Installing Flywheel

[Yamahauler]

I had the flywheel off on my YTM, now I've replaced the cam chain and I tried putting the flywheel back on, It butts up against the idler gear but I can pull it back off with my bare hands, Is this normal? Does it eventually seat or something?
I was thinking it might be that woodriff key. I read in other threads it can get sheared, but mine looks fine.

[TeamGeek6]

If its a tapered shaft, itll come off by hand until its bolted down, then the roughness on the 2 surfaces lock together. I gave up on using a key, it doesnt do anything unless the crank locks up then it prevents it from twisting.