D3MON
Hardcore RCTalk User
setting gear mesh is kind of a learned art. it will take a few tries (at least it does for me) to get it how i want it. you want just a little bit of slop enough where you can feel the gear rocks just a tad to where you can feel it but can hardly see it.the bell gear is the gears mounted directly to the engine. the 3 mounted to the transmission are the spur gears.
for setting the mesh with paper you slide a piece of paper between the bell gears and the spur gears then hold the engine squarely against the spur gears semi tight. dont need to squeeze it.
to check spin the clutchbell and make sure that gears spin freely. also rock the clutchbell back and forth to make sure there is not too much slop!
the threads in the crank are super hardened typically and should be find. try threading a new bolt in to make sure that there is no binding or anything with the threads.
while rocking the bell gears make sure to hold the spurs solid so it doesn't rotate.