Time-sert ok here?

[stopintime]

While replacing my starter I discovered three-four stripped threads in engine case bolt holes - for the side cover.

I was warned that Time-sert might not be the thing because there is too little metal to work on/in (drill and cut new threads). As far as I can see, the walls are about 4mm thick.

Enough? Too little? Go Helicoil?

[ducpainter]

According to Google time-serts have a 1 mm wall thickness, but the collar, or flange, is larger. If you can verify the flange is smaller than the metal you have to work with I see no issue using one.

I've had good luck over the years with helicoils installed using loctite.

[koko64]

I use helicoils for the M6 bolts securing the outer cover. The torque value is low.

[thelonious]

Side covers often use a variety of different screws lengths. Trouble is people take them all out together and mix them up, then use screws that are too short in some holes and over tighten them which leads to the threads getting stripped. If you are lucky, only part of the threads will have been damaged and there may be good threads below that will work with a longer screw and the correct torque. You may need to clean them up with a blind hole tap first.

If not - these stripped holes are meant to take M6 screws, yes?

Another option would be to drill out the holes with a 6mm bit, which will only remove the damaged threads and not the surrounding metal. Luckily, 6mm is the correct hole size for an M7 tap - so you can now tap the holes to M7 size and use M7 screws instead of M6.

I think that will remove the minimum amount of material and will be a stronger and simpler solution than using inserts.

Your only issue might be finding a M7 blind hole tap and M7 screws as it is not a common size.