Recently purchased a 1999 Scrambler 500. The person I bought it from had installed a k& N air filter and a Aaen pipe. He did not do any jetting changes to it and I feel it is running lean. Any info on how many numbers up I should start with would be helpful. Thanks

 

I have the Aaen megaphone on my 99 too but i have the 42mm TMX carb.

Olav Aaen had told me that rejetting the carb was not maditory but is recommended for optimal performance. Usualy a jet larger will do.

I was considering just rejetting the carb but heard so many good things about the larger 42mm TMX Mikuni so i descided to order it.

I put the pipe on before i installed the carb to see how much the pipe gives me and i noticed a difference but not the kind of difference i felt once i put the new carb on.

I have also installed a single exhaust gas temperature gauge from Aaen that tells me how rich or lean it's running. At idle the exhaust gas is at 1050 degrees and at full throttle it's at 1350 degrees which is optimal according to Olav Aaen. The 42mm carb comes with a 260 main jet ( I think ) and optional smaller and larger jets.

I have not had the opportunity to check the exhaust temoerature with the stock carb so i can't tell you the numbers. I would assume it to be higher.

Chris Picciotto
99 Scambler 500

 

Thanks for your reply. You have got me thinking that I had better order a carb from your experience. Thanks