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Post by JerryScript on Feb 21, 2015 14:50:26 GMT -5
lain. Raising the needle leans the carb before the main jet kicks in. Try raising it one notch to see if the bogging at take off reduces. After raising it you may have to richen the fuel mixture screw a dat to balance the idel. But just a little. wouldn't raising it open up the jet a bit and allow fuel in earlier making it rich? Raising the needle does make it rich when the main jet comes into play, the a/f screw affects things all the time. To be sure we are using the same terms, raising the needle means lowering the clip on it, or adding washers as spacers to make it higher. This allows fuel to begin to come out of the main jet sooner. |
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Post by JoeyBee on Feb 21, 2015 15:32:56 GMT -5
This is the guide I go by. I have seen it posted on this forum several times. I guess it would have been accurate to say raise the c-clip which lowers the needle and leans the mixture.  |
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Post by jerseyboy on Feb 21, 2015 16:27:57 GMT -5
If he needs more fuel at take off he can try raising the needle,LOWERING THE CLIP.
Not sure if it will help any though,,since its in the main jet circuit...it may,,cant hurt to try.
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Post by JerryScript on Feb 21, 2015 16:35:04 GMT -5
It's all about how you twist the throttle at take off. If you only open it 1/4-1/2, then the main jet will not come into play unless your RPMs are winding real high due to your CVT tuning. If you go WOT at take off, and your engine RPMs go high, then it also comes into play early. This is the way many people treat these low power scooters in an attempt to maintain traffic speeds, no one wants cars honking at them!
If you have a powerful engine (BBKd) that doesn't require more than 1/4-1/2 throttle at take off with your CVT tuned for normal RPMs (not raising above 4-5k till you get above 20mph), then your needle/jet tuning will be different from most scooters.
Tuning a scooter requires balancing everything out. The CVT will affect your RPMs more than anything else, and that will determine how you tune your carb.
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Post by JoeyBee on Feb 21, 2015 16:35:13 GMT -5
If he needs more fuel at take off he can try raising the needle,LOWERING THE CLIP. Not sure if it will help any though,,since its in the main jet circuit...it may,,cant hurt to try. From his original post it sounds like he is running too rich when he first accelerates. Raising the c-clip will lean the mixture out a little till higher RPMs and the main jet takes over. |
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Post by lain on Feb 21, 2015 19:07:53 GMT -5
I Think I recall my needle being all the way at the leanest space when I first took apart the carb when I got it. I'll take a look when it isn't snowing out lol
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Post by rcq92130 on Feb 21, 2015 19:59:34 GMT -5
I Think I recall my needle being all the way at the leanest space when I first took apart the carb when I got it. I'll take a look when it isn't snowing out lol you mean in July? |
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Post by lain on Feb 22, 2015 11:46:40 GMT -5
I raised the needle (lowered the clip) one notch. It seems a little better, but not much. It happens more when I have it on the stand than when under load, if that means anything. However that was how it was before I moved the clip as well, just not as bad right now. It feels like it is starving on either air or fuel right when the throttle just starts to be pulled, like lets say 1% throttle, it will sputter and slow down a lot, then if I add just a tiny bit more throttle, lets say about 10% throttle it stops bogging and speeds up.
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Post by JoeyBee on Feb 22, 2015 12:17:41 GMT -5
lain, Have you pulled the plug yet to see how you are running?
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Post by lain on Feb 22, 2015 12:54:36 GMT -5
lain, Have you pulled the plug yet to see how you are running? I posted my previous post before taking it ont he road. Just took it on the road and it ran so much better than before! I got much better speeds, and the bogging only happened when I was trying to get myself out of my back yard going like 5% throttle cuz it's all ice. It does seem to sort of bog down when I stop like I have to rev it very lightly a couple times to get it from stalling out. The idle is sort of high but I think it is because I have not turned it down and last time I rode was like 10 degrees, now it's a burning 40 degrees!!! lol |
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Post by JoeyBee on Feb 22, 2015 13:02:02 GMT -5
That's good to hear.
Ride Safe
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Post by jerseyboy on Feb 22, 2015 17:56:13 GMT -5
Yup 40 today zero tomoro...lol
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Post by JerryScript on Feb 22, 2015 18:14:38 GMT -5
I would suggest you continue to raise the needle until it makes it worse, then go back one notch.
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Post by lain on Feb 22, 2015 22:23:40 GMT -5
I would suggest you continue to raise the needle until it makes it worse, then go back one notch. Well, I was wrong about the needle on my carb being in the most lean position. It was on the 3rd of 5 notches. So there is only one more notch to go before it is in the most rich position. It is easy to fool around with the needle position tho on the keihin carb, I can just opent he seat, remove all my luggage (tools mostly) and unscrew the top of the carb to get to the needle. The circlip was sort of hard to figure out how to remove, I thought I was going to break it but I ended figuring it out, I just pulled it off from the end that was opposite the opening. I still feel like the top end could use a little more juice, so I will fool around with jets next "good" day... lol next week or so looks pretty much like negatives to just under freezing. |
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Post by jerseyboy on Feb 26, 2015 14:09:00 GMT -5
Yup,,needle nose to pull the clip off,,same tool to push it back on..let us know how it takes the fuel after you upjet.
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