I just bought a 2003 yamaha warrior, it has a FMF titanium 4 exhaust and K&N filter.

I took it out to the desert today at about 3/4 throttle it starts poping and cutting out otherwise it runs great. When I rode it the day before at the sellers house It seemed to run okay.

The person I bought it from said they had the Yamaha dealer install this pipe and rejetted the carb when it was new.

the dealership location I am guessing is at 800 ft above sea level, I am at about 2800-2900 ft above sea level.

So my question is could it be a jetting problem? or?

any help would be appreciated

 

this does sound like a fuel/air mixture problem. call the stealership nearest to you and tell them what is going on and what altitude you ride the atv. have you checked the spark plug? it would run rich at a higher altitude, so the plug would be darker than normal.

 

i had a 01 warrior and it sounds like you have the same problem i did but it might not be it. look at the air boot that goes between the carburator and airbox if its loose then that can cause the problem at high rpms.

 

First of all I removed the air cleaner and it is not a K&N like the seller said. It also looks like someone bored three 3/4-1 inch dia. holes in the top of the air box.
I removed the boot between the box and airbox. I sprayed the inside of the carb with carb cleaner while it was running. There is no mis-fire or cutting out when you rev it up when it's not under load. I spoke to the stealership where they supposedly did the re-jetting and the service guy said that I was probably up against the rev limiter? I know half throttle in any gear is not up against the rev limiter (i'm sure at this point something is wrong this quad just starts to pull then it craps out). I called another service shop and he seems to think something is wrong with the high rpm circuit in the carb, like something is gummed up: that could be possible because supposedly it hasn't been taken out and ridden wide open in a long time, just up the street a little bit (who knows) since the owner lied about the air filter that she supposedly paid 60-70 dollars for, and has only taken it out for 2 big rides (I hadn't even noticed when I bought it that the grips are all worn down on the top). I am going riding tomorrow, I am not expecting any changes with from the carb cleaner. Also I topped off the tank the other day with 87 octane, I just read that this requires 91 minimum.

Any ideas/thoughts would be appreciated.