HELICOILS

Fortunately the new cork gaskets resumed their proper shape after having been taped to the underside of the cam covers and I bolted the covers back onto the engine with new stainless fittings.

Before I could refit the aircover I had noticed previously that the top bolt hole in one of the carbs had lost its thread. On closer inspection this time I saw that one of the three holes that the elbows bolt down to, on both carbs allready had a shiny helicoil thread insert. I checked the size of the bolt 5/16 UNC and ordered a helicoil kit for that size.

Before I started on this procedure I checked out a few YouTube clips. It was recommended that a drill guide be used to ensure that the drill remained perpendicular to the surface when drilling out the remains of the thread. I cut a substantial block of hardwood and drilled through it with the provided bit on my bench drill.

I first filled all of the holes with paper cloth to prevent swarf entering and I drilled out the thread, but I did need to use a one size smaller bit first as the correct one kept grabbing, I finished off with my wooden drill guide and the correct drill, result nice clean straight hole. I removed the swarf from the hole with small bits of paper cloth soaked in oil.

 

I used the same block to run the thread cutting die through and again cleaned out the swarf with oily paper cloth and screwed the Heilcoil into the newly cut thread with the special tool provided.

As simple as that, elbows bolted down, airfilter fitted and only remains to take the 'AFTER' photo.

AND BEFORE

THATS BETTER