Jetting for 03 YZ @ 4500 feet

[kawi72]

Hi, I am currently running stock jetting on my 2003 YZ 250 with an FMF Fatty pipe and Turbine Core 2. It runs good at sea level but I will be racing at 4500 ft.
Can someone please offer some jetting advice?
thanks,
Jim

 

[426 Pilot]

After talking to you it sounds like you needed air more than the bike did..... :ride:

 

[motojonny]

168 main and 42 pilot should do the trick. I have the same bike and run a 165m/ 42p and it's a little rich for Vail, but works good in Denver(mile High City)

Just curious if your using stock suspension or got a revalve and for what type of riding?

Thanks,
MJ

 

[super rat]

Johny Electric?

 

[whistleryz]

up here in canada, around 2000' and higher I am running a 172 or 175 depending on the time of year, I do lots of riding over 4000' on mountain passes and the jetting is great . I have left the slowjet and the needle jet stock

 

[Studboy]

At 4200' ASL, here are my specs for my 02 YZ250 (this is for the stock pipe.)
30-60 degrees 172 main, 40 pilot.
60-90 degrees 170 main, 38 pilot.
90-100+ degrees 168 main, 38 pilot.
These are all with the stock needle, 32:1 mix, pump gas.

Do a plug chop, not all bikes or fuels are the same. This should just give you a good baseline to start with.