1995 yamaha warrior 350, high idle-wet plug

[uppd7727]

95 Yamaha Warrior, bored 20 over, Wiesco piston, WB .440 cam, titanium springs,

K&N w/precharger, FMF Megamax II-6 baffles, Hi-flo header, Mikuni roundslide carb w/ ?jet sizes.

My issues....

gas flows from the overflow tube on carb. Not constantly, but does flow a lot of gas when it does.

stutters 1/4 - 1/2 throttle through each gear, but runs smooth if I hit full throttle through all gears. Runs perfect if I go from a dead stop full throttle 1st through 6th (as if I'm racing to top speed).

Very difficult to determine if rich or lean. Header not red. After riding for 5 minutes or so, I've checked the plug. Was white sometimes and black sometimes.

Today, was riding in 1st gear for less than 2 minutes and it began to idle high, went forward about 30 feet without using the throttle(sounded like it was throttling up), then just shut off. Could not get it started again. pulled the plug- it was black and wet. Cleaned it then put it back in- ran fine.

Background- All above mods were done and ran fine for 2 years. Had to do a top end rebuild. After that, ran just fine for another year. Then had someone clean the carb and adjust the valves. Since this time, my quad hasn't ran the same. I know its not jetting cause it ran fine and the over-sized carb came from alba action pre jetted for my area and quad set-up.

Any ideas? needle jet setting?? I use 93 octane with stabilizer. Gas is fresh.

Edited February 21, 2010 by uppd7727
more information for person w/reply's

[Ajmboy]

95 Yamaha Warrior, bored 20 over, Wiesco piston, WB .440 cam, titanium springs,

K&N w/precharger, FMF Megamax II-6 baffles, Hi-flo header, Mikuni roundslide carb w/ ?jet sizes.

My issues....

gas flows from the overflow tube on carb. Not constantly, but does flow a lot of gas when it does.

stutters 1/4 - 1/2 throttle through each gear, but runs smooth if I hit full throttle through all gears. Runs perfect if I go from a dead stop full throttle 1st through 6th (as if I'm racing to top speed).

Very difficult to determine if rich or lean. Header not red. After riding for 5 minutes or so, I've checked the plug. Was white sometimes and black sometimes.

Today, was riding in 1st gear for less than 2 minutes and it began to idle high, went forward about 30 feet without using the throttle(sounded like it was throttling up), then just shut off. Could not get it started again. pulled the plug- it was black and wet. Cleaned it then put it back in- ran fine.

Background- All above mods were done and ran fine for 2 years. Had to do a top end rebuild. After that, ran just fine for another year. Then had someone clean the carb and adjust the valves. Since this time, my quad hasn't ran the same. I know its not jetting cause it ran fine and the over-sized carb came from alba action pre jetted for my area and quad set-up.

Any ideas? needle jet setting?? I use 93 octane with stabilizer. Gas is fresh.

Did they rebuild the carb when they cleaned it? Sounds like the float is messed up or something with fuel level not being consistent.

[uppd7727]

He did clean all circuits. I was thinking the float and needle were not re-installed properly.

[DirtDemon]

I'm with Ajmboy on this one, check the float. You are having both rich and lean problems. White plug = lean, black plug = rich. Depending on where the float sticks, you can either be getting too much fuel, or not enough. The high idle is also a sign of a lean condition. I would take the carb back apart and check the float stopper, make sure it and the seat are free of any debris. Also, check to make sure the pin that holds the float in place isn't bent, that would cause the float to hang up too. I would also check the valve clearance since that is the only other thing that was messed with when the machine started running funny.