Need help with carburetor jets

[KeboPR]

I recently installed a Big Gun exhaust system (Pipe + header) to my XR650L  and I was wondering if you could recommend me a proper combination for the carburetor jets. 

Sorry if you have a hard time understanding, English isn't my first language. 

[scott-m]

You probably need to raise the needle (lower the clip one or two grooves) and go to a bigger main jet. Buy the next 4 larger main jets, and put in the biggest one first. If it runs clean at full throttle with no black smoke or soot on the muffler, you are done. If it runs rich, like it has the choke on, go down one main jet size at a time until it runs clean and strong.

Edited October 28, 2014 by scott-m

[Denn10]

what else has been done to bike?? was it bone stock before exhaust install ???

[ScottRNelson]

You probably need to raise the needle (lower the clip one or two grooves)...

The stock XR650L does not have gooves or clip positions in the metering needle.  You can get one from Factory Pro that does, however (that's what I have).

 

To the original poster: there is a FAQ at the top of the page.  In there is a link to the PDF file for "Dave's Mod".  Follow those instructions and you'll have done everything you need to do to the stock carburetor to make it run better.