can anyone tell me if the motor out of a 06 500 foreman fit into
a 99 400 foreman fm.

bouth a 400 forman. wrks excellent but found the bittom
of the motor all done in jb weld. leakin oil

 

Doubtful, the 450 frame looks very similar to the 400, but the 500 frame is different, I would guess that the 500 will be taller. Even though early and late 450s are almost identical, you can't swap engines without modifications as the shaft that goes right through the engine is a different length on permanent 4WD to that on switchable 4WD. The 06 500 had a faulty gearbox anyway, unless it has had a rebuild with later type gears.