Stripped Thread - Best Solution?

[Ray White]

In this case I would think 9mm of good thread should be fine with the longer bolt. I would leave it but add a little thread locker.

Ray.

[Howard Wright]

Hi

I’d be cautious about using too strong a thread lock for these bolts.  Unless you’ve transferred the timing marks to the front cam pulley you need to have the starter housing off every time you set the timing. I had some dynamo problems with my RK and the housing was on and off like a yo-yo  . 

Cheers

Howard

PS On the three early engines I’ve worked on all had these holes drilled and tapped to 3/8”.

[Ian McGowan]

John, I would use longer bolt for now and save helicoil for next time you have the engine out - much easier to do when you can get right over the top of the hole.
   Check the actual thread first though; there has been mention here of BSF but, one of my crankcases has 5/16" BSW at this point.
I definitely would NOT use thread lock on these bolts.