Engine Trouble Engine won't start

Discussion in '2-Stroke Engines' started by medicaltape, May 14, 2016.

  1. medicaltape

    medicaltape New Member

    I've been trying to get a friend's 2 stroke motorized bike working. We don't really know much about it. I think it's an "80cc" one. It worked fine 6 months ago or so, but it's been sitting since then. I got the clutch cable and everything that appeared to be wrong fixed.

    For a while, gas didn't seem to be entering the cylinder. I completely disassembled the... throttle body? whatever you call the whole assembly just past the carb and before the engine block, then put it back together. And it's dumping fuel in correctly now. It still wouldn't start, so I got a new spark plug (autolite 425, basically matches the one it was working fine on before), still doesn't start. Checked for spark, has a very nice spark, being new.

    The 2 halves of the block are bolted tight together, the exhaust and intake pipes are secured as well. I get it going down a hill, dump the clutch, and it makes plenty of noise (seems to mostly be coming from the carb) but 0 power and it doesn't appear to continue to run after I put the clutch back in.

    It's filled with fresh ~30:1 gas.

    I'm not sure where to go from here. I've basically had the entire engine disassembled and there's nothing obvious that's wrong with it. Ideas?

    edit: checked compression around the 2 halves of the engine (head gasket?) + spark plug and it seems excellent.
    Last edited: May 14, 2016

  2. Rob H

    Rob H Member

    I would prolly bet that being it sat so long you are lacking fuel to make certain give it a shot of ether or carb cleaner with air filter off and throttle wide open then try to start it.If it does try to pop off then you need to remove carb and remove needle and seat and clean the main jet.