You could use the RB aluminum end housings to get a 110 pound 2 rotor
long block. With 250 HP the thing will climb like a jet. Just
watch the
Vne. Only problem is the RB end housings are about 15K. What is the
expense of building a one rotor that is still somewhat
experimental even
compared to the 2 rotor, and you do not have the vibration problem
Richard described.

Dale Davies

Dale, the 750 is only rated for 140 hp by the designer. Also, a
250 hp
engine would exclude the craft from the light sport category, a
major
reason for the popularity of the design, no medical required and
easier to get the light sport ticket.
The Zenith CH-801 would be the choice if light sport isn't a
criteria.
C. Smith



    There is no limit on engine power for an aircraft to be eligible as
    light sport. If you can make a two-rotor engine with cooling and
    propeller reduction unit under 200 pounds, I say go for it. The only
    power limit for light sport is that the completed aircraft can't
exceed
    120 kt at full power at sea level. You can assure this with proper
    choice of carburetor or EFI.

    David Josephson



    A pitot tube sensing air speed and applying the pressure to a
diaphragm to close a butterfly down stream of the carb or EFI would be
able to limit speed to the 120 kt required. Takeoff would be a blast.

    Dale Davies

The 750 & 750 cruZer is rated 100 - 160hp max 280lb installed.... the
LSA in Australia doesn't have the 120kt max limit.. but the VNE is about
138mph for the cruzer. I  have ordered a cruzer kit should be shipped
any day now.... And will be going the 2 rotor all alloy route, providing
the i can keep the installed weight under 280lbs...
Keith Bennett