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pilot/air/idle mixture screw

22954 Views 25 Replies 8 Participants Last post by  frog13
I want to try to clarify this. When adjusting the pilot screw, turning it clockwise will lean out the mixture. So turning it counter-clockwise will richen the mixture allowing more fuel to enter the cylinder. So if there is a surge at low speed when opening the throttle quickly it needs to be leaner. Correct?

And is there a sweet spot where it will be easy to start and not surge or is it a trade off?
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I have done this and i'm thinking that maybe I need to remove a washer or 2 from my needle. The issue occurs when I rev up let off and then immediately rev it back up. There is a small hesitation which makes it hard to pop the front end up over obstacles.
Hmmm I took out 1 then 2 washers and the low throttle miss is fixed but now I have it at mid/high range and when I rev it all the way out, it smokes a little

I now have it set with a 130 main, 3 .01 shims and 2.5 turns out on the pilot screw. It was at 130, 5 and 2.75 turns out. And i'm usually running at about 475ft above sea level.
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I am about to head out to the garage to mess with it some more. Any suggestions?
I am an eternal optimist and take anything that may be seen as critical, as another suggestion/opinion that should be considered.

Yes. The bike was running fine when stock. It was popping under decel (lean) so I opened the pilot to 2.5 and it ran fine but I feel it is better to run a little rich through the whole throttle range especially since I do a lot of sustained wot. I went back to 5 washers today and ran it for a while with minimal problems. I will pick up a new plug on monday to see if that helps. Any suggestions for a better plug than ngk? Or should I stick with them?
Put in a new plug today. No change... Did a plug chop and it was white but I ran it through all the ranges so i'm not sure where it is running lean. So I guess I am going to undo everything i've done and start over. Back to the 126 main and no shims and try this again.
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I ride single track trails with lots of twistys and whoops so a responsive throttle is a must.
When drilling the slide, is it the hole right next to the needle that is drilled out? I'm not sure that I will be going that route but I am curious.
I removed the shims so now its at 130 main and 2.5 turns out on the pilot screw. Seems to be running well through all the ranges. I will now try it with one then two shims and see what effect that has on it. If it surges with both combos, I will just stick with the 130 main only.
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