My 2005 scrambler is backfiring alot when it first starts up. The last time I rode it, it did it for about 15 mins and went away. Now, it seems like it does it longer. Any ideas what it could be and how I could fix it. It has an hpd pipe, jet kit, and airbox mod. They were all professionally installed last year. It just started to do it about a month ago. Thanks in advance

 

Usually backfiring is a sign of a lean engine. Cold engines run leaner. Try jetting a little richer. Try plugging a little bit of air to the airbox so it richens it and see how that works. Do things change if you use the choke? Other things to look for would be maybe a disconnected vacuum line. Jetting for mods can sometimes be guesswork and isnt always the same for each atv. It may be worth it to try different jetting.

 

He is correct. Most likely is is a lean condition but also sometimes if you have a leak in the front part of your pipe it lets air in and it can tend to backfire.

 

I would check the exhaust connections as well.

They are held together by springs and can become dislodged.

My Scrammy had this problem after i rolled it and tweaked the exhaust system.

 

thanks guys, i will try looking at all of that when I get home tomorrow. I will post the results

 

How the heck do you adjust the pilot screw without taking the tank and carb off?. I cant even get my fingers in there or the shortest screwdriver I have near it. I have the polaris manual, but it says nothing on how to get inthere except to remove right cover panel. This thing is still backfiring like a B@#$%