2 stroke direction

Discussion in '2-Stroke Engines' started by r.bradley, Aug 30, 2010.

  1. r.bradley

    r.bradley New Member

    Hi guys,

    I don't want to sound stupid but is it possible to change the direction of rotation for a 2 stroke engine? The engine is from a 50cc pocket bike and will be using a friction drive kit from BMP. I'm just curious if its possible to do this as the engine needs to be mounted backwards on the kit, would it be possible to swap the clutch and flywheel to the opposite sides?

    Any help is much appreciated!



  2. GearNut

    GearNut Active Member

    Yes, a 2-stroke engine will be very happy running backwards. However I have never seen an engine case that will allow you to swap sides with the flywheel and clutch, namely because of the magneto mounts and the design of the crank shaft ends.
    The engine still can be ran backwards if you can figure out how to re mount the magneto in such a was as to have it timed to fire exactly at the right point in crankshaft rotation to run the engine backwards. Of course the pull starter would no longer work as it would now spin the engine the wrong way.
  3. r.bradley

    r.bradley New Member

    Cheers for that, do u think it'd be ok havin the cylinder head at the rear or should i add some sort of ducting to help with the cooling?
  4. GearNut

    GearNut Active Member

    You absolutely must have the fan shroud installed. The cylinder fins were designed to have the forced air flow cooling them. Without the shroud you will overheat the cylinder.
    You just got me thinking again, the vanes or blades on the flywheel are designed to push the air with the flywheel spinning in one direction only. They will still push the air by spinning backwards, but just be sure that they are pushing enough air to keep the cylinder cool.
  5. r.bradley

    r.bradley New Member

    yeh thats a good point, I forgot about the existing shroud. The pull start casing covers all the way up to the side of the cylinder for the flywheel vanes to provide cooling.
    Cheers for your help!
    Very Much appreciated!