Unfortunately, a newer yz250 model engine will not be able to fit the frame of a 1991 model. These engines were designed to specifically fit the frames of certain models of the vehicle and are not universal.
The engine will line up, you might be able to fabricate some engine mounts and make it work. I would check with my Suzuki shop and ask them before attempting such a chore.
it is a 1991 yz250 b1
What why would you want to put an older motor into a newer car? And are you sure this is from a 1991 sounds like a 1992 motor.
1988-1991 yz250 motors are completely interchangeable. Some parts like the cylinder head use the same casting from 1988-1996. Note: although interchangeable the cylinder ports and cylinder head combustion chamber shape differ form year to year. The optimum setup for a 1990 yz250 is a 1991 cylinder with a 1992 head.
It is bolted to the frame and the back of the head. You can put it anywhere as long as it is bolted to the frame and the engine.
the engine will fit, but there may be some modifications in the wiring
the oil drain plug is located near the frame, below the oil tank where the swingarm meets the frame at the bottom of the frame on the right side. There is no engine drain location as the engine is a dry sump system meaning there is no oil stored in the engine other than residual oil.
Frame Up - 1991 is rated/received certificates of: Australia:R Iceland:16 USA:R
If it`s one of the old models 1986 and up to 1991 I am sure it fits directly in the frame, sine I have a 1985 gsxr 750 myself with a tuned up 1100 engine, but it`s a dangerous bike because the frame is not stabil enough with so much power.
Donald M. Frame died in 1991.
Buy a newer one.
No 1991-93 Mustangs use a different frame for the top.