# Rough idle, backfire.



## Nain (Mar 17, 2010)

Hey everyone hoping yall can give me some input on this problem I've been having. My 2010 brute 750 has been stalling on me recently when idling/switching from high/low/reverse. The idle sounds good when I start it cold and it comes down from high idle it sounds perfect it only does this once the machine has been moved/warm. 

It also quite often backfires if I cut the throttle and let it come to a complete stop (seems to do this from any throttle position), it's usually like 2 small pops or backfires out of the exhaust. Now it only seems to be a low speed, low rpm problem, when I'm on the throttle it sounds and runs great.

The only mods on this bike are a Power commander V and full muzzy exhaust. I am using the fuel map from the power commander website for the 2008 brute force with K&N + muzzy exhaust. I do not have a K&N air filter in it, currently it is the stock filter.

If any of you have any ideas whats causing this? I honestly cant think of what would be effecting the idle since it shouldn't really be effected by the mods I have on the bike.

Thanks for the input in advance, appreciate any help on this issue!


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## fstang24 (Jan 9, 2010)

I ALSO HAVE A 2010 BRUTE FORCE 750 WITH A HMF SLIP ON AND HMF OPTIMIZER, AND HAVE THE OCCASIONLY BACKFIRE, POP OUT OF THE EXHAUST EVERY NOW AND THEN, ONLY DOES IT ON DEACCELERATION WHEN I LET OFF THE THROTTLE AT ANY RPM, LIKE I SAID DOESNT DO IT MUCH BUT BIKE RUNS FINE, I HEARD SO MANY THEORY'S ON WHAT CAN CAUSE THIS, BEING, EXHAUST LEAK SOMEWHERE, RUNNING LEAN CAN CAUSE THIS, ALSO RUNNING RICH CAN CAUSE POPPING, BEST THING TO DO IS DO A PLUG CHECK, PULL THE PLUGS AND CHECK TO SEE IF YOUR RUNNING LEAN OR RICH, IF RUNNING LEAN PLUG SHOULD BE GREY DRY COLOR, IF RUNNING RICH, IT SHOULD BE BLACK KIND OF OILY COLOR. iTS ALWAYS BETTER TOO RUN RICH THAN LEAN...........


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## RDs Neighbor (Jun 24, 2009)

Nain said:


> Hey everyone hoping yall can give me some input on this problem I've been having. My 2010 brute 750 has been stalling on me recently when idling/switching from high/low/reverse. The idle sounds good when I start it cold and it comes down from high idle it sounds perfect it only does this once the machine has been moved/warm.
> 
> It also quite often backfires if I cut the throttle and let it come to a complete stop (seems to do this from any throttle position), it's usually like 2 small pops or backfires out of the exhaust. Now it only seems to be a low speed, low rpm problem, when I'm on the throttle it sounds and runs great.
> 
> ...


Running rich without the K&N filter. Re map, or by a K&N filter, or maybe a UNI.


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## RDs Neighbor (Jun 24, 2009)

fstang24 said:


> I ALSO HAVE A 2010 BRUTE FORCE 750 WITH A HMF SLIP ON AND HMF OPTIMIZER, AND HAVE THE OCCASIONLY BACKFIRE, POP OUT OF THE EXHAUST EVERY NOW AND THEN, ONLY DOES IT ON DEACCELERATION WHEN I LET OFF THE THROTTLE AT ANY RPM, LIKE I SAID DOESNT DO IT MUCH BUT BIKE RUNS FINE, I HEARD SO MANY THEORY'S ON WHAT CAN CAUSE THIS, BEING, EXHAUST LEAK SOMEWHERE, RUNNING LEAN CAN CAUSE THIS, ALSO RUNNING RICH CAN CAUSE POPPING, BEST THING TO DO IS DO A PLUG CHECK, PULL THE PLUGS AND CHECK TO SEE IF YOUR RUNNING LEAN OR RICH, IF RUNNING LEAN PLUG SHOULD BE GREY DRY COLOR, IF RUNNING RICH, IT SHOULD BE BLACK KIND OF OILY COLOR. iTS ALWAYS BETTER TOO RUN RICH THAN LEAN...........


All are correct...but you are probably a touch lean. As you typed above, your plugs will tell you what is going on.


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## suzukiking07 (Jan 3, 2011)

i have a 2010 brute force and i have about 150 miles on it..i started to have a stalling issue and took it to the dealer and they found the air idle control wasnt working like it should and thats causing the stalling..just figured i would let you guys know


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