I would suggest you put it in the public domain where everyone can benefit from your design. You developed it in 2008 and it hasn't earned you a return for your investment, so why not publish it for everyone to benefit. Keeping the idea to yourself hasn't and will not earn a return on your investment. There are a lot of people that have spent money on their ideas and shared with others and not have received a dime for their efforts. We all have benefited from other peoples ideas. I am willing to share with others because this is a hobby and like being a contributing member to this community. I don't expect a monetary return on my ideas, just a satisfaction that someone uses my ideas for their enjoyment.
Join the Christmas spirit and give a gift to the motored bikes community.
Happy Holidays!!!
Chris
AKA: BigBlue