klx 250 jetting help

[aussieklx]

Hi all,

Im a new member from australia. Ive got a 99 KLX 250. Ive done all the free mods on planet klx and i have made my own power pipe, pretty much straight through. Can anyone suggest some jetting settings for my CV34. Currently the pilot screw is about 3.5 - 4 turns out is this bad. It runs ok but i want to make sure ive got it as good as i can get it.'

Cheers

[hatto]

Hi all,

Im a new member from australia. Ive got a 99 KLX 250. Ive done all the free mods on planet klx and i have made my own power pipe, pretty much straight through. Can anyone suggest some jetting settings for my CV34. Currently the pilot screw is about 3.5 - 4 turns out is this bad. It runs ok but i want to make sure ive got it as good as i can get it.'

Cheers

Hi aussieklx and welcome

Get a dynajet kit from serco in qld -new needle and jets in kit

cheers hatto

[aussieklx]

cheers hatto, is that dynOjet you mean

[mooredan]

This is a Keihin CVK34 carb, right?

Since you've turned it out more than 3.5 turns (normal is 0.5 - 3.5 turns out), your pilot jet is probably too small. You'll have to check the size installed, but it's probably a #35

The pilot jet for the CVK carb is of the N424-25 type, here's the next two sizes up:

N424-25-#38 kawi p/n 92064-1050

N424-25-#40 92064-1108

AFAIK, the Dynojet kit doesn't include pilot jets.

While you're ordering jets, get a KLX300 style needle (N1TC, collar and clamp)

kawi P/N

16009-1912 Needle-Jet,N1TC

92143-1667 Needle Collar

92037-1401 Clamp, Needle Jet

Check your main jet too, if you're less than a #125, then here's two more to get:

92063-1069 #125 Main Jet (keihin type 99101-393)

92063-1074 #128 Main Jet

Achieving the right jetting will depend upon intake and exhaust modifications and altitude. It takes some trial and error to get it just right.

There are a few tuning manuals over at my website that may help. They are for the Mikuni carbs, but the tuning principles are essentially the same.

[aussieklx]

thanks mooredan! when i get the neddle what clip position should i put it on

[mooredan]

Start out with the clip in the middle slot (3rd from the top). The "collar", which really looks like a washer, go under the clip.

The jet needle (the long skinny thing) and needle jet (mounted in the carb) predominately controls the midrange. Not midrange of RPM or speed, but when the throttle is opened from 1/4 to 3/4

Most people have found that the stock needle jet is fine and midrange tuning can be done with the jet needle.

Moving the clip up lowers the needle and makes the mixture more lean. Moving the clip down raises the needle and makes the mixture more rich.