What engine do I have here?

Discussion in '2-Stroke Engines' started by bossman, Mar 6, 2011.

  1. bossman

    bossman New Member

    Hi all, first post.
    I got the bug for a motorized bike after seeing a neat bike around town so I did a search and found this board, thus the journey begins.
    I have a nice mountain bike and I bought a little chinese made minibike from a yard sale a year or so ago for $15, the owner said it didnt run and it needed a few parts, I tinkered with it for a couple of hours and the motor runs great!
    I have removed the engine from the bike and have it mounted in my vice for some cleaning and inspection.
    It is a two stroke, unknown displacement ( i`m thinking 36cc?) it has a gear reduction transmission, a centrifugal clutch and it is electric start + pull start.
    heres the pix:
    [​IMG]
    the donor minibike

    [​IMG]

    [​IMG]

    [​IMG]

    I connected a 12v alarm system sealed lead acid battery and it turned over very well, the carburetor throttle plate is cracked so it will not travel througout it`s entire range, the parts seem cheap enough but I need to identify the brand and model so I can order parts.

    if this engine is 36cc will it be powerful enough to run my mountainbike with my 190lb. butt on it? or should I go for a 50cc, I live in Florida so I gather that 50cc is my max size limit.
    Thanks in advance for any information.
    Scott
     

  2. ibdennyak

    ibdennyak Guest

    That little minibike is cute in a perverse sort of way. Engine definitely looks chinese clonesy. Odd how the PTO is off the fan side...and looks like into a standard 5-1 pocket bike transmission. I'm guessing the other side has the starter which would be similar to a Mitsubishi clone with electric start. That engine is similar to the HF 52cc people are using. Unfortunately, I have no idea of the manufacturer of your engine. I will say that if the carb is the only problem, a diaphragm carb from a similarly sized engine would probably work. Might try some of the brick and mortar stores that sell scooters and pocket bikes for a few hints. Sorry
     
  3. bossman

    bossman New Member

    Theres a shop called "dirt cheap fun" near by that sells pocket bikes etc. I`ll check them out.
     
  4. bossman

    bossman New Member

    Success!
    I took a zama carb off my ryobi weedeater and it bolted right up, problem was the bore of the zama was larger than the bore of the original carb and intake manifold.
    I put the intake on my drill press and bored it out to match the carbs inside dia.
    The engine ran well for a few moments but bogged under WOT after a few moments.
    The choke system on the zama is the type that richens the mixture rather than a butterfly that restricts airflow, I noticed that after warming up if I switched the choke on the engine would run well at WOT and not bog, so I surmised that the mixture was lean, a spark plug check revealed the telltale sign of a lean burn (white ceramic, very dry), The mixture adjustments on the zama are pre-set and require a factory tool that is not readily available. I searched the net and found a youtube video where a young man describes how to use a dremel cut-off wheel to cut a slot in the screws so a small screwdriver can be used.
    I started the engine, let it warm up and slowly began to richen the mixture as I throttled the engine up and down, soon I found the setting that would allow the engine to run wide open, I mean REALLY wide open, it was scary to some extent how fast this engine will spin. I richened the slow speed setting slightly and now the engine transitions from idle to WOT very smoothly without any stumbles or misses.
    Now for an expansion chamber.......
     
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