must read even for pros. By brndnpnt (Read 1,057 times)

[brndnpnt]

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They may remember the problem I had and its been some time now since I have been on this site so I thought I would post an answer to a very hard to diagnose problem.

If you have tryed everything there is to try and your scooter is still not running correctly meaning dieing chugging and not holding speed the problem is that your carb needle guide is warn out to ware the needle keeps jumping out the whole.

Thanks to fx in new Orleans I was able to get this fixed

15,000 miles and still rocking

[Alleyoop]

Brndnpnt,
Hey, good to hear from you bud, been a long time since I seen you long on. WOW!! the actual needle guide WORN OUT!!! Dang that is a new one on me, well never to old to learn as they say.
Thank you for letting us know what the HEY was wrong all this time. Never in a million years would I have even thought of that. Alleyoop

I guess that is why on some carbs the Guide actuall sticks out into the Venturi so even if the Needle goes up as high as it can it will not come out of the hole.

[Cruiser]

That certainly is an unusual happening. I have trouble visualizing this because I thought that the needle is always inside the passageway which leads to the main jet from idle to full throttle. I don't see how anything being worn would cause the needle to raise up high enough to come out of this passageway. I would think once the needle came out, it would get jammed. I could see something happening inside the diaphragm/piston which might allow the needle to come out of the main jet passageway, but that would not be a worn component? Is there some kind of guide built into the main jet passageway which could wear out? Most diagrams only show the passageway. Let's see what the "pros" think about this.

[zugzug]

Well I have had numerous old high mileage UJM's and several had carbs that had excessive wear and were not servicable or rebuildable. I even had one that did just as you described. The needle would slip out of the slot and jam open. So it wouldn't surprise me that a china scoot with 15k would have a simular issue. At least the scoot carb is fairly cheap. Try and find a set of decent rebuildable carbs for an old Honda CB.

[Cruiser]

The more common problem is wear on the needle and needle jet. Needles are easy to replace, but on some carbs the needle jet is not replaceable. Like you said, Zug, at least we have plentiful and inexpensive carbs for our China girls.

[Alleyoop]

EM,
HAHAHA!! that is because it was made on a FRIDAY WHEN THE EAGLE FLYS
Alleyoop