FUEL SYSTEM PROBLEM, CARB. SPUTTERS AT HIGHWAY CRUISING SPEED. NEW STAGE 1 INTAKE. V&H EXHAUST. REJET OR OTHER PROBLEM?

mleach72

mleach72

Well-Known Member
QMChief said:
076 MAIN 031 INTERMEDIATE
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That sounds about right. You might want to try a 78 on the main jet and see how it feels. I would say your problem is most likely the auxiliary plug needs removed since you changed the air cleaner.
 
mleach72

mleach72

Well-Known Member
QMChief said:
I HAVE A NEW 0295 FOR DOWNSIZING THE 031 IS THAT RECOMMENDED?
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The 31 is probably the most common intermediate jet, but every bike is different. Make sure the auxiliary plug is removed. If your still getting the same problems, try the .0295.
 
QMChief

QMChief

Member
Since I have the filter off I'm going back to the teardrop and downsize to 295. The bike was running rich the whole time, I thought a filter upgrade would help but apparently not.
 
mleach72

mleach72

Well-Known Member
QMChief said:
Since I have the filter off I'm going back to the teardrop and downsize to 295. The bike was running rich the whole time, I thought a filter upgrade would help but apparently not.
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If your new air cleaner is blocking the main vent, and the plug isn't removed, it will cause all kinds of problems. When the fuel level falls, it will create a vacuum in the bowl. That will create a lean condition. When the needle jet opens, the incoming fuel will compress the air in the bowl leading to a rich condition. The bowl MUST be able to breathe.
 
QMChief

QMChief

Member
I have that cv to G carb adapter I don't know how well it lets the vent breathe but it looked like the slit was over the vent hole and all was well. I also found out my exhaust wasn't as tight as I would want so it may have caused the backpressure problem Mr. Wright pointed out. I'm going back to square one to see if the exhaust was the problem since you said the normal jets are in place. Mr. Wright or mleach72 would some backpressure issue cause it to run lean? I want to clear the plug problem and maybe that is my highway speed issue as well.
 
mleach72

mleach72

Well-Known Member
QMChief said:
I have that cv to G carb adapter I don't know how well it lets the vent breathe but it looked like the slit was over the vent hole and all was well. I also found out my exhaust wasn't as tight as I would want so it may have caused the backpressure problem Mr. Wright pointed out. I'm going back to square one to see if the exhaust was the problem since you said the normal jets are in place. Mr. Wright or mleach72 would some backpressure issue cause it to run lean? I want to clear the plug problem and maybe that is my highway speed issue as well.
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Even if your main vent isn't blocked, removing the plug won't hurt anything. The only reason it's there is so no fuel vapors leave the carb. It's a dumb EPA thing. If your running open pipes with no baffles, the main jet tends to come in too early, which would cause your rich condition. Maybe try moving up to a 60 air bleed as @41bigdawg suggested. That will bring the main jet in a little later.
 
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