My buddy has an 86 LT250r.He is thinking of having the cylinder ported and polished.But i was told that the 85 and 86 cylinders are junk.does anyone know if newer cylinders will fit on a 86 engine?or if not,do newer engines fit with no frame alterations?

 

No the newer cylinders have a power valve. (87- up) The 85 and 86 didn't, so they can't be swapped. As far as being junk, the ports and the port timing is a bit different, plus there is more after market parts available for the 87 and up cylinders. But if you have enough work done to the motor, it can run with the best of them. After I got my engine work done, I seen no difference with the power valve. But when you produce enough power, you don't really need it anyway.

As far as motor swap, I think people put 87 and up engines in the 85 and 86 frame, not for sure, but I think you can do that. But if your going that far might as well get the 87 and up frame. The suspension on it is better also, so worth the total upgrade.