I have a 83 V65, and with cold plugs, NGK 7´s, and it is still running lean and backfires easily. Under acceleration, there is no hesistation or backfire. Steady 3,000RPM and up will backfire. It´s not overheating. Running premium gas. I have tried alot of different settings of the pilot screws. Previous owner installed a Kerker header and K&N air filter. Should I go one size bigger on the main jet or one size bigger on the main and the slow jet. Fully choked it runs great, no backfiring at all.