Need help fast! Emergency jetting question!!
My cousin and his friend just piped and rejetted a 300EX. They're running an HMF slip-on and a Dyno-Jet 128 main with a K&N. Here's their trouble. As soon as they reassembled the bike they blasted it up and down the street and it seemed to run perfect for about 2 half mile trips and then it started sputtering. Idle to half throttle the bike runs fine but more than half and it starts cutting out as if the rev limiter is coming in. Also, when the bike was running well it was backfiring a blue flame between shifts (this was at night). Does this sound it's running lean or rich? They had the lid off so I had them put it back on with no change so it would seem as if it's probably not too lean. Another detail to throw in--the owner of the bike replaced the rear brake pads just last night and now they say the bike won't even coast. It acts as if the rear brake is always about half on. I had them check the e-brake because I know that if that's engaged it'll activate the rev limiter. They removed the switch and pulled the plugs off it and still no change. Is this switch a normally open or normally closed switch? They're going to try and jump the two plugs together and see if that changes anything just to rule out the e-brake limiter. If anyone has any suggestions I'd appreciate 'em so I can relay the info to my cousin.