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Login to post Forums » Sprockets » Has anyone motorized a bicycle?

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March 13, 2009 3:39 p.m. ClemSparks UberDork

Hey all,

I got this heavy, off-brand, old, single speed bicycle a while back. I was about ready to just give it away or recycle it when I got my old Puch moped running and though about how it might be cool to paint it up and put an engine on it. I remember seeing kits available to put a two-stroke gas engine on a bike, and thought I'd check here to see if anyone had done it.

I suppose eBay would be my friend.

Anything to consider? should I just buy my own engine and go to town (I have access to a mig welder and should have the basic fabricaton tools already).

Like I mentioned...has anyone done one? Or maybe researched it yourself and can give pointers?

Thanks, Clem
March 13, 2009 3:59 p.m. ManofFewWords Reader

Saw this one just the other day http://burlington.craigslist.org/bik/1054742134.html
March 13, 2009 4:03 p.m. Woody Dork

I'm the original owner of this bad boy:

It's a Sears badged Tanaka from the late 70's or early 80's.

Takaka site: http://www.users.globalnet.co.uk/~pattle/nacc/arc0394.htm

Forum: http://www.motoredbikes.com/index.php?s=dddfefe4432435583034ffbe26bcc8c2

Like everything else, someday when I get some time.....
March 13, 2009 4:06 p.m. ManofFewWords Reader

I think I remember those (I'm 39). Now that I look at it though, it looks like this has weedwacker DNA...hmmm...
March 14, 2009 5:29 p.m. alex Reader

I have a friend that stuck a Chinese copy of a horizontal Honda motor into a road bike. He bought the kit on eBay.

That's all I know.

So, to answer your question: yes!
March 14, 2009 6:20 p.m. rustyvw HalfDork

I've been wanting to get one of these for a while.
http://cgi.ebay.com/NEW-70CC-GAS-MOTORIZED-BICYCLE-ENGINE-KIT-MOTOR-SCOOTER_W0QQit...
March 15, 2009 12:00 p.m. alex Reader

Hell, maybe that's the kit. I thought it was a Lifan copy of a Honda motor, since those things seem to get put in 7/8ths of the vehicles exported from China, but I could be wrong.
March 15, 2009 12:10 p.m. 4cylndrfury Reader

grainy video, but its pretty awesome...hoffman bikes Circa 1993 or so. Motor shows up around 1:05...

http://www.youtube.com/watch?v=KU61QrH8hkU
March 15, 2009 1:43 p.m. thatsnowinnebago HalfDork

I do have an old roadbike I converted to a single speed but I've been thinking more and more about sticking a motor on it. This is a good/bad thread for me now.
March 15, 2009 3:24 p.m. jwdmotorsports Reader

This has really got me debating building one. There are some pretty cool ones online.

A motor on one of these would be cool. http://cgi.ebay.com/BIKE-CHOPPER-BICYCLE-CRUISER-TOY-ANYONE-8-T0-80-YRS-OLD_W0QQit...
March 16, 2009 9:31 a.m. Autolex Reader

rustyvw wrote:

I've been wanting to get one of these for a while.
http://cgi.ebay.com/NEW-70CC-GAS-MOTORIZED-BICYCLE-ENGINE-KIT-MOTOR-SCOOTER_W0QQit...

I have one of those on an old road bike, it does a GPS Verified 27 miles an hour. The whole Rolling start thing is kind of a pain, but it is fun to ride.
March 16, 2009 4:34 p.m. Jensenman MegaDork

My dad wanted one of these when he was a kid.

Actually, he wanted one of each. http://www.whizzermotorbike.com/History.html He said a buddy had one; notice how the belt pulley is attached to the rear spokes? He said that thing was always breaking spokes, to the point whre the guy just kept a couple of extra rear wheels and would move the pulley to a spare when the rear wheel got too bad to use.
March 16, 2009 6:04 p.m. CLynn85 New Reader

I just ordered one of the kits from http://www.thatsdax.com/ , the old style not the titan one. Can't wait to install and try it out. I figured it should make for some neighborhood fun, occasional jaunts around town, and a great cruiser between the rental houses at OBX. They're a little more expensive than the ebay link, but from what I've read have top notch customer service.
March 16, 2009 6:19 p.m. neon4891 SuperDork

rustyvw wrote:

I've been wanting to get one of these for a while.
http://cgi.ebay.com/NEW-70CC-GAS-MOTORIZED-BICYCLE-ENGINE-KIT-MOTOR-SCOOTER_W0QQit...

Soooo tempting
March 17, 2009 6:29 a.m. jwdmotorsports Reader

I've been sucked in to the motored bike idea.

