While replacing my rear strut I dropped one of the 3 nuts that tightens the top hat into the body at the strut mount behind the gas tank. Anyone knows what size is these nuts? So far I tried M8 1.25, M10 1.25 one too small the other too big.

 

That's weird. Front should be M10x1.25 and rear should be M8x1.25.

 

Hm, maybe the nut I bought has nylon lock. I'll try a regular vanilla washer nut M8 1.25.

 

A nylon lock nut should have some resistance, but a serrated flanged nut should work fine.