jetting for fmf pipe

[lawjr]

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I have a 2000 yz250 and have recently installed a new FMF fatty pipe. Now I am fouling plugs like crazy. Any help on jetting or adjusting?

 

[Body Cast]

FMF jetting center

fmfracing.com has a jetting center that should help
http://www.fmfracing.com/jetting_center.aspx

 

[Bizerk]

Yup...you beat me to it bodycast...

FMF jetting recommendations are based on the following conditions: Premium grade pump gas with Silkolene premix, 32:1 ratio. Sea level to 2000 feet above sea level. Temperature of 70 degrees Fahrenheit with average humidity.

Your choice: YAMAHA --> 2000 --> YZ250

Jetting Information
Main Jet: 170
Pilot Jet: 50
Needle: STOCK
Needle Position: 3RD
Power Jet: N/A
Air Screw: 1 :thumb:

 

[souphmars]

when does it foul the plugs??

 

[souphmars]

i have a 98yz250 with a fmf pipe and silencer
main-168
pilot-48
3rd clip on needle
i live in tennessee also, it took some trial and error to get the this right-
i also probably use a different mix than you, which plays a role also

 

[lawjr]

thanks

my bike is fouling plugs on the slow ride in on a trail probably a 2nd gear trail. It takes about 12 minutes to get in to the riding area. Once I am in i have a real bog and trouble on the restarting of the bike. I have to open the throttle wide and kick it to get it started. Any suggestions? thanks