Jetting

[pballer12]

I have a 06 400ex with a Hmf Exhuast uni filter wiseco 11-1 piston and a 15 tooth sprocket I have a 42 pilot jet which works great. I was just woundering if anyone had any suggestions on what size main jet to use with that set up.

[CJM]

152-155, depends alot on your elevation and temperature.

[pballer12]

I live in jersey I have a 170 in right now is that top much?

[atvrider13]

A 170 sounds fine. Are you running the lid on or off?

[DragonGunner]

Depends also on air flow....the more air flow the bigger the main jet has to be. I run 185 main jet with k&n with pre-filter an a open airbox with a pre-filter over the box. 11:1, 406cc, ported.....in cold weather I throw the lid on that has a few holes in it to cut the flow of the denser air, don't have to mess with the main jet that way. I'm at 750' also.

[pballer12]

Alright thanks guys

[Zakradu398]

I'm at 1200 ft. No lid and yosh slip on and I got a 152.5 main. Works good for me

[CJM]

Originally posted by atvrider13
A 170 sounds fine. Are you running the lid on or off?

WAY to large for just a slip on and such.

I ran a 170 in a 416, open airbox, exhaust, etc.

[pballer12]

I have the 170 lid off wiesco piston full exhaust and front sprocket

[CJM]

Originally posted by pballer12
I have the 170 lid off wiesco piston full exhaust and front sprocket

Too much. A sprocket has zilch to do with the jetting btw.

Check your plug, tan/gold/chocolate brown is good-black, wet, carboned up is bad an to rich.