Picture of Motorized Bicycle DIY: The hard way

Squishing a Honda GXH50 into a Huffy 24" boy's Cranbrook Cruiser Bicycle.

170 MPG - Really?

Short answer: NO - not for me, I drive full throttle almost all the time (30 mph), and I'm getting 110-130 mpg (depending on the wind)
Long answer: YES - if you're just going for a leisurely putt around town and aren't in a hurry - yes, it will get 170 MPG!

uh oh... the short answer was longer than the long answer... (sorry!)

The "Other" Answer?


OK, enough with all that!

We now return you to your original programming-in-progress...
(Sorry you were so rudely interrupted by this tacky updatey-thingy)


As of 2012, the Minnesota statutes have re-classified Motorized-Bicycles as MOPEDs and are
now required to be registered and plated. BUT!!! (and this is the part that makes me angry)
The DMV/DVS will NOT register "homemade" MOPEDs without a federally approved MSO (Manufacturer's Statement of Origin)
a.k.a. built in a federally recognized and registered factory.
Since *I* am the manufacturer, there is no way I can possibly do that.

I am currently pursuing registering it as a "Specially Constructed Vehicle" - lumped in with Choppers, Street-Rods, Reconstructions, and all other modified vehicles. These people want RECEIPTS!
When I started this project a year ago, it was a BICYCLE and I didn't bother keeping any receipts (who could have known?)
Do yourself a favor: SAVE ALL RECEIPTS!

OH NO!!! MORE UPDATES!!! (run away! run away!)

Update 2013/09/02:
I've added some recent pictures of her:

New "Tail-feathers" (she now has "running lights")
New buckboard (strangely attached)
New Collapse-able Saddle Basket (she's now a workhorse! - I can actually carry sh*t now!)

Update 2013/08/25:
The lighting circuitry is still a work-in-progress...

With the addition of 2x 1N4001 diodes in a "Y" configuration, the lights are now powered by the batteries while it's not moving (a.k.a. "stand lights")

AND, when it's moving, everything is now powered by the dynamo!

Also, it now has additional "running lights" and a re-designed (and removable) tail light assembly.
Updates to the circuit diagrams are forthcoming as well as new pictures - when I can find the time.
(it's been a busy summer!)

Update 2013/06/02:
After much frustration with the electrical system involving 2x 2.7v 82f "SuperCapacitors" in series, I have decided to dump them all together due to the fact that "THE LIGHTS DON'T COME ON UNTIL THE SUPERCAPACITORS ARE CHARGED".

I've done my best to find a way to overcome this problem, but hey: I'm not an EE.

(Driving 1+ miles in the dark until they charge is totally unacceptable)

The system is now split into:

1: The Headlight is exclusively powered by the Dynamo running through the rectified/regulated circuit.
1a. The voltage regulator has been changed to an LM7806 (+6vdc).
1b. The addition of a 1000mA BuckPuck current regulator.

2: The "Tail Lights" (one word: BATTERIES)
2a. The "Tail Lights" refer to every other light on the bike - and I want to be ABLE to light it up like a christmas tree!
2b. I hate batteries.
2c. Batteries DIE.

3: This thing has TWO POWER SOURCES (unacceptable!).

4: There has GOT to be a way to recharge batteries from the "other" source.
4a. I thought supercapacitors might be the answer...

5: HELP!

Older Update: The comment section contains the instructions for "getting it registered & plated"
Many thanks to all the people who have helped me in this quest.

/# end of updates. (whew!)

ANYWAY, as I was saying:

This bike project started out as a request from my wife:

She has a 4 mile hilly terrain commute to work (and she's very frugal)

We saw a youtube video of a motorized bicycle in action doing 30+ mph and getting 170 mpg.


She said: "Can you build one of those?"

I said: "Hell yes!"

Then she said: "Well then, go ahead and build one for me"


(For the record, I think I have just about the best wife on the planet)

The 1st picture was a current (September, 2012) view of our new "MOPED". *updates forthcoming

1: It's got all the "legal" stuff taken care of... (it's been inspected, registered, plated, and insured)
2: The seat has been repositioned just as low to the ground as possible.
3: The headlight and all of the electronics have been upgraded - (see the schematic).
4: The turn signal/brake/horn switches have been upgraded.
5: The brake lights and turn signals have been upgraded.
6: The fuel filter has been upgraded.
7: The air filter is in the process of being upgraded.

It's DONE, FINISHED, COMPLETED, etc, etc, etc...


I've come to the realization that: THIS IS A NEVER ENDING PROJECT !!!!!

(run away! run away!)


The 2nd (or is that the 10th?) picture is how it looked right out of the box around May, 2011 (*some assembly required)

The 3rd picture was a recent (March, 2012) view of how far it had come over the last year or so that I've been working on it.
- A very upgraded version from before the "long, cold, winter of 2011 - that never happened in Minnesota"

It has come a long way since then!

(updates to this site are forthcoming - REALLY!)
I just need to take more pictures, measurements, figure out a way to dis-mount the tail-light structure from the seat, add running-lights, and hopefully design a rear frame-cage that can support the new tail-lights and baskets or saddlebags.

