Ive got a ty250 mono and it is leaking gearbox oil threw the clutch cover, I have replaced the gasket but the thread in the crank case for one of the lower clutch cover blolts is stripped, is there anything I could do to fix this?

Cheers Lewis

Hi Lewis.

What you need is a 'helicoil'. You'll also need the appropriate helicoil tap and helicoil insertion tool.

I'm assuming you don't know what one is. If you do, then sorry.

A helicoil looks very much like a compression spring only it is threaded to accept the original screw.

The stripped hole is tapped out (larger) with the helicoil tap; the helicoil insert is then placed in the tool, which then inserts it into the newly tapped hole. Once in place, you wind the tool backward to snap-off the insertion tag and then continue to wind the tool come all the way back out. Job done.

To be honest, unless you have lots of stripped threads - or intend stripping more! - it may be cheaper to find a local engineering firm to do it for you. It'll take them all of 10minutes to do.

Thanks for your info, I wasn't sure if there would be enough room for the helicoil on the crank case as its quite thin, so I will see if some were local can do it.

Cheers

There IS another, more complicated way but I don't think it will be strong enough.

Used metal putty to fill the hole completely; place the casing back on and use a drill (same size as the clearance hole in the case)

to 'spot' the center again. The drill out with tapping drill (5.2mm if M6 thread) and re-tap the hole.

It might work but I don't hold much hope in in being strong.