A forum for owners of Yamaha TTR250 trail and enduro bikes!

I had a couple of clutch covers that I had put to the back of the shelves as I couldn't figure how to repair it and the covers are too valuable to throw away.

The challenge is to drill the thread out for the Helicoil insert absolutely at 90 degrees.

This is the kit I used - not actually Helicoil but a copy:

I enlisted the help of my brother to gain a few extra brain cells and we came up with a plan.

We removed the pressure relief valve and blanking plugs on the inside of the case to give a vertical face to which we screwed a squared off piece of wood to give us the right angle we needed.

It was then possible to position the workpiece in the drill stand to drill the hole. Worked perfectly - phew!

Using the block of wood to position the clutch cover in the vice it was then an easy job to tap the hole and insert the Helicoil.

I made sure all the swarf was meticulously cleaned out of the holes and then put back the pressure relief valve and oilway blanking bolts.

Worked a treat!

Hope that may help someone now or in the future

Brian

PS Sorry not to have taken more photos but we were really concentrating to get it right! Hope the explanation makes sense.