250-500cc WR250 squish - slight pinging off idle when starting out

Maybe someone put a high compression race head on it. At $4.85 I'd run it 100% in everything. Just knowing it's got a little lead and no ethanol would be worth it. I run $8.50 per gal. VP110 in chainsaws, weed eaters, leaf blowers and all other 2 strokes, that way I'm not working on gummed up fuel components with decayed "O" rings and gaskets which gives me more time to ride.