This is weird, HELP ME!

[Racer#213]

Ok here's the 411. My bike runs fine in 1st and 2nd. then i hit 3rd and it runs fine too, until...you get into the higher rpms. then it just boggs down. i tried 4th too, and it did the same. but 2nd and 1st are fine. the plug is a perfect tan color. i'm running a #135 main jet, #42 pilot, and my air/fuel mixture screw is 3/8 out. It runs fine in the bottom. It's just above 2nd the higher rpms just bogg down. it's warmed up great. there IS fuel in the tank., Could my powervalve be gummed up? But wouldn't that only affect the lower rpms? That's all i can really think of. It's messed i know, but what coult it be?

 

[xnatlwrench]

two things to check
1) check your power valve, because that controls the higher rpm's by changing the size of your exhauts port
2)check to make sure all your electric connects are good and snug, if they aren't they can make a bad connection because of the engine vibrations

 

[Racer#213]

ok, but wouldn't the pz thing affect all of the gears, not just 3rd and up?

 

[cr25096er]

my friends kx100 would do the same after a few rides on the br10.5es(or what ever goofy plug they tell u to run) untill he changed it. he went to a b9es and never had that probles again.

 

[Racer#213]

i'm running a BR8ES now, but only because i'm out of BR9ES's. COuld my Main Jet be to lean?

 

[Racer#213]

all better. i had to richen my main, needle, and pilot. so i must have been quite lean.

 

[Faded]

That or dirt in the carb. remeber that taller gears place a greater load on the bike.