Fat Tire Chopper Bicycle

It's time. Building mini choppers and 2 1/2 years of dabbling with MB's It's time for me to
combine one sport bike with another.

I've spent 3 weeks working on a frame to fit a 6 ft. adult rider. I saw this frame design a
year ago and couldn't stop thinking about it so I gave it a whirl. Not as easy as I thought.

In tradition of keeping a radical bicycle look, the frame is designed with a single down tube.
Of course keeping a peddal drive train. (different than my mini choppers)

Im going with a 45 to 47 deg. rake, with a 24" 72 spoke front wheel. Chrome billet forks.
I'm not building the rear frame until I find the ultimate 11"wide x 23"tall rear tire/rim combo.
The head frame is bowed, to accept any engine style. I may start with a HT to save costs.
If I love the bike I may upgrade.

This will be a slow going project due to a busy life. This is where i'm at so far. I'll keep this
thread updated as things progress. graucho

 

[graucho]

Mitch thank you. I forgot about those guys. Do you need a wire harness to get
those lifan engines to run? Can you order one, gas it up, and kick her over? Or
How hard is the wiring config. Just wondering. graucho
http://www.hooperimports.com/product.asp?pf_id=wire_H
http://www.hooperimports.com/showpages.asp?pid=1013
http://www.hooperimports.com/product.aspx?pf_id=70cc_4A-t

 

[stude13]

i really enjoy your work. did you see the high school projects on hoopers site? im going to wire mine just as your example and pray it works. i was amazed with the power akvan had, in fact he said he could have used a 50cc and had pleanty. mitch

 

[graucho]

did you see the high school projects on hoopers site? mitch

Yes Mitch, those bikes were amazing.


I rounded up all of my axle parts. Now I can weld up the rear frame around that fat tire.

 

[graucho]

Slid the parts together to check the fit and take a peek of how it will look.

 

[graucho]

I was digging through inventory and stumbled across this minibike 97cc lifan engine I had shelved. I was doing a little dreaming and thought since I was stretching out the bike I could mount it behind the seat, and I could leave the open frame area "open". Then keeping the smell, noise behind me.

Before I took the tank off I put a little gas in it, pulled it 4 time and it fired up after 3 years. This 97cc's going to have to work a little to pull the bike. But not any more than a 250 lb. guy on a 35 lb. bike with a 20 lb. happytime.

On the other hand...I change my mind on bike designs everyday. Who knows what i'll end up with.

 

[robin bird]

Wow you sure are an incredible artist

 

[SimpleSimon]

graucho, I really admire your work. I gotta say, though - your shop is entirely unreasonably neat, tidy, and clean.

Fine stuff.

 

[graucho]

Thank you guys. My shop does get trashed often. The photos must have been on a good day.

I have been working on the rear frame and engine mount for the fat tire. Its been 8-15 degree's in the garage. Burrrrrr. I must love this ****.

 

[graucho]

I found a neat headlight from a 12v kids electric "Razor" motorcycle. In my photo its just sitting on the fork, i'll have to do a little fabricating. There are some plastic parts so we'll see if it lasts. It was free so thats no loss in $, only time.

 

[graucho]

Jackshaft set up

Here's the raw section of the jackshaft set up. the shaft will be trimmed on the final set up. Im sure i'll finetune the sprocket ratios when i'm up and running. I set the engine in place to show position.

I was asked how long the bike is? I stretched it to 7'11in. so it fits in my 8ft utility trailer. I was also asked how hot will the seat/rider get with the engine underneath/behind? There is a heat shield that mounts on top of the engine. We'll find out.