The rest is, well: A (very) detailed log of my work in progress...

Buy the ticket, take the ride...

(I hope you enjoy the trip!)

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bogyman57 (author) 2 years ago


I went to the inspection site early this morning - armed with what I thought were the correct forms.

After waiting in line for 3 hours, I got the bike (oops, MOPED) inspected.


At least THIS guy knew what I needed to do:
Go BACK to the DMV;
Fill out a "Statement of Facts" form;
Apply for a TITLE;
Supply 4-view PICTURES;
PAY the tax.

I went back to the DMV - who needed to call their "help desk" (and I use that term very loosely)

The "help desk" guy told her that MOPEDs don't get registered/plated.

I showed her the documentation that I printed out from the DMV website that contradicted what she was just told.

She told that to the guy at the "help desk" what I had - so he had to go talk to his supervisor.

When he came back he said something like:  "Golly gee - I guess you do!"

Then she asked what the procedure was for doing that...

He had to go talk to his supervisor again.

It turned out that she had to do EXACTLY WHAT THE INSPECTOR SAID TO DO.

I walked out of there with a plate in my hands.

I'll be receiving a letter from the DMV letting me know when I can schedule an appointment to go BACK TO THE INSPECTOR to have HIM weld my new "V.I.N. PLATE" onto my bike (oops, MOPED).

Wotta nightmare!

At least my wife doesn't need to worry about getting pulled over now.
bogyman57 (author)  bogyman573 months ago

Good Gawd! Another Warning!

It seems that the "Low Oil Safety Shut-off" feature on a Honda GHX50 is ummm..


That's right folks... She seized up on me...

It let me start it - I got about 20 feet, then it died... I started it again: same thing.

I started it for a 3rd time, and it went fine for about 2 miles, Then it started to lose power until it killed again.

I peddled it to the nearest gas station to put oil in it, but it was too late, the pull-start felt REALLY stiff - bad, bad, bad!!!

In retrospect: (duh) I should have paid attention to it (duh) after the 1st kill... (duh)

She's gettin' a new engine in the spring.

yea gov't employees change the rules so much everyone that works in a gov't job are confused

(removed by author or community request)
bogyman57 (author)  jim.cambridge.734 months ago

Thanks for the input. But, the vast majority of this bike is finished. (a few tweeks are needed here & there). I'm not going to pay another $100+ to get the wheels re-built again, and replacing the frame with an upside down version won't do any good (have you looked at the pictures?) because an upside down frame would make it impossible to pedal.

the pedals would be welded to the front of frame behind the front wheel like a recumbent bike it may not work on yours unless the pedal crank tubing for the cranks are higher because your frame is shorter than this bike in photo below


hers what it would look like, the skinny tubing in rear of frame is bent up making the rear wheel lower and you can bend the front fork up and tap on and weld a identical fork to you fork to make it longer or buy new forks that are sold bent up which lowers the wheel like this bike in the photo,also to lower it is keep the 26 inch wheel in front and a 24 in rear or 24 in front and 20 inch in rear or both front and rear 24" or both 20" but may need pedal cranks for those size bikes, and smaller wheels may help more with torque n speed. years ago i put a smaller wheel in the rear and my steering was better more responsive


the pedals are more towards the front of frame behind the front wheel like a recumbent bike

cindymishler5 months ago
I need to what the gas mixture ratio is for both a two and four stroke motorized bicycle

four stroke you ad oil directly to the crankcase by opening the small round plug on the bottom not the one under the engine if its an old engine, if its the newer engine open filler cap on top of motor usually marked oil and sometimes has a dipstick oil level gauge attached to the cap,S.A.E 30 is usually recommended for small engines since its heavy duty oil or you can use all season oil that doesn't break down with varying temperatures as easy as regular oil

a four stroke doesn't need gas oil mixture only a 2 stroke needs oil to gas mix and you have to check with the motor instructions or manufacturer for the proper mix you can also look up online you motor for the fuel mix

bogyman57 (author)  cindymishler5 months ago

For two-stroke engines: you would have to check with the engine manufacturer as to their preferred ratio.

For four-stroke engines: There is none (you don't mix oil with the gasoline)

wire the dynamo to a battery case that will hold enough rechargeable AA or AAA size batteries to equal 6 or 12 volts when you stop riding the lights will stay on the dynamo will keep the rechargable batteries alive or try in place of batteries a smaller capacitor as an alternative to batteries

bogyman57 (author)  jim.cambridge.734 months ago

The dynamo that I'm using puts out 3-6 VDC @ under 5 MPH, and up to around 36 VAC @ 30 MPH. Without a rectifier/regulator circuit, I would have NiMH batteries exploding on me constantly. I'm still looking for a "smart" circuit to do the job though...

you can run a car alternator which has a rectifier n regulator in it, make a mount for it and have the alternator belt pulley wheel on the front or rear wheel or change the alternator belt pulley to a sprocket and mount the alternator with the drive chain the car alternator has a regulator in it the smallest alternator they make would be plenty

the vin# is the serial#

bogyman57 (author)  jim.cambridge.734 months ago

The VIN is on the blue sticker that came from the DMV. It was required to be installed on the bike by the inspector at the Como vehicle inspection site.

romanyacik11 months ago
Why is this in the Linux channel? It should be in either the 'outside' or 'living' category
bogyman57 (author)  romanyacik11 months ago
Why the linux channel?
I designed this project with open-source software...
Eagle CAD... [linux] and DesignSight CAD [linux]
I tried to tag it appropriately...
(and it has many other tags beside just "linux")
danny3xd1 year ago
Uber cool build Bogy. Really beautiful.

