Jetting KLX250s--Straight from Kawasaki (Technician)
 

Today I called the Motorcycle Dealership whom has a previous technician from Kawasaki.

I asked him what i could do to increase the power on my bike and he stated that the 09 KLX250S is a small bike and due to the small valves it is very limited in performance.

JET Kit--When i asked him about increasing the power he said "Go up 2 in the pilot from 40 to a 45 (they increase by 2.5 each size) & go up 2 in the main.
LEAVE THE NEEDLE ALONE!

DOES ANYONE AGREE WITH THIS STATEMENT?

I'm calling BS.
Is that you "Muffler King" ???

As an accomplished profiler of the Muffler King, I say no. :D I noticed only a similarity in moniker, but absolutely none of the surley, condescending tones that were common with 'Pipe Hype Travis' :)

I would agree with the main jet, but not the pilot or needle.... i upped my pilot and had to go back to stock. i put the better adjustable needle in too.

I love all these "technicians" giving their two cents.. It's like the car dealership salesmen. Most of them don't know too much - especially about performance.. I'd take whatever they say with a grain of salt.. I'd trust the wrench monkeys on this site over them any day.

Go with the cumulative wisdom of this forum. Do a lot of searching of jetting threads and take notes.

Ok. I thought they would know and just asked. Who knew they would be completely wront:(

Who is the muffler king?

This is from Pete Bothwell at Mission Motorsports, CA. He is a well respected technician there so i asked him to see what "wisdom" he would offer. Supposedly he was with Kawasaki for 10 YRS!

The "muffler king" is a term of endearment we used to use for Deej. If you want to get on his good side start calling him "muffler king" he really gets a kick out of it. :)

Take all the jetting advice and use it as a starting point. Your Kawi dealership guy probably is a smart cookie, (or maybe not) , but he probably didn't work on little 250klx's much. The guys on here have found what works for this specific bike, but you will still have variations, because any number of factors affect the jetting. Search jetting on here to find the best starting point, and go from there.
Dan
All hail the Muffler King

Something as simple as how much oil you use on your air filter can alter jetting needs. We all agree that OEM jetting isn't even proper on the OEM bike.