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Discussion Starter · #1 ·
Got a couple more questions for you dudes.
What does raising/slash lowering the needles in the carbs do. (lean/richen) also If I bore to 650 on my 85 do I need to put bigger or smaller jets in? Or do I just leave it alone.
Thanks again
 

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lowering needle by raising clip=leaner
/example, clip on top notch would be the leanest setting. Don't put clip in top or bottom, may cause throttle to stick, better to buy next size leaner/richer needle if extremes needed
 

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bore you 650? how much, if do do like .10 over thne u wouldnt have to, but if yu go alot at one time you might want to. jsut check the plugs and if they white, richen, if brown perfect, if black leaner
 

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you should leave the needle alone, do all your adjusting with the pilot and the main jets and the air screw, find the "basline" for your sled, a good manual will have this info, moving the needle makes a huge diffrance sometimes too much to compansate with jetting, and if its to the lean side it can spell disaster, now im sure some people here will disagree, but if you spend the proper time to jet and play with getting you airscrew dead on, the needle will stay in the stock position,"which should be mid-clip" this comes from a guy who has done a bunch of carbs on 2 strokes and has never burnt a piston, or seized a cylinder.[8D]
 

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Ya you really need to know what your doing to fool around with the needle.
 

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Well guys...basically the needle controls midrange mixture. The pilot jet takes care of idle-off idle and the main jet controls wide open throttle because the needle is fully removed from the main jet. I'm not sure how to explain it other than the needle changes the mixture of the midrange because of how far in or out the needle is. Hope this helps a little bit, and doesnt confuse anyone.
 

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oh yeah...if you go to a bigger engine you will need to get bigger jets...your cylinder is bigger so more air will enter the cylinder thus needing more fuel also.
 

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i know after going thru my 600 that is bored to a 648 the jets were actually smaller then the 600 mains.i upped them and and bought all different sizes so i can fine tune it while riding it.
 
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