# 06 BF - sudden missing..backfires..poping at all rpm



## ChrisEK (Jan 19, 2011)

06 brute force 750. Snorkels..jetted..its been running great for probably a couple hundred miles after jetting. I took it out the other day and it was running fine..i go thru alot of water just like normal and not problems at all. Later in the day i go hauling off down some trailer at a decent speed and it was bumpy so i was on and off throttle alot. Id said a mile into the trail i start getting poping and backfires out the exhaust at all rpm ranges. Idles fine but as soon as u come off idle its poping and missing. I pulled the carbs apart to look for any obveous problems and didnt really see anything. Covering the intake snorkel with hand doesnt change much..and moving the choke doesnt seem to change much. Replaced plugs with new and are black again already..help!


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## wyo58 (May 13, 2011)

IMO you have too much fuel getting in some how. Usually not always, if your backfiring out the exhaust your rich, if it's out the intake it's lean. But I think you have proved it's rich from the plug state! Was it the water or the bumpy road that changed it? Some how you have more fuel getting in than you did after the jetting. Does it idle ok ?


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## MeanGreenMan (May 24, 2010)

+1.
To check whether it is running too rich or not, remove the air box cover and run the engine for test purpose ONLY. If engine runs better with the cover off, carb is running too rich because of whatever reason. So, start from there.


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## ChrisEK (Jan 19, 2011)

I was on the bumpy road when it started having the problem..i didnt run it with the airfilter box cover off yet. Will try tonight. Could the black plugs because by an ignition problem..maybe spark dropping out..?? If so..how would i check ignition side..


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## ChrisEK (Jan 19, 2011)

Ok..just got home..pulled air filter cover off..will go to higher rpm before poping and missing. It will idle..but the little idle adjuster..with the cable..is all the way in for it to..


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## wyo58 (May 13, 2011)

It has to be leaking fuel in somewhere that it shouldn't be. If it idles fine then the idle circuit is ok, probably in the needle and mains.


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## Muddy Brute Force (Dec 17, 2008)

Is your belt light flashing or on while the engin is running?, it's possible that you could be in limp mode.


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## NMKawierider (Apr 11, 2009)

If you have the idle control all the way in to idle, that's an indication she's either having trouble getting fuel...as in very low float level or she's getting so much fuel it needs the butterfly open that much to get enough air to go with the fuel its getting. Black plugs say she's rich or...some poor ignition..as in water in connectors or coil connections. Check all connectors even on the CDI. Check for water in the tank, check for supply issues...pump pressure and supply. While looking, check the carb boots for splits around the clamps. One other issue Brutes have are stuck or leaking choke plungers. Check those and the cables.


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## ChrisEK (Jan 19, 2011)

Well..another update..all connections looked good. Drained gas tank and filled with fresh fuel..no change. its going to the shop now that did the jetting on it. He seems to think its a problem in either the valves..which have never been adjusted by me or previous owner..or a problem with the chains and timing...either way at 1550 miles i think its time for them all to be done. Hopefully it will be simple and i can get back to riding.


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## blue beast (Feb 16, 2010)

im gonna guess the choke plungers are stuck.. and your getting more fuel from that...


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## ChrisEK (Jan 19, 2011)

bringing back an old topic..but postingt he fix..it needed the chains and tensioners. runs like a champ now!


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## Bama Bogger 424 (Feb 23, 2012)

About how much does it cost to fix that I think mine has the same problem.


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## wmredneck (Dec 6, 2011)

blue beast said:


> im gonna guess the choke plungers are stuck.. and your getting more fuel from that...




That would be my guess. Or theplugs aren't firing. Did you try a spark test?




Wishing I was home instead of on the road using TapTalk


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## dalguard (Oct 12, 2011)

I had the same problem last month. Turned out the air box drain was full of oil(from a roll over). When I'd go over a decent bump the oil would splash and go down the front carb. ATV would run like crap until I cleaned the carb real good.


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