retarget animations make my biped character small and deformed

So I’ve been trying to retarget the animations from the starter pack onto my character which was rigged in max with a biped, and he laods in fine, but when i retarget an animation, he goes x100 smaller and screws up in a ball?!
Ive re linked all the bones to the humanoid rig and my own animations work fine, I just cant seem to get the retargeting to work, anyone else had this problem? Scale shouldnt be a problem as hes the exact size of the blue man in-game.
Heres a pic of what it looks like playing the animation

any help would be greatly appriciated!