Need a little help with my jetting situation

I haven't had a 2T for over a decade, and the last one was a nightmare to figure out (94 RM125)

 

 

My 07 YZ250 is running a 170 main, and it's too rich. Spooge like crazy, smokes when riding at temperature. Only mods are FMF Q Stealth silencer. It had a PC R304 on it and never smoked, never spooged. I am getting ready to throw a Gnarly pipe on it, so to kill 2 birds, what main should I get down to to get it close? I went to my local shop and picked up a 167 and 165 main.

 

70-50* temps, 650' elevation, 36:1 gas

I haven't had a 2T for over a decade, and the last one was a nightmare to figure out (94 RM125)

My 07 YZ250 is running a 170 main, and it's too rich. Spooge like crazy, smokes when riding at temperature. Only mods are FMF Q Stealth silencer. It had a PC R304 on it and never smoked, never spooged. I am getting ready to throw a Gnarly pipe on it, so to kill 2 birds, what main should I get down to to get it close? I went to my local shop and picked up a 167 and 165 main.

70-50* temps, 650' elevation, 36:1 gas

Never seen a 167 main...

That spark arrested silencer is the problem, they spooge like crazy. For what it's worth. I run 168, 2nd clip,48 with 40:1 and a shorty silencer.

It's probably a 168. I have been playing with mixture ratios trying to lessen the spooge, to no avail. Just trying to avoid pulling the carb multiple times when I add the pipe.

I think there is a sticky that can be found that goes into detail on this topic. Pretty sure GMO397 is right, they determined it had little or nothing to do with jetting or mixture. Check the sticky out and that will help a lot

I haven't had a 2T for over a decade, and the last one was a nightmare to figure out (94 RM125)

 

 

My 07 YZ250 is running a 170 main, and it's too rich. Spooge like crazy, smokes when riding at temperature. Only mods are FMF Q Stealth silencer. It had a PC R304 on it and never smoked, never spooged. I am getting ready to throw a Gnarly pipe on it, so to kill 2 birds, what main should I get down to to get it close? I went to my local shop and picked up a 167 and 165 main.

 

70-50* temps, 650' elevation, 36:1 gas

What throttle position are you mostly at ? This is the most important aspect of fine tuning your jetting. Your main may be fine, or even a bit lean now that it's getting into fall colder temps. You may have an overly rich pilot and or needle clip position... Do some reading on the correct procedure for jetting, otherwise you can just be chasing your tail.

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