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ok. I have a 2007 yfz450. It has a full big bun exhaust, 170 main and a 45 pilot, with air box mod and lid removed. I just completed the exhaust cam mod (wicked gain) and bike seems to be running great with the exception of a time to time backfire when bike almost comes to an idle. Before I went on a ride I put a brand new spark plug in. When I got home I check the plug and it was very dry and light in color. What should I do? Bigger Pilot? bigger main?????????????? Pipe did not seem to be hotter than normal.
thanks for the help.

 

yea sounds like its a little on the lean side, i would step it up a size or two.

 

Are you thinking pilot jet or main jet or both?
Thanks

 

Main jet.

 

yepper main jet, you shouldnt have to mess with the pilot.

 

put in a larger main and that worked. No more dry plug.
thanks alot

 

good deal