Lexx slip on and jetting question

[HY400EX]

Lexx slip on and the stock air box lid on. With a stock 2004 400ex at 2000 feet elevation. What would be a good main jet?
I have a 155 Keihin would that work?

[Rkangel7]

I run a 150-152 main jet with the lid on, K&N filter and Lexx slip on with quiet core installed. Still needs a little carb tweaking, but runs pretty good.

[HY400EX]

Originally posted by HY400EX
Lexx slip on and the stock air box lid on. With a stock 2004 400ex at 2000 feet elevation. What would be a good main jet?
I have a 155 Keihin would that work?

I have the stock 148 & a 155. I have not installed the Lexx slip on yet. So should I buy a different size jet. Or try what I got?

[Rkangel7]

There are a lot of guys running a 155 with a slip on and filter, so it is a pretty safe starting point. You could start with that and check the plug color.

The quiet core will also have some affect. I have to run the quiet core to meet noise restrictions in the dunes, which is why I'm running a jet size in between.

[HY400EX]

I forgot to mention the climate I am in ny. I will also be runnning with the quite core in. Sounds like the 155 will work. Just might be a little rich, which I guess is ok.