Cam cap Thread has gone in Cylinder Head GS850GL What Tap size Recommended

[Guest]

Guys Im just about to finish the top end rebuild of my 1982 GS850GL had the last Cam cap bolt I've gone to Toque up is just spinning looking inside it looks like the thread has gone !!!! Gutted
Im probably going to have to re tap it what size drill bit and tap size and Bolt should i use ???
Or should i helicoil with m6 1mm ??
The 0910306026 Bolt(6x39)
Any help would be greatly appreciated as always
Sorry about the poor picture but i know you guys love em
So Near yet so far

[blowerbike]

many of times when in a pinch i use a 1/4-20 bolt in it's place.
no drilling....the bolt will self tap if careful.
not the expert way but this has save my azz many times.
small heli-coils are a pain in the azz especially when the head is on the engine/bike.

[chrisfev]

Thanks Blowerbike will give it a try

[chrisfev]

Big Thanks blowerbike that worked a treat

Onwards and upwards !!