The needle valve mount on my.46 FX backplate is broken off. Will a .46 AX backplate fit? I'll install a Tower.46 rear needle valve assembly which has its own mounting bracket. A far less costly repair.

Thanks,

Roy Perry

You will need to install a .46FX rear cover. The AX parts don't have the same bolt spacing, and the diameter of the inside of the crankcase is different between the engines.