yamaha rx1
Amsnow
Biker heritage
Yamaha built its Genesis Extreme sled engine on the R1 motorcycle program. You'll find the inner workings to be directly peeled off the bike, while the external castings are designed to fit it into the sled chassis. The camshafts and cam timing come from the '01 cycle as do the intake valves.
The exhaust valves are derived from the '02 bike, but use a higher nickel content material to cut 2 grams each. The timing scheme goes like this: triple 23mm intake opens at 31° BTDC, closes at 57° ABDC; dual 24.5mm exhaust opens at 60° BBDC, closes at 36° ATDC.
The cylinders are very over square, short strokers, measuring 74mm across with a 54mm stroke. The pistons come right off of the '02 bike engine. The combustion chamber is also straight from the R1, with a compression of 11.8:1.
The dry sump oil system uses the same spin-off filter can as the R1 and FZ1, so they will be readily available when the time comes.
Yamaha is touting the RX-1 engine as incredibly durable. It is recommended to change the oil after the initial break in period is wrapped up, about 500 miles. After that, do a change once a season or 2,000 miles. At about 25,000 miles of service, Yamaha recommends a valve train inspection. That's rugged!
The crankshaft is a new piece, made specifically for the RX-1. The PTO shaft is connected to the primary clutch via a rubber-isolated gear reduction system. This reduces the engine RPM by a 37:31 ratio to help keep the clutches safe.