Thank you
ok the pistons first off the 85-86 motors are 1/2 breed motors they are 1/2 piston port 1/2 reed motor & were not the best setup IMO avoid them if you can ! & they have a bigger bore with a shorter stroke ok the 87 motor was a spin off of the 86 rm 250 engine with the larger intake reed cage but the lt had a bridged exhaust port & you can use the 86 rm 250 piston in the 87lt's & it doesnt need the piston pin thrust washers big + but it is only a single ring piston now the 88-92 pistons had a cut away on the intake side to keep form blocking the flow of the intake to the cases the 88-92 pistons can be used in the 87 to improve flow or you can machine the cutaway in the rm piston for the best of both worlds IMO |