I was at Glamis this weekend on my DS and every time i shut it down and as soon as the motor stopped it made a very muffled pop, kinda like a backfire but very soft and mellow. I raised the clip all the way up and it still did it. Any ideas? i normally run at 5000 to 6000 feet elevation and no problem...........

any suggestions on the cause would be greatly appreciated.

thanks

 

Its usually unburned fuel in the pipe that is igniting. I've never heard of this problem when running an end cap with a stock pipe, I usually hear about this with some of the Yoshimura pipes. You might want to check your jetting, you might be a tad rich. As long as its not an engine backfire when the motor is running - which would indicate the opposite, a lean condition.

 

Its usually caused by a lean condition in the idle circuit. You can confirm this by pulling on the choke when you shut it off. If it stops poping, then you have a slightly lean idle circuit. Check for exhaust and intake leaks. If there arent any leaks, then id go 1/4 turn more rich on the mixture screw.

 

I would say your way to rich...I read your other post and it says your runing a 165 main in your TM45. Thats extreemly fat for even a stage 3...let alone just a end cap. Fatest main I ever ran when i had the 45 at 1000' or less was a 152. Time and again I would go back to the 150 cause it just made the best power.

edit:
Oops...that wasn't you that posted the jet size at 165...sorry bout that [img]i/expressions/face-icon-small-blush.gif[/img]

 

Hmm must be a mix up, i have the stock carb on there with stock jetting

 

Yep..my mix up sorry