Zip 50 2 stroke post rebuild - not running

Discussion in 'The Workshop' started by Glu, Oct 10, 2020.

  1. Glu

    Glu New Member

    Messages:
    2
    Hi Guys and Gals

    My sons Zip 50 2 stroke big end bearings failed. So I stripped it, bought and fitted new crank, piston, rings, seals, oils pump, oil pump belt, honed the barrel and used new gaskets. Checked reeds, all good. I striped carb and cleaned with card cleaning spray, all looked fine, and it was running before rebuild. It has an almost new exhaust .....

    I bled oil pump, checked spark, And tried a start. It needed a spry of engine start, but it started, but ran terrible, no throttle control hardly, but would start on fuel only, so I ran to try and settle it, but it popped a little, more of a fart than a back fire.... so I thought ignition timing, but it looks fixed. Then it stopped even starting. Humm, crank seals? Poor compression?

    Well I get 100 to 125psi cold on compression and crank case, from carb inlet to end of exhaust pipe holds 6psi, losing only 1psi in an hour, and I have tiny leak in exhaust bung I fitted.

    Can not up load pictures of gages it set up, but is from Dr YouTube and it all seems good, if anyone can tell me what I can check further please share.
     
  2. Glu

    Glu New Member

    Messages:
    2
    Tried that after you suggested. Same. But, a bike
    Mechanic friend asked if the needle in card has the hold down clip. It did not so you needle was floating. Made a clip, so that is fixed but same.

    Looking at magnito fly wheel I can not see the woodruff key, and I know you could when I took it off so maybe it got pushed out when I rebuilt it and now timing is out .... maybe .... now I need a puller, (used a hammer to get old crank out), so back onto online shop ..... will a 24mm 27mm puller be the right one?
     

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