Kawasaki was at my dealers working with their exhaust gas analyzer and a dyno. I took my bike in to have the Dynojet kit installed since I put the Two Brother exhaust on. They ran my bike on the new equipment.

I see here that most people went with the .128 jet. It appears the stock jet was a .018. The high-tech analyzer showed that the correct jet was a .120 - anything more would have been too rich and cost power. (we area at sea level)

Kawasaki said .128 is way too much jetting for the main - since everyone seems to be pleased with the .128 I wondered how you arrived at that choice.

Rik

 

your probally stock, where as the 128 is mainly for bikes with intake and exhuast mods. i have a 128 in right now with uni filter and no snorkle, just a touch too rich.

 

Nope.....Two Brothers carbon fiber exhaust and KN intake filter with air box open

Rik

 

Keep in mind that the dealer is likely trying to keep you emissions-legal. That's the reason this bike is jetted so lean from the factory (to meet EPA standards). If you pull the snorkel and lid, you're letting in even more air... I don't understand how going up only one jet size would richen up the mixture enough to make it run good. With a full exhaust, aftermarket filter, and the lid off, I couldn't imagine how crazy-lean you are running your bike with a 120 main.

 

Can you provide more details (what type of analyzer, temp, humidity, results, etc).

I don't doubt the results. At 5300ft (where I live) I had terrible results with a 128 main. I settled on a 122 for a while (didn't have a 120) and eventually went back to the 118 (at higher altitudes a 115 works better). That's with a full exhaust (Big Gun), K&N Filter and the KDX Snorkle. I thought that maybe the 128 would work at sea level, but now I don't know. I'd like to know more about how "they" arrived at the decision you had too big of a jet.

 

#138 Main.

 

#150

 

It's alway better to be a bit on the rich side, so you can run cooler. I have a funny feeling that the dealer is missing something or chasing a unrealistic A/F ratio. My dealer over here in Japan runs a 250cc D-tracker with open airbox and full Nassert exhaust. He gets the best results with a 130 main.

Like one of the other posters said, your dealer might be staying with emissions. I didn't notice any power figures in your post, so maybe a certain A/F ratio is his goal?

 

Not here. Kwaka service dept actually recommend a #138 main ...

 

There is a big differnce between the orifice sizes of keihn jets and dynojet jets and mikuni jets. The numbers do not jive. There is a post on here of the respective numbers ot orifice sizes of each maker