Members who have donated towards server costs
Join Date: Nov 2007
Location: Chandler, Arizona
First of all, what are you using for air filters? Non stock "high flow" air filters will lean out the mixture, and you will need to rejet for them. The pilot screw only controls the mixture at idle, it will not correct a lean condition at higher rpms. A richer mixture at idle WILL help a lot with backfiring on trailing throttle (slowing down with the engine in gear clutch out throttle closed). I have all ways checked plugs by starting with new plugs, putting a 100 miles of combination highway/city riding on them, then reading them. Yes, you can go through a lot of plugs like that, but the plugs are still perfectly usable. When you finally do get it right, you will have a lifetime supply of plugs.
I am a motorcyclist, NOT a biker.
1997 Vulcan 750, purchased about a week ago
2006 Sportster 1200 Low
2013 Royal Enfield Bullet 500, converted to carb
2001 Yamaha XT225, heavily modified
2004 Honda Rebel 250
1979 Vespa P200E
2002 Vulcan 750 parts bike
1994 Yamaha XT225 parts bike