KDXRIDER.NET

My stator setup lost a magnet so I've sourced a replacement magnet and put it in the stator/magneto. Do I need to balance it? And where in the world would I take it ? Called local shop and they don't even have a clue.


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Sorry being blonde!! I need to have the 'flywheel' balanced. Actually. That's my question...do I need to?!


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I would think it does need to be balanced, otherwise it creats uneven forces on the shaft.
Make a cone to put in its center hole and connect a string there. Supporting it by the string should show an imbalance by its leaning to one side. The low side is the heavy side.

I bet drilling a hole through a small solid rubber ball would work too.

Awesome! Hadn't thought of that method. Wicked! Thanks guys!


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Keep in mind that the balance of a single cylinder engine like the KDX is always a compromise. You balance for all of the rotating weight plus a certain percentage of the reciprocating weight. That might be 40% or 60% or whatever actually works best. What you're trying to shoot for is the least amount of vibration at a target RPM.

What this means is, IMO, small changes in weights will probably not be meaningful. For the flywheel, if it were me, I would rig up a mandrel shaft to mount the wheel on, the FW centered on the shaft and placed on a pair of perfectly level parallel straight knife edges. Decrease weight from the heavy side or add weight to the light side. You'll never get it dead nuts perfect, so shoot for a tolerance, say 40 grains or so. A .22 RF bullet weighs 40 grains. Put a rubber band around the wheel OD and add the tolerance weight to the light side. If that weight causes it to be the heavy side, you're in tolerance within 40 grains. I static balance pump impellers like this all the time.

Now, if the engine has a separate balancer shaft with bob weights, well that's another kettle of fish and something I don't know anything about.

Are you aware of re-slotting the stator plate and using a newer model flywheel?

Same sized magnet? in the same place? got to be good to go?