2Stroketwin666

165 on main 50 on pilot I’m at 500ft above sea level

93 octane on premium here

Yes hole starting so figure lean condition on that side

Recently built the Athena 421cc 4mill stroker here’s the list cool head 22cc domes, 68mm Athena big bore cylinders with clean up port, wiseco pistons, hot rods 4mm crankshaft, vforce 4 reeds, 34mm pwk carbs with billet intake, toomey T5 exhaust, dyna tek programmable cdi and coil, k&n pods, lockout clutch from F.A.S.T. Larger radiator. spark plugs started working themselves out, checked compression after build had 150psi after 5 hrs on new engine have 80psi. Pistons and domes are ruined cylinders are still good. Here are pics. What did I do wrong? Don’t want to get new parts and have this happen again. Oh and running ethanol free premium, should I have been running race gas?

Finishing my build it’s a 06 banshee just installed 421cc 4mm stroker with lockout clutch, pro design cool head with 22 domes, wiseco forged pistons, hot rods 4mm crank, upgraded radiator, toomey t5’s, vforce4 reeds, keihin pwk 34mm race carbs, k&n air pods with outerwear’s. Billet intake, trinity stage 4 adjustable timing plate set to +4. I’m new to the pwk carbs and wondering where to start with jets and needles I ride at 0 to 500 feet elevation. Any help would be appreciated, thank you!

Bought my banshee new in 06 and the stock pistons finally gave up so I decided it’s about time for an upgrade. Bought the 421 Athena big bore stroker top and bottom complete kit from bp racing. Any advice on installing this kit would be appreciated. Also I’m sure I’ll need bigger carbs anyone have suggestions for a carb kit that will work well with this setup that won’t break the bank.