roadthrills
04-06-2008, 09:05 PM
I have a '92 250X. It is bored 2mm, ported and polished, Wiseco 12.5:1 piston, stock cam advanced 3 degrees (done at crank gear when new rod went on), custom built dual exhaust with straight thru cans, automotive cone style air filter & holes in airbox lid. I drilled to a 135 main jet, drilled the pilot jet to not quite a 40 (using furnace orifice bit kit), moved the needle clip down 1 position from stock, and fuel screw stock 2 1/2 turns out. At warmed up idle I have a slight putter now and then, & sometimes it will putter and die. If I rev it up in neutral and let off the throttle it takes just a bit to idle back down. Low and midrange riding feel fine, and acceleration is smooth 'til full throttle then it's like it runs out of power. It won't hit the rev limiter. When decelerating from upper rpms it also backfires out the exhaust. Any and all help will be appreciated.