my buddy has a ds650. hes got full alba racing exhaust, bigger jet and no air lid. When he hits high rpm it misses.. Whats wrong with his quad????????[img]i/expressions/face-icon-small-smile.gif[/img][img]i/expressions/face-icon-small-wink.gif[/img][img]i/expressions/face-icon-small-smile.gif[/img]

 

Does he have a Stock CDI box. if so he is hitting the rev. limiter.

 

I can't tell (with those expressions) if you are seriously asking a question or poking fun at your buddies DS - Regardless, He's probably hitting the rev limit. There are lots of CDI boxes out there for a multitude of quads that raise the rev limit and increase performance.

 

No this last weekend my DS did the same thing, I would be running someone and at the top of 5th it would just kinda cut out on me like it was trying to die. I believe it was running lean but the plugs looked right on so I dont know but I know it wasnt the rev limiter. I just took it easy and the bike never did it again, strange.

 

the tube between the carb and air box might be collapsing

 

That is what I was thinking and I used zip ties in between each rib now so maybe it wont do it anymore.

 

The gas tank might not be venting enough. That could cause fuel starvation if it's kept at WOT for very long.