Motorized Bicycle Engine Mounting
Make sure that before you try any type of loctite, super glue, or other magic bolt fastening system, make sure that all your mounts sit flush, that there's no gaps, no play, no nothing. you can easily grind down a stock mount with a dremel or a grinding bit and a drill to match the fit to your frame, just don't get to crazy.
basically, what i'm saying, is no bolt is gonna hold up to the torque of your motor if it's not mounted right in the first place.
the only thing i use loctite on is the set screw on the clutch flower nut, and that's as a preventative action, i never had one loosen up.
i actually use anti-seize compound on every external bolt on my engine (after upgrading all the hardware, to prevent stripping, seizing, binding, whatever. i like my bolts to come out when i want them to.
i've never had a problem with bolts loosening up. my pre-ride check involves looking at bolts to see if they appear loose. every few weeks i put an allen wrench on them and see if they turn. if they don't, i don't force them. and i'll maybe get a fraction of a turn on one now and then.
if you keep forcing them every day, they'll strip, flex, break, etc.
if you tighten it right the first time, it'll stay tight.