2012 Yamaha YFZ450 Sputter issues

[EV-2012YFZ450]

Hope someone can help: I’m having the same issue with both of my new quads and I’m not sure what the solution is. Both quads are sputtering heavily when accelerating (regardless of gear) and now even having issues climbing any sort of hill even in 1st gear, it’s as though I was trying to ride it in to high of a gear…it just dies. Took it into the shop and they said they couldn’t replicate the problem, they thought maybe the chock wasn’t all the way in. That wasn’t the issue because I just took it out this past weekend and the same problem again. They performed a major service on the bike (Inspect & adjust valves, replace spark plugs, oil filter, inspect battery, etc etc). It’s having this problem more often in higher elevations (3k-5k) feet, but was even doing this out in the desert so it can’t only be an elevation issue. Dropped it back off at the shop on the way home…Anyone have any suggestions? Very frustrating

[Ajmboy]

Maybe not enough air? How's that air filter?

* Added manufacturer to thread title.

[Mudflap64]

Air or bad fuel. If it's happening on both machines I'd change the fuel source. Clogged air filters if they are exposed to the same riding conditions...maybe junk in the gas clogging up the filters. I didn't catch what quads you have, but it sure sounds like an environmental issue for them, with both experiencing the same symptoms.

[rappy97]

Muffler bearings, for sure.

[skitchin1]

is it carb or fuel injected.

re jet it or get a programer.

what mods do you have.

hit the central up.

or what rappy said muffler bearing.

[EV-2012YFZ450]

Thanks for the replies, it's carb not fuel injected. The shop adjusted the flow height yesterday thinking that might be the issue since its mostly having this problem on an incline. They keep saying they haven't seen this before so it's sort of a trial and error at this point. Who knows, I'm losing faith in them quickly.

[quadnut20]

Thanks for the replies, it's carb not fuel injected. The shop adjusted the flow height yesterday thinking that might be the issue since its mostly having this problem on an incline. They keep saying they haven't seen this before so it's sort of a trial and error at this point. Who knows, I'm losing faith in them quickly.

Have they checked the TPS aka throttle position sencer or tried rejetting it ? I would never let a Dealership touch my quads jmo

[skitchin1]

any mods done to it if so it needs to be jetted. where on the throttle is it sputtering. idle to 1/8 is pilot, air screw will tell you what size you need. 1/8 to 3/4 is needle, 3/4 to wot is main jet.

hit http://www.yfzcentral.com/ up they can help you a lot more. and maybe tell you what size jets to use.

Edited July 1, 2012 by skitchin1

[manual369]

Did u find out what the problem was I am also have trouble with my 2012 yfz carb model

when I go out to ride it runs good for a few minutes

but 20-30 mins of trail riding I go to wot and it cuts out very bad

won't climb any kind of hills at all

I even got beat by my buddys 300ex lol