I wanted to ask why the huge rear sprocket but then you mentioned hills. She must be able to climb a tree with a 72T.
bogyman57 (author)  danny3xd1 year ago
I haven't tried to climb any trees with it yet!  (rofl)
But it CAN accelerate up a pretty steep incline!
Garadin1 year ago
If you want a lower seat, look for a 'banana' seat and modify it. My dad did that for me as a kid, and everyone tried to seal it, cause it looked like a chopper, lol.
bogyman57 (author)  Garadin1 year ago
Thanks, but I've already thought of that...
My diminutive wife has very short legs (24" long).
She won't ride it because she can't put her heels on the ground.
In retrospect, I should have started with a 20" bike - Soooo... it's MY bike now!
billbillt1 year ago
great project
rimar20001 year ago
Congratulations, it is a great achievement.
sunderman1 year ago
I didnt want to do the math when I read this, so Im just going to ask. How much did this cost in total?
bogyman57 (author)  sunderman1 year ago
It's cost me in the ball-park of $1000 (I really haven't kept track)
and I'm sure it would have cost more if I didn't work in a fabrication shop.
kprakasan2 years ago
wow truly looks like those vintage ones, i have a couple of questions , am sorry if these questions sound really retarded, is it a single speed bike , if its single speed why is the hind sprocket so big ,// if it was lil smaller wouldnt it make the bike faster , big sprockets , arent they for more torque, yea if the engine u use produce less torque then the big sprocket is to get the bike moving i guess, engine looks powerful though
bogyman57 (author)  kprakasan2 years ago
Thank you.
Yes, it's a single speed, and the big sprocket is for POWER (a.k.a. hill climbing ability)
The engine is at the maximum legal size for my region, as is its 30 MPH top speed.
kdf.inc19692 years ago
did you have to pay to get it registered? if so you just found out why it had to be registered in the first place,so somebody else could make money off of your great idea! lol. i sooo need to learn to weld. :)
Hmff2 years ago
The right way
Xthinker2 years ago
This looks amazing, I can't say anything else except that you've inspired me to want to build one. I bet your wife is happy!
TSC2 years ago
Nice man! I need to do this I have only done a weeder bike and one chain saw engine for a mini chopper that I built.
tjj07c2 years ago
did you do anything differently with the brakes or just used the original bike brakes? also, are bike tires made to go that fast?
tjj07c2 years ago
Love it, i tried doing this and the bike worked, but did not look like i wanted it to. i used a pressure washer motor and a lawnmower belt connected to a go cart pully and another smaller bike rim welded onto the actual rim. this one looks exactly like what i wanted mine to look like though.
Wesley6662 years ago
Are you sure it has to be registered and insured? I know in my area, it only needs insurance and registration if its 50cc and OVER. Under that, it doesn't have to be, however, you aren't really supposed to ride it on the road, but I have a motorized bike (Its 150cc), a 33cc scooter and minibikes galore and I have rode past cops on all of them on the road and none have given a hoot. I would stop trying to get it registered, let that be the end of it and ride it as I wanted to, where I wanted to, because in the 1 in a million chance a cop actually pulls you over, you are either going to sweet talk your way out of it (I didn't know, its under 50cc so I don't need such and such paperwork) or you get a $50 fine and I could handle a $50 ticket once, but I have been riding stuff on roads for many years and it has never even happened.

Good looking bike though! You did a great job on it!
bogyman57 (author)  Wesley6662 years ago
Yes, I'm sure.

I went to the DMV today.

Apparently, I knew more on the subject than they did!

We came to the conclusion that I have to fill out an "AFFIDADIT OF RECONSTRUCTION/SPECIAL ASSEMBLY (page 2);
Bring THAT to the inspector (along with a full set of pictures);
Pass the inspection;
Bring HIS form back to the DMV.
THEN I can apply for MOPED plates.

At least now I have a plan!

But thank you for your support (grin)

HAHA! Well good to see you doing everything by the book and actually being able to get it done!
bogyman57 (author)  Wesley6662 years ago
We'll see...

I have to get my butt out of bed at 7am to be at the inspection site by 8.

I haven't been up before NOON in TEN YEARS!!! (I work 2nd shift)

I'm not looking forward to the experience.

Is the "day-star" even out at that time of day???? (grin)
In the summer where I live it is, its usually up by 5am here and won't go away until around 11pm! Good luck with the inspection! :D
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