Have a look for K-nuts. They're aircraft spec nuts, no Ti but very lightweight and corrosion resistant. M6 has a 7mm hex.
M6 thread with an 8mm hex surely isn’t possible? Would be 1mm wall thickness from thread major diameter to outside face, would be way too weak?
The M6 on those still have 10mm heads mate. I want them to refit as header bolts with the new exhaust system. The rear cylinders studs are bleddy tricky to get at, so I would like a more robust / less likely to deform nut to refit. The existing fixings are M6 x 1.0 with 8mm heads, I’m worried if I go with the 10mm head, the extra wall thickness of the socket will not clear the rear shock.
Sorry, I hadn't checked out the description, but M6 K-nuts with an 8mm head are definitely available.
