Instructables
This is the motorized bike I built today. Hope you like it!

It started with a 26" Avigo Ridgedale Mens cruiser. Brakes are coaster style, but I'm going to add front disc brakes soon. I fitted on a 66cc Skyhawk bike engine. Runs up to around 30 mph. Gets 140ish miles per gallon. Very comfortable to ride on. Whole thing cost me about $270 US, and about 2.5 hours.
Purrs like a kitten and hauls some serious a$$.

One word. Awesome.

Update: Okay so since the stock CNS carburetor was giving me trouble I decided to buy an RT carburetor. I've seen nothing but good reviews on it so I will report back when it arrives.

Update 2: My RT carburetor arrived today. I am shocked at the increase in power, speed, and throttle response. This carb is at least 100x better than either the NT or CNS. If you own one of these bikes, get one. www.thatsdax.com It also looks a lot better and seems to be much higher quality. I am not disappointed, thank you Duane.

Update 3: So I've ran it for a good 60 miles now and it's still going strong. I purchased a 36 tooth rear sprocket for some added speed, albeit at the cost of hill climbing ability. That's alright though, my area isn't particularly hilly, and if I come across one, I can just pedal assist. With the sprocket, my top speed jumped to 39 mph, and my cruising speed went from 25 to 30 mph. This means I can now comfortably keep up with traffic in the city. Sweet.
cbecker30110 months ago
could you post the link to the RT carburetor please? thanks :) cool project though!
I made a motor bike with the same engine and i found somthing called a boost bottle. After i put the boost bottle on it road alot smoother and it was alot faster i think you should get one of those if you want to improve your bike. It cose about 20$ on ebay
oskymike2 years ago
want one,but the laws in england are so stricked.
kbales oskymike2 years ago
lights and helmet and you are good to go.
http://www.motoredbikes.com/showthread.php?8970-Any-problems-with-the-Police-in-the-UK

Most areas don't have specific motrized bicycle laws, moped laws apply.
kbales2 years ago
I'v done a four bikes and used them on a 32 mile round trip commute.
Words of advice:
The stock chain tensioner (shown above) is a pile of headaches in itself. buy/build an upgrade.
the 2 hp power engine is enough to pull your rear wheel out of "true". Get either a hub adapter or at least a heavy duty rear wheel and 12 gauge spokes.
Also, maybe most important, the kit itself; do not get the cheapest kit out there (about $120) and don't get ripped off paying over $200 or $220.
The boygofast kit is cheap and has good accessories.
The Gru-bee is the best engine on the market and can be found in kits under 200.
Finally, these things require a lot ot adjustment and tinkering. carry a tool kit capable of rebuilding the whole thing by the side of the road.
dremeldude2 years ago
I was thinking about putting an engine on a road bike that I picked up off the side of the road for free, do you think this is possible?
LiquidLightning (author)  dremeldude2 years ago
Sure why not?

Just be sure everything is solid, not rusted out, that the wheels and bearings are all in good condition and very well greased. Won't regret it.

dag_293072 years ago
Hey Liquid, Welcome to our world. I have been a MB'er for about five years and I have 5 builds to date. I love your ape hangers, definitely gives the bike character. I would also like to extend an invitation to you to join us at www.motorbicycling.com
It is a forum created by those of us who love the motorized bicycle and want to help others that want to get started and to share our horror/success stories too.

I extend this invitation to you and anyone who just wants to research the world of the motorized bicycle.

Keep the rubber side down and hope to see you in the forum. ;)
LiquidLightning (author)  dag_293072 years ago
Lol I'm a bit late in replying, but I am already a member there. I'm frozenveinz. Been there for a bit of a while. Nice to see someone from the forums here.
dag_293072 years ago
sorry here's the link http://www.motorbicycling.com/index.php
thomasready2 years ago
I'm a disabled vet and would love for someone to make me one so I could bye it from them if you are interested please email me at thomasready@msn.com God bless great looking job I cant afford a car....Thom
l8nite3 years ago
a friend built one, really cool transportation but scary at speed, the spokes and bearings aren't built to take the added stress, upgrading to heavy duty wheels is cheaper than a week in the hospital with a busted arm and leg.. thank you for sharing
zazenergy3 years ago
wow this looks awesome! I would love to see a video of you on this. Have you considered doing a step by step instructable?
LiquidLightning (author)  zazenergy3 years ago
No need for an instructable, the manufacturer has a very nice step by step page with pictures. http://www.grubeeinc.com/USA/Skyhawk%20Instructions.html

And as for video, should that be POV or third person?
Seconded!!