1980 R100t motor and trans into a 1984 R80 RT

[newbedoo]

I want to place my R100T motor and trans into a 1984 R80RT with a RS fairing.
Are the parts interchangeable, will I have any major problems or fabricating to do this project?
brymac@shaw.ca

 

[darryl cainey]

Yes that should be no problem.

 

[beemerphile]

No issue with the engine/trans swap, but I would hate to trade a 1984 trans for a 1980 trans. If the 84 trans is in good shape, I would mate it to the 80 motor and call it good. You would have to re-use the 1984 clutch, throwout ass'y, and flywheel to make the swap of the newer trans to the older motor. Even if I had to rebuild the 84 trans or refresh the clutch, I still think I would do it that way for the better shifting and easier clutch pull.

 

[dennisdarrow]

Some of us like the heavy flywheel and clunky shifting.........Make the change and see if you like it. For me, you are gonna have quite the hot rod with the R80 "short" rear end gear differential.......It will make its revs and power lower and ohhhh so strrrrong.......have fun....Dennis

 

[beemerphile]

Some of us like the heavy flywheel and clunky shifting.........Make the change and see if you like it. For me, you are gonna have quite the hot rod with the R80 "short" rear end gear differential.......It will make its revs and power lower and ohhhh so strrrrong.......have fun....Dennis

That is why it seems especially appropriate to me to lose the flywheel effect. It isn't as needed with the lower gearing and the bike will spin up faster with the "clutch carrier". Also, as we (I) become more and more feeble seniors, the lighter clutch pull becomes significantly more important. I guess they all have that satisfying "clunk", but the later ones seem to me to have less false neutrals and such. A 1984 trans would be after the shift cam improvements and troublesome shock couplings, but before the accountants ran away with all the circlips. I think it is pretty Ideal. If it had 80+K miles or better on it, I would have one of the airhead aces give it a good going-over.

Either box will work so long as everything after the crankshaft nub is appropriate for the chosen box.

 

[lkchris]

The new trans doesn't mate to the old engine.

 

[20774]

The new trans doesn't mate to the old engine.

Sounds like the OP is moving engine and trans together:

I want to place my R100T motor and trans into a 1984 R80RT

 

[stevenrankin]

What about the wiring harness difference between 1980 and 84? Didn't the 80 have points in a can? The 84 has the electronic hall effect and ignition module. St.