R80 or R100?

[KARSTEN]

I have just purchased a 1985(10/84) RT from a used bike shop.It was sold to me as an R80RT,having owned a "83 R80RT some years ago,I do not recall the jugs to be that big.Could it be a R100RT?The bike is not in original paint and has no designation on the side cover.He did not have the title on hand(bike was on consignment in his shop)Wonder if the vin# will tell ?

[jforgo]

VIN will tell - at least how it began life.
To my eyes, the mono's appear to have relatively wider jugs, due to the rest of the styling. But the 100 is an overbored 80, so would externally would look similar.
There were no, at least US, 100's for 1985.

[Rich]

I do not recall the jugs to be that big.


I've experienced those same thoughts. :lol

Ok, serious mode now, I bought a R80RT in 1986 and like jforgo mentioned, the 100's were not available at that time. I had been riding a Goldwing for a few years and was saving my pennies to buy a R100RT. And when the time came that I could actually make the deal, no R100's. I was disappointed at the time, but that R80RT was the neatest little bike I ever owned. I wish I had never sold it. Best of luck with yours, you will like it.

[Acejones]

I know the bike you are talking about. It's white and you bought it from a shop in Foley. From what I understand there is a 1000ccjug kit that is sold by a British company and that is what that bike has on it. I think once you get the vin number, you will also find that it may not be a real RT.

[26667]

Don't the R100's have black rocker covers, while the 80's have the same color as the rest of the motor?
Just saw the above post after I wrote.

[20774]

Check VINs in a number of places:

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

http://www.bmw-z1.com/VIN/VINdecode-e.cgi

[97077]

Look on the the cylinder where it connects to the engine block. You should see the number 10 or 80 that will tell you the size unless some one changed heads. Either way you will have a great motorcycle. love those airheads. :brow Kevin

[KARSTEN]

thanks for the quick info,checked the vin and it is a R80,the # stamped on the cylinder close to the block is 10,so I guess it is a "big R80".No doubt I will like the bike.Have liked all previous airheads,K bikes and that one oilhead.(Once all issues will be sorted out and it has ISSUES galore),thanks again, Karsten

[bikerfish1100]

Don't the R100's have black rocker covers, while the 80's have the same color as the rest of the motor?
Just saw the above post after I wrote.

valve covers all fit the same, totally interchangeable between engines.

[97077]

Hi Karsten
As I understand the number on the cylinder, the 80 was for 800cc and the 10 was for 1000cc. I never herd the term "Big R80". Could someone explain the term "Big R80" :brow Kevin

[fracture]

What about final drive ratio? I seem to remember that there was a difference between 800cc and 1000cc final drive ratios. Final drives can be swapped so this item may not be original either.