What grade petrol should i use

vat69, May 9, 8:10pm
for an old 1975 honda cb500twith original valves and seats
i was told if i dont use the correct octane i will stuff the valves and seats because they arent hardened
thas why i sold my 72 trumpy 15 years ago.
any feedback gratefully accepted

mm12345, May 9, 8:44pm
If the valves / seats aren't hardened, then the problem is from lead-free fuel.I'd use premium fuel with additive (valvemaster) or (leaded) avgas if you can get it.
The additive won't totally prevent valve seat recession - but it does reduce it.

vat69, May 9, 11:50pm
by premium do you mean 95 or 96!the motor seems to spit misfire and splutter on it by runs ok with 91

bellky, May 9, 11:56pm
Just use 91 then.

moosie_21, May 10, 5:26am
HOW DO PEOPLE KEEP THINKING 96 STILL EXISTS!!!!!

saki, May 10, 5:43am
You sold an old trumpy just because of that.

dave653, May 10, 10:23pm
Reduce the octane. quadruple the price!