I got the graphics from DUNCAN RACING(look them up on the web).Sounds like you may have a lean condition.Generally the motor getting flat like that is a sign of a lean condition.5th gear is not going to pull like 2nd and 3rd.Is the quad still gaining speed?.......

 

It sounds like you may be running a lil rich. Think about a rejet, or you could be such a bada$$ that you could be hitting the rev limiter in 5th gear.[img]i/expressions/face-icon-small-shocked.gif[/img][img]i/expressions/face-icon-small-frown.gif[/img] Doubtful but probable. Also you want to change your oil often and clean your air filter every time you take her out. Hope that hepls.

 

Thanks............Yeah i went to the website and im ordering them.....It shifts really quick from 1 to second and im accelerating pretty quick. Then 3 to 4 is the same.......still accelerating.......then when i get to fifth i push half throttle and it sounds HORRIABLE.

 

is it just like a lugging sound? I know when im not revved out in 4th and i go into 5th on my rappy, that the engine just kind of chugs along. 5th gear is so high you wont be pulled as hard as you were in 1-4th gear, 5th gear is pretty tall. check your plug see if its white, you might want to go up a size on your main, where you from? Maybee its cold their like here so it runs a little leaner then normal in cold weather.

 

If it was rich on top the pipe would not be glowing the excess fuel would cool the pipe sounds lean to me. I am Not familiar with the YFZ but try using a lit bit of choke on the big end if it clears up and speeds up its lean if it gets worse it is rich. My 2 cents

 

I would try going up on your jetting first. If the problem goes away, great. If it gets more pronounced, then at least you haven't run the risk of seizing that bad boy.

 

ok

 

sometimes small pieces from the carb get so cold and break off and then they go in between the piston and the cilinder and cause it create piston slap and it gets really hot sometimes it can happen from not cleaning the air filter

 

It sounds like you are lean, do you know what your jetting is?