the other day i was riding my blaster ( which is bone stock ) down through a dirt path in a field, whenever it wound out 5th gear, i notices it had less power than i was accustomed to, when i got into 6th, there was no power above 1/2 throttle, it stuttered just a little bit , it never tried to die or anything, just quit making power.... it pulls all the way through the power band seemingly well in 1st, 2nd, 3rd, or 4th... Over the coldest part of winter, i didnt ride it at all, but i got it out and let it run for 25 - 30 minutes a week , i always rode it around slowly but i never got it up into the higher gears or anything. any idea?? oh yeah, at the recommendation of my dealer, we put it slightly thicker gear box oil during winter. other than that , it was running great? any ideas? i would say the bike will not run past 43-45 mph. a guy on a '90 stock 2wd fourtrax 300 was having no problem keeping up with me... NOT GOOD!

 

check ur plug mine did the same thing

 

You are lean!!!! Up the main 2 sizes and try again.

 

i`m not trying to be a wise a$$ or any thing but if it is RICH i will cough and make other strange nosies on top end not if it is lean
n e wayz what mods do you have and what main jet do you in

 

sorry i was not paying any attion lets just say what main jet do you have

 

i feel your pain, that happened to me the other weak, i went up to a 240 main, it came alive

 

Thanks for the help guys... It turned out to be a cheap plug that my dealer installed and an air-filter they were supposed to have replaced! I replaced the plug with a new NGK and installed the new K & N i had been meaning to, it runs like a champ now. amazing what a little breathing can to a motor!