I bought one of the bikes I posted a link to above and an 80cc kit off of ebay. I'll post some pictures after I get everything in and assembled.
March 18, 2009 3:01 p.m. ClemSparks UberDork

I was looking at some of the different kits on ebay and such.

I'm curious how the right-side sprocket (engine driven one) attaches to the rear wheel.

I don't like the muffler just hanging out there ponting down the way they seem to. It seems like that might be able to be fixed with a little fabrication to route the exhaust where I wanted it (though I'm not sure what sort of effect that might have on engine tune...it doesn't look like a tuned pipe anyway).

The mounting braket looks like a "universal" compromise...I'm curious how well they bolt to the bike.

There's my observations based on what I've seen from the photos of the kits online...

Clem
March 18, 2009 7:21 p.m. CLynn85 New Reader

Clem,

From my research before I bought my kit I might be able to provide a little insight.

The drive sprocket mounts on the left side of the bike, and is actually mounted against the outside of the hub, but retained via a backing plate on the INSIDE of the spokes, with rubber shims providing the spacing/gripping the spokes. Hope you chose a bike with good spokes....

The muffler is in a pretty standard location, but you can bend the pipe to make it "hug" the frame more, and I've seen several people who have rerouted it up and out the back instead.

The brackets are definitely pretty universal, using either steel bands, clamps, or u-bolts to attach to the frame wherever convenient. The chain tensioner is a similar affair.

I'll likely do a quick install on an older bike to see how I like it before I go out and build a "proper" bike with welded in mounts, spring tensioner, maybe some better styling, etc.

Hope that helps.

Carl
March 26, 2009 9:57 p.m. CLynn85 New Reader

Just a little update. I assembled my bike last weekend. Got it together and running. Still needs some tweaking, and replacing some of the hokey spacers and crappy brackets, but it's functional as is. Very fun to ride and in the half hour I rode it around the neighborhood and area I keep getting stopped and asked tons of questions about it.

I pulled the old huffy out of the barn in the morning, hosed it off, put a new tube in the rear tire, and had a running motorbike by evening.
March 27, 2009 7:13 a.m. fastEddie Dork

Cool! The tanks shape fits well with the frame design, almost looks factory!

Nice 'Stang too.
March 27, 2009 12:26 p.m. ClemSparks UberDork

I'm impressed! Thanks for the photos.

I've got a similar bike laying around that would be perfect for this (like I mentioned above).

Question: does this have only a cable operated clutch without a centrifugal one. Or is it like my moped and has cable clutch (pull lever to ENGAGE clutch...for starting) and a centrifugal clutch.

I already see a cottage aftermarket for upgrade parts for these kits. Think: better rear sprocket, tuned pipes, etc ;).

Clem
March 27, 2009 4:35 p.m. CLynn85 New Reader

It's cable only, although there is a centrifugal clutch avail for some of the motors, as well as a pull start. There's a little aftermarket, but not a huge one

I was hoping to get some miles on it today and break it in some more but weatherman was wrong....again....
March 27, 2009 4:36 p.m. CLynn85 New Reader

Oh and just to show the creativity of some of the enthusiasts check out this build:

http://motorbicycling.com/f15/iride-customs-boardtrack-bike-1610.html

I'd like to do something similar in the not so distant future with one of these little motors.
March 27, 2009 4:54 p.m. 16vCorey SuperDork

What's the gear ratio and what kind of RPMs does that engine turn? I've been accumulating parts to do a very similar set up, but with a chainsaw engine, and I'm not sure about the gearing.
March 29, 2009 4:46 p.m. thatsnowinnebago HalfDork

I wonder how easy it would be to get one of those little motors to make more power. Have you taken the head off CLynne85? I wonder if the ports are decently shaped or if a dremel could help them out some
March 29, 2009 9:59 p.m. CLynn85 New Reader

I'll have to count the teeth on it, I know the rear sprocket is a 44t and I think the front is somewhere in the 10-12t range. Not sure how many revs it's turning, haven't put a tach on it.

I'm sure you could probably build them a little, everything is basic and not a whole lot of post-process machining. I'm sure you can probably clean up the ports a little, I've also heard that the stock head gasket on some motors is REALLY thick and you can drop several thousandths off the gasket and increase compression, there's also a high-comp. head available as well.

That being said, they're still cheap made in china motors, and I'd be hesitant to try and wring them out too much. I'd like to do another build that's more performance oriented, so that may be a good time to try some quick and easy mods, but for this little huffy, it's fine just the way it is.

Oh, and just a side note, even though I'm still running a 20:1 mix for the first couple tanks I did get it up to 28 on flat ground today according to the cheapo bike-puter.

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