MXSparx

Mr. Meltsomeglass
Jul 25, 1999
3,724
71
NoVa
Took the carb apart because someone left the fuel on and gummed up the carb. Cleaned everything and replaced the pilot jet. Starts 1st kick with choke on. Once warmed up and off the choke it doesn't want to idle. Opening and closing throttle gives you popping and blue flames out the exhaust. Any ideas where to start??
 

whenfoxforks-ruled

Old MX Racer
~SPONSOR~
Oct 19, 2006
8,129
2
Merrillville,Indiana
Check, clean and adjust the ap circuit and especially the ap squirt when it clears the slide. There is a leak jet in the bowl to deal with also. Now if you want the flames, thats another story? Vintage Bob
 

Rich Rohrich

Moderator / BioHazard
LIFETIME SPONSOR
Jul 27, 1999
22,839
16,904
Chicago
John - If you can get it to idle better when hot by pulling the choke up a bit I'd start looking for air leaks. Take a close look at the o-ring at the base of the pilot fuel mixture screw, check the hot start isn't hanging open, and blow a little propane from a hand held torch near the intake manifold to see if it changes the idle behavior.
 

MXSparx

Mr. Meltsomeglass
Jul 25, 1999
3,724
71
NoVa
Thanks guys. I found that I forgot to tighten the bolt that connects the header pipe to the back half of the exhaust when I put the sub frame back on. That seemed to get rid of the flames and some popping. Does that even make sense?
 

Rich Rohrich

Moderator / BioHazard
LIFETIME SPONSOR
Jul 27, 1999
22,839
16,904
Chicago
Makes perfect sense. Pulling cool oxygen rich air into the exhaust stream can reignite any remaining unburned hydrocarbons and make some cool flames.
 
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