Rocker cover thread size

[David Simmons]

I’m quite happy today, as I’ve managed to start my bike and go for a ride. This is following a top end rebuild to try to restore compression, which turned out to be unnecessary as the problem was a slipping clutch which meant it slipped before pushing the engine over as it was unable to overcome the compression. All fixed now.

Point of the post.
As part of the rebuild several of the rocker box studs were discovered to have stripped threads.
What size are these bolts as I’m planning to Helicoil the holes, rather than going up a size to metric which I have all the gear for. I need to make sure I order the right size helicoil kit as I can’t afford to order several.

[Red Gauntlet]

5/16" BSF all of them.

[SPRIDDLER]

As part of the rebuild several of the rocker box studs were discovered to have stripped threads.

Tip:

Clean out the blind threaded holes. People try (unsuccessfully) to cure a not uncommon weep from the r/box to head joint by increasingly tightening the bolts (until they strip the thread in an alloy head), but the gasket doesn't compress any more as the bolts have bottomed out on crud (e.g. old gasket debris) that's compressed at the bottom of the threads.