
if i was you i would bite the bullet and drill the thread out. this will not cause you any issue if you want to go back to standard as the standard yam bolt has a locknut on the bottom anyhow

however if the bush wears (with the thread) then there is a possibility it could ride on the thread like a nut and lock up on the top or the bottom of the lever mount

just my thoughts as an engineer

arse.
looks like the bullet will have to be bit.
do you reckon a handrill will be ok as i dont have access to a powerdrill.