full throttle

[400exrider0004]

i need some help. A while ago my 06 450er started cutting out when i gave it full throttle. I assumed it was something stuck in the main jet. It was running perfect up until this point so i know my jetting is right.I cleaned the jets in the carb and made sure all of my valve clearances were good. Well after i rode it, the same thing is happening. The bike runs fine from idle to 3/4 throttle, but once i get past that point it cuts out, popping, like a false rev limiter. Theres a total loss in power when at full throttle. Is this a fuel problem or ignition?

Thanks for the help and please ask if you have any questions

Josh

[d3ktrix]

Whats ur jetting?
What season was ur bike jetting in?
Did it start when the temps starting going up?

[400exrider0004]

my jetting is to sparks recommendations.

Main Jet-175
Needle-NCVQ
Clip position 4th from top
Pilot-stock
Air/Fuel screw-2.5 turns out from closed

I jetted the bike probably around the same time last year. It was running fine and then all of a sudden i have no top end. No it didnt start acting funny when the temperature changed. I first noticed it the day before Thanksgiving and it has been giving me trouble since:ermm:

[d3ktrix]

Doesn't sound like jetting from what you say.

Have you checked for air leaks on the intake boots?
Like actually spray liquid on them and see if the idle speed changes.

Also make sure the header has a good seal to the head.

[400exrider0004]

i havent checked the intake boots to see if there was leaks. I did put a 172 main jet in, but im not sure if it helped when i rode it. should i go down to a smaller size. Its just whenever i jam the throttle to wide open, it bogs, sputters everything. Like theres to much fuel or maybe not enough??? If you have any ideas go for it.

thanks

[07trx400ex]

Sounds like the clutch could be slipping.

[400exrider0004]

thats a possibility. but i think i would notice it more than when im WOT. Ill just keep going down in main jets sizes without trying to go to lean, where it blows up.

[the Z Man]

What kind of filter are you running and when is the last time you cleaned it?

[blasterfreak99]

^^ yea im thinking clogged filter too ^^

[TRX450RACER174]

IMO your main is to phat for your mods go down to a 162 or 165 and see how it runs, I have a hrc kit and am running a 165 main so without a cam i dont think you need to be that high in the main.

[400exrider0004]

i have a k&n filter and i cleaned it about a week ago. im down to a 168 main, and i am also thinking i was to fat with a 175. im going down to a 165 because i noticed an improvement going from 175 to 168. its just wierd to me that i didnt notice this when i had the 175 in. I raced the bike numerous times with this, and i never noticed it, its wierd. I think im on the right track though i hope. thanks for your guys help. i am looking for a cam also, should i get a crf cam or a hrc cam??

thanks

[TRX450RACER174]

I have no personal experience with a crf cam i have only rode hrc cams so i can't tell you a power difference.