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Carb piston thingy stuck

Discussion in 'Technical and Troubleshooting Torque' started by mrp, Aug 11, 2007.

  1. That small piston looking thing you can see through the top of the carbs is stuck on 1 of my cylinders. It opens by itself but then won't close. It doesn't have anything physically blocking it and I've swapped around the springs and rubber to see if it made a difference but nope. I'm guessing all this does is stuff up the air mix in that cylinder since it's always open.

    Anyone encountered this problem and can gimme some advice? None of the parts seem damaged or worn either.

  2. Something must be worn or damaged.

    Check that the carb slide diaphram is seated properly under the cover, and that it has no tears etc. They must be seated tightly in the groove around teh carb top.

    If the slide isn't returning with the spring pressure, it may be binding on something, not good.

    This will mean the cylinder is running too rich, with poor performance.
  3. With the terminology you have used, your best bet is to box it up and send it away for reconditioning.

    Regards, Andrew.
  4. Yep as above.

    It might be an idea to start looking for a new set of carbs.
  5. Oh, and these guys aren;t the cheapest, but many, many people I know have used them with great results, just get them back, drop the carbs on an engine and go.

    Regards, Andrew.
  6. Reconditioning? :? Can't you just buy a new piston, diaphram, spring etc? It's not a hard part to get to or fiddle around with so it would be easy.
    and typhoon you don't need to assume I don't know shit just because I was in a bit of a rush :)
    ok maybe I don't know shit but I'm learning :p
  7. are you talking about the carb slide? and how do know it will open by itself? ie when opening the throttle. maybe crap has built up in the slide seats, just needs a clean out. i couldnt imagine why it would just stick other than that if nothings broken, unless the needle is bent?

  8. Well, if you know shit, just get new parts and don't bother us! :LOL:

    Regards, Andrew.
  9. Yeah the carb slide, I can see it go out when I rev it (airbox of) but it doesn't come back in. Bent needle sounds possible, I will prolly find something next time I get in there and wonder how I missed it last time :oops:
  10. Carbs are pretty simple things really, there must be a logical reason that the slide is getting stuck.

    Since you've already tried another spring and diaphram, put a different slide in there and see if it still gets stuck. If it returns freely, then there's something wrong with the original slide/needle.

    If the needle is bent, don't be tempted to buy second hand ones, it might just add to your troubles later down the track.

    Return all of the settings to standard (including balance!) and you should be sorted!