I’m forever having to tighten up the bolt holding the side-stand on my Monster 750ie onto the engine case. I’m reluctant to use lots of force in case I strip the threads so wondered if I should use some thread-lock on the bolt to stop it working loose. Is this a good idea and, if it is, what type should I use?
it's a really good idea, but choice of Loctite Will be controversial. If you type "medium" Loctite into Google you will come up with several options that are all acceptable. Bear in mind that you need to clean both screw and crankcase threads thoroughly for the Loctite to work as intended.
Loctite 243 - oil proof, medium-strength (i.e. you can undo it easily but will do the job). As Chris says - clean & degrease both threads thoroughly. No change in stated torque needed if using Loctite.