Stupid jetting question... I think

Alright... I finally got some Xmas money and bought the DJ jet kit for my 2002 DRZ 400s (Mikuni). The instructions say to" make sure it's the main jet your replacing" but doesn't tell you which one is main and which one is pilot. I couldn't find a pic or anything anywhere and the new jet fits several different places. Please help. I need to get the bike back together tonight. I can't read the numbers on the old jets too well, but the highest one (with the carb upside down) says 150. I bought the bike used from a guy who rode mostly up high(5000ft and above)

I believe the 150 would be the main jet.


I believe the 150 would be the main jet.


150 would be the main on a mikuni

pilot is prob 22.5 or 25

In the 3x3 Master thread, there is a document with pictures.

I used that to get an idea of which jet was which.

Here's a picture of my carb, with the Pilot Jet in focus:


The main jet is bigger than the pilot jet. In the pic above, it's the larger jet in the middle. The pilot is off to the left.

Thanks guys.. I have the DJ kit but the biggest jet in there is a 136.. I'd like a 140. I guess you have to buy that separate. Wow... 50 bucks for a needle and a clip. I guess the plastic case is pretty handy!! and I got 2 Dynojet stickers!! I'm a little confused why I need a smaller jet (had a 150) when I opened up the box (3x3) to let more air in. Wouldn't I need MORE fuel??

Thanks again


The DJ needle is thinner, so it lets more fuel pass the main jet. That's why even with the extra air, you're going down in main jet size.

When I installed the new needle in my Mikuni, I found the jets I need at a local bike shop. Just bring the old jet with you for comparison. You shouldn't pay more than $3-5 a jet.

Ah Haa!! I knew there was a simple reason. Thanks. I guess I should change my avatar. I just noticed it was my old KLX300. Which was a great bike by the way, but now that I passed the big 4-0, I'm loving that electric start.

so the jetting is different if I have the Dynojet or the James Dean?

I have a Keintech fuel screw too instead of the problematic Zip Tie, anything I should know?

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