I've got a problem where the plug keeps fouling, with a black/oily residue.
I thought it was running too rich, so replaced all the jets and needles etc in the carb, lowered the slide needle to it's lowest, and ran without the gauze air filter. But it's still doing it (maybe not so often).
I read somewhere that a lot of problems with these engines can be due to the valves (clearances or grinding needed?).
Can anyone please explain how to grind and set the clearances? I've seen the fiche but don't see any way of adjusting. I'm more used to adjustable tappets or shims on motorcycles! Or am I barking up the wrong tree? The piston doesn't appear too slack in the bore, so I don't think it's letting oil past the rings.
Apologies if this question is answered somewhere, I have tried searching first - honest!
BTW what's the recommended oil for these mesh/wire-wool type air filters? Seems to me that SAE30 would be too thick - maybe I should thin it?