Helicoil kit for timing case bolts

[Gstovold]

Hi all,

My bike is an AJS M20. One of the holes for the bolts holding the timing cover is stripped. I am struggling to find a kit that is correct. It looks as if the bolts are 5/32" diameter. I am not sure of the threads either 28TPI seems probably right but not sure.

Does anyone know definitely what these bolt are and how they are described BSW? or BSF? I might then have more luck in finding a kit.

Thanks.

Geoff

[Groily]

They should be 2BA. (British Association)
Inserts / helicoils are available from various sources. Google will be your friend. Bodges are a bit tricky on these particular fasteners, so the right kit is pretty well essential.
It's a good plan to use the correct cheesehead screws when you put it back together, as people tend to over-tighten using allen-head screws. And then . . . guess what?
For more data, see eg http://www.ring-plug-thread-gages.com/P ... -data.html
To get new screws, kits are available from Club Spares, nice deep-head domed-top jobbies.

[56G80S]

From experience, it's important to use the drill (hopefully supplied) and tap in the kit and not to think that you know better. It is also really important to make sure that the drill enters the casting perfectly square. For me it was also important to take the insert into the castng sufficiently that the top (or outer) part of the insert goes below the surface of the casting. This makes sure that the insert doesn't unwind when the bolt / screw is undone.

I used V-coil to do this for the rocker box bolts.

Apologies if you already know all this.

Johnny B

[Gstovold]

Thank you Gents. That is very useful. I should be OK now.

Cheers

Geoff