Nah 2+ HP is plenty for a bike. The only issue lots of motorized bikes have is the lack of gearing. If high end sports cars had only one gear I bet a happytime kit could beat it off the line since you could at least peddle. I think lots of the early racing motorcycles had not too much more displacement than our little engines but they could really haul arse because they had many gears.If only someone could pattent a 200cc engine so it fits into a 50cc bicycle frame,now that's something....i'de buy it.
Now that looks really useful. As you say it could be a really ideal family car replacement. A good social way for 4 friends to go on a cycle touring trip together too.Back to the topic I saw this 4 person 49cc 4 wheel "bike" on the staton website http://www.staton-inc.com/Details.asp?ProductID=2443
It would be really tempting to get if I had somebody else who would want to ride it with me. Looks like it has a lot of potential with the right owner and its really cheap for whats essentially a car replacement. I wonder how much the cops would tweak out about it though...