Had a customer bring a 08 Scrambler 500 into my shop that just ran awful and was backfiring. He had the bike all apart looking for the problem including cleaning the carburetor. The very first thing I did was buy a service manual. After several days looking for the problem checking all the electrical parts of the bike and not finding the problem I decided to recheck the carburetor. He had done a very thorough job cleaning the carburetor. The only thing he didn’t do was remove the idle pilot jet because it isn’t serviceable. I drilled out the plug over the adjusting screw and marked and removed it. I then cleaned out the low speed circuit and then put everything together. The bike ran perfect. So if you are cleaning the carburetor don’t over look this low speed idle pilot jet even if the service manual says its not serviceable..