Much as I hate to say it, you will probably be better off with a more common UL motor for this one.
Thanks to everyone for the info. Looks like you're probably right about the 2-stroke for the Airbike, probably a 503.
Cheers,
Rusty (Airbike wing kit materials shipped today)
I concur. I've been looking for a good replacement for my 503 (Kolb Twinstar) for years. When it flys again, it will probably be with the 503 that has powered it for 800 hours.
Tracy