If that's true, then I wonder why there is no interest in them? These would seem to make an excellent conversion engine since they are:

1) Cheap
2) Powerful (supposedly)
3) Parts readily avialable

They are knock-offs of the Zenoah G230RC/G260RC car engines, with at least some level of parts interchangability. What's the difference between a G230RC and a G23 aircraft engine?

The Sikk / Superior engines are available in displacements of 23cc, 26cc, 27cc, and 29cc versions available. The 27cc and 29cc engines appear to be bored or stroked versions of their G230RC and G260RC clones.
The scooter/goped market is very competitive with everyone trying to squeeze maximum power from these engines for racing. You can buy these motors with racing pistons, cylinder decking (increased compression), porting, and matching already done for a small extra cost. The other nice thing is that some of the places selling these engines will delete the engine covers, exhaust, etc and reduce the price accordingly.

For example, at [link=http://www.hookupzracing.com]hookupz[/link] racing, you can get the 27cc engine minus the engine covers and muffler for $135. That's not much more than what some folks are paying for refurbished chainsaws. I'm really tempted to get one of these, but am wondering if anyone else has had any experiences with them before I order it.