Skipper Project: Power Loss From Carb?

Discussion in 'General Tuning' started by macka, May 15, 2016.

  1. macka

    macka New Member

    Messages:
    16
    My Skipper 125 is in bad shape! In the next few days I'm due to replace the variator/rollers, but there seems to be a power loss problem that is noticeable from carb adjustment. As it stands the carb was on the bike when it done 60mph, now I'm lucky if it does 40mph...

    When the bike is started up and before the choke, it struggles to tick over, as if the idle screw is set too low. After the choke, it lacks any kind of power from the back wheel. Hills are a no-go and slight inclines need a run up!

    Now the other day whilst doing a running test, I blocked the carb overflow pipe with my finger and the rev's rocketed up!? I took the bike out for a spin with the pipe taped up and the difference in torque from the back wheel was immense?! I even conquered the local hill at 30+ mph without a run-up!!!

    That being said... Whilst the pipe is taped, there is slight-moderate bogging when the throttle is fractionally opened up, as if the mix is too rich. And the rev's are that high that bike just wants to take off from under you, as if the idle screw is set sky high.

    I know little about this stuff but it sounds like "the engine is loosing pressure through the carb".
     
    Last edited: May 15, 2016
  2. Stevep

    Stevep Well-Known Member

    Messages:
    5,895
    Too much air flow through the carb. Check the air mix screw is not too far out. Should be about 2 turns out from fully home. Also check where the clip is on the slide needle. Put it on the middle slot if isn't already there. Hows the air filter? If it's an open or racing one then it could also be allowing too much air through.
     
  3. macka

    macka New Member

    Messages:
    16
    Cheers for the fast reply Ste!

    Had a feeling it was too much air so removed tape to re-open pipe, then gradually blocked off air filter intake. Was expecting the same high-rev's, but it bogged down and cut out? The mix screw is currently set at 2-out as the idle screw is temporarily seized in place. Carb is a "CV" carb. It doesn't have a clip for needle adjustment, see below. Air filter (after-market stock) seems fine, sponge could probably do with being re-cut as is a bit short on a few edges.

    [​IMG]
     

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