Hey guys, I recently upgraded my 2012 KLX250 with the Bill Blue 351 kit and pumper carb, an FMF Q4 slip on, and an IMS replacement gas tank. My auto mechanic did the work and he's generally quite good but not truly a bike guy (and my Ducati guy wouldn't do it, lol). Everything is cool except I am getting some intermittent power transfer when I give it a good bit of throttle, up around 7k rpm or so. I went (painfully) through the warm-up period for the cylinder kit, so that's not an issue. Any thoughts on what might be causing this? Thanks.

 

Probably jetted to lean, whats your plug look like?

 

I'll check it...what would indicated jetted too lean? Thanks!

 

Assuming you are using non ethanol blended gas (blended gas makes it harder to read the plugs)



On a Very basic level your looking at the color of the plug’s porcelain tip. A white colored plug shows a lean mixture, a dark plug shows is rich. A light brown/cardboard color is optimal.
Best way to check is to throw a fresh plug in and do some plug chops. A plug chop is basically riding the bike at a specific throttle opening (full, 3/4, 1/2, 1/4, idle), hit the kill switch while riding, pull in clutch and quickly pull over to remove the plug and check color.

There is actually lots of info to be gained by reading plugs.
NGK Spark Plugs

 

Excellent, I'll check it out. Thank you!