KLX 300 jetting

We just got a 340 kit installed in one of our bikes and we can't seem to get the thing running. Besides the kit, it has all the free upgrades, Uni filter, and the stage 2 jet kit from Dynojet. We set the bike up per the spec sheet that was included in the jet kit, but it keeps fouling the plug and won't hit a lick. He's getting a high-flow header pipe tomorrow, so I just told him to wait until it's installed before we waste a bunch of time troubleshooting.

btw - the bike was running when it came home from the shop.

Is the suggested main OK for this combination? It seems to be running REALLY rich, but some fiddling with the fuel screw really didn't help either. Maybe just hold out until the header pipe is installed and go from there? I'm guessing that it makes a big difference in the jetting. :naughty::naughty::D

Recently, the needle that Dynojet has been sending out is too large in diameter where it goes through the slide. So, the needle rides high in the slide, creating a rich mixture. Use a micrometer and measure the diameter of the needle at that point and then get a drill that is just slightly bigger. I'm talking only a thousandth or two larger. Drill out the slide.

Maybe one of the guys that has had this problem will post the drill size he used.

Ride on


That makes sense. The guys at the shop were dogging the kit out - saying that the needle looked funny. Maybe you're right. I just told them that the key to the kit was the needle profile. Little did I know. We'll check it out tonight.

The dynojet kit comes with a #32 drill bit for the slide lift hole. Check out there web sight for instruction.

I believe the dynojet needle mic's out at .118", the only size bigger I could get ahold of was a .121" the bike runs just fine.

I had the same problem running really rich. I drilled out with a 3/32" drill bit and then it worked.


use a #31 drill bit .119 dynojet needle .0118 look inside your carb.

and make sure your clip on the needle is seating all the way down, don't drill

it out unless you have to.. sounds like more dynojet problems ..

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now