Current thinking over here in NZ is to run avgas/91 @ 50/50 mix. I have tried it and it seems to be ok and rev slightly better. Was originally running pure avgas but have just changed. Mind you there is no airbox fitted so I don't know whether that would enter the equation. Have just taken the front piston out and the burn seems even after about 300Km (about 190 miles) at track speeds. Plug colour seems to suggest that the mixture is o.k.My bike is running with RS250 ignition and coils but I haven't identified the pistons yet (oh the joy of owning an old 2 stroke) with so many variations.
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