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Discussion Starter #1
i have a 99 sportsman 500 that recently started acting like it has no power when you put the throttle on but som times it works fine for a few secs. :hmmm:recently it did have some bad gas go though the carbs but it ran fine and have put a tank of fresh gas in it and been running that fine up in-till two days ago when out of the blue this happened. could it just be a fuel problem like carbs are gummed up or is it something more sever any input on this is greatly appreciated thanks
 

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Welcome to the board!
 

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I'd say its time to pull the carb off and give it a good thorough cleaning. Check the air filter and spark plug while your at it. Good Luck.
 

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Before you break down the carb

check inside your air filter compartment for the small breather hole on the upper left hand side (facing fwd). Ensure its not clogged and that it even has a sponge filter over it. When i got my used '98 sporty the foam was on the lower right side. I read over the manual (amazing what you can learn that way!) and it specifically states not to put it on lower right but instead over hole on upper left. When i moved it (after cleaning sponge w/soap & water & allowing it to dry) it ran much better, mine would sputter at mid-range and had no upper. Now it can reach 60 on a flat surface, more than fast enough!! :cowboy:
 

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Discussion Starter #5
well cleaned that carb really good today cleand the ait filter and no difference :ponder: any other thoughts
 

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Check the exhaust cam lobe.
 

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That's right .. check the exhast cam lobe.. to do that pull the spark plug out and remove the valve cover.. and use the pull start to turn over the motor.. and look at the exhast cam / lifter for enough action.. The cams can wear and not open the exhast enough..
 

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It will back fire through the carb if the cam is bad. Might try changing the spark plug also another tip unscrew the plug cap snip of 1/4" off the coil wire and reinstall the cap

Sent from my SPH-D710 using Tapatalk
 

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Discussion Starter #10
well its not back firing so tomorrow ill try new plug and maybe a new gas filter see if that helps maybe even new air filter
 

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OPT (from ATVConnection) says

in similar cases a carb kit or at least a new needle and seat are needed, not just cleaning a carb. Here is a link to a pic of a bad exhaust cam: http://i1311.photobucket.com/albums...6905C4CD-411-0000002E1B093495_zps832eb542.jpg

Not all of them fail, a combo of bad heat treatment and poor oil maintenance leads to the wear on some. I have a '98 with the original cam, runs good up to 60mph.
 
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