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Discussion Starter #1
I just finished jetting my yfz and now it runs rough at steady speeds. I used the stock needle on clip #5 168 main and 45 pilot.Iremoved the spark arestor and airbox lid.I live in alabama but dont know the elevation. Any sugestions on what it might be?
 

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have you tried re-installing the a/b lid and noted the differences?

runs better with a/b lid on.. your lean .. richen your needle clip setting and/or main jet

runs worse with a/b lid on ... your rich... lean your needle clip setting and/or main jet


To richen your needle clip position, drop the clip one more clip position DOWN from the top of the needle. Do the opposite (raise the clip position) to lean your settings.

Changing the clip position changes the depth that the needle goes into the main jet hole at all throttle positions.
 

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Discussion Starter #3
It dont change much either way.It runs great at idle and revs alot quicker than stock.If you hold the throttle about 1/4 to 3/4 throttle it sounds like its cutting up.
 

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drop the needle to #4 and try it


that ought to do it.

but youll loose fuel/power

another way is to drill out the pipe, look down the exhaust with a flashlight you see a metal wall at the end. that is a thin steel wall, it needs to be removed for better high speed airflow at 3/4 to top end.
you can use several small holes or 1 large drill to remove it

another option is to must drop your mainjet to a 165

so try any of those.

the mainjet one is faster cause you dont have to pull the carb.
the drilling is longer, but you get a louder quad, which could be a neighbor problem.

wither way all these options are free.


another option is to buy a K&N airfilter and then get a GYTR needle NCVQ on clip #3 that would be about perfect but then youd have to raise your mainjet to a 170 or so.



lots of ways to fix that.

PS I am leaving for two weeks in about an hour so dont feel bad if I dont respond to your next post

HAVE a nice thanksgiving!

BYE!
 

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Discussion Starter #5
I put in a 165 main with the needle on clip #5 and the air mixture out 2.5 turns.It runs great now.

Thanks for all the help.
 
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