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Big Bore jetting issue

1011 Views 4 Replies 4 Participants Last post by  SamUK
I have a 2004 Honda Rancher 350 with a big bore and high flow exhaust I just put a bigger slow jet in to get it to idle but it doesn't run right when you give it throttle. With the high flow air filter off and the air box open it runs great but as soon as I put it back on it doesn't get enough air. The air mix screw is 4 1/2 turns out. Any suggestions on how to get more air through with the air filter on?
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Have you adjusted the A/F screw correctly?? If it's not getting enough air with the filter on (Running rich) then you need to go down on the pilot. I'm assuming it's running rough below like 1/4 throttle or so....
Have you adjusted the A/F screw correctly?? If it's not getting enough air with the filter on (Running rich) then you need to go down on the pilot. I'm assuming it's running rough below like 1/4 throttle or so....

I upgraded the pilot jet and that fixed my idling problem. It idles fine at 4.5 turns out on the air fuel screw. There's just now power unless you either take the air box off or have it open. If you put the cover on with the air filter it chokes it out. By going down in the pilot how would that help? I moved the needle E clip all the way to lean and nothing is really working. It runs rough at all points in the throttle position when the air is restricted by closing the box.
The main jet is way too big. Put the needle back to stock. Get one sized larger pilot jet because 4.5 turns is too much. Half to about three is normal adjustment .
I agree 4 1/2 seems to be a lot of turns, Im sure stock recommendation in the service manual is 2 1/4 out.
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