wheelbase, ground clearances, and ride heights are all about the same. Any differences could be attributed to front fork head angles, wheel sizes, and suspension/spring differences.

My friend bought the bike from a dealer who took it in after the previous owner dropped/crashed it. He had to redrill the rear fender mounting holes because the fender was offset from the tire. Sounds like the guy bent the rear frame. If the tabs where it attaches to the front frame are not bent I was thinking it might be worth replacing the rear frame section...or, just bend it back somehow.

I am 6'4" but I think it might work if I changed the handlebar angle a bit and got a seat that would allow me to sit back a little further.

khittner
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VBMWMO #8223
Joined: 02/15/2012
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I don't know the respective

I don't know the respective measurements of the bikes, but the early-to-mid-eighties monoshock bikes (R80G/S and R80ST) used a different frame than the twin-shock R80RT. I've always heard the monoshock bikes referred to as "small-frame" bikes, and the twin-shock bikes as "large-frame" bikes. I believe the monoshock bikes/frames had more in common with the R45 and R65, than with the /7 series R60/R80/R100. The 800cc engines were used in both frame types, but that's were a lot of commonality ended; seats, tanks, etc. do not exchange well between the two frame types. What any of this means for how a bike/frame accommodates riders of particular dimensions, I'll leave to others with comparative experiences of both.

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Konrad

ketama
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Sierra Foothills
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Airhead handlebars for taller rider

Thanks for the replies. I went with a low mileage '84 R100T for the larger frame. I need to mess with the handlebars though because this one is set up with the TT bars and half fairing that puts all the wind in my face.

Any suggestions about handlebars? Stock RT bars are still available for $150. Not sure what bars would have been stock with a model "T" so not sure it could accommodate an RT or taller bar without lengthening cables, etc.

schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
Posts: 6423
You can begin to ask about

You can begin to ask about how much pull-back each set of bars has and then gaging how that might work for you. Also, you could consider a set of bar-backs...this is similar if not the same as I have on my /7.

https://www.ebay.com/itm/BMW-Motorcycle-Handlebar-BAR-BACKS-CLASSIC-MODE...

I sit behind a Lufty fairing but still like to be sitting more upright...suits my style or riding. Whether you'll need new cables...my guess is you would. What you don't want are cables to the carbs that take a sharp bend right at the carb. That affects synching and operation.

As for the '84, be aware that BMW messed up with the seats in the '81-84 era. The seats don't transfer heat well, resulting in more heat retention in the valves. It's worse in the 1000c engines, and worse still in full-faired bikes. You'll need to monitor the valve clearances and when they start to close up every say 500 miles, time to get the whole top end done.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

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