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]

The bike touches the ground finally

The fat tire chopper touched good ol' mother earth for the first time. Before proceeding I had to take it off the bench and ride it to test tracking/balance. Wow! she tracked PERFECT! Straight as an arrow. Way easier to ride as I thought. Pedals like a dream. The jackshaft/freewheel worked perfect. I'll have to spin the neck head around so the handlebars are 4 inches forward. Other than that nothings changing.

She can go back up to the bench to mount the throttle, brakes and fuel tank. Then back to the ground for a gas powered test ride. I cant wait. I'm probably 8 hrs away from being able to disassemble and paint. I've got all the parts needed for completion. All of the electrical is in order.

Here's a few shots of it on the ground. I shot a photo of it next to my daughters car to see what 7ft 11in looks like.

 

[srdavo]

freaking AWESOME!!!

that engine sure tucks in there nicely....almost don't notice it!! how many HP ?

nice work.... really nice work!!!

 

[Irish John]

Brilliant Graucho I'm in suspenders waiting for the powered trial but the pedal chain needs tensioning or tightening beforehand.

 

[graucho]

Brilliant Graucho I'm in suspenders waiting for the powered trial but the pedal chain needs tensioning or tightening beforehand.

Thanks guys.

Dave, 49cc of course.

Irish John, Yes sir re' I'll have to fine tune everything on the final reassembly after painting. I have to trim the jackshaft, mess with sprocket size for the gas powered section to regulate speed etc. etc. The bikes pedal chain is about 1/2 link away from taking a link out. I'm hoping I can stretch it out a bit by riding it a little. Or i'll shift the jackshaft back a pinch.

I think i'll paint it the same color scheme as the seat. Black in the back, fading into burnt orange/red, fading into yellow at the front. I've done this vigynette effect a few times with success.

 

[DetonatorTuning]

HEHE that is AWESOME.

how much air you got in the back tire to put that crown on it ?

steve

 

[graucho]

HEHE that is AWESOME.

how much air you got in the back tire to put that crown on it ?

steve

Thanks steve, the tire is a 12" rim with a 22" tall golf cart tire. (all mini chopper builds use the DOT golf cart tire) If installed on a golf cart you would need the lift kit installed. It just has the recomended 32 PSI. I'll have a detailed list of all suppliers and parts at the end of the build.

 

[graucho]

A few additions/updates

Found some braided stainless casings for the throttle and brake cables. Then welded on tabs to thread them through heading to the disk brake and engine throttle. (Not using zip ties this time like my other store bikes) All electrical wires will pass through inside the frame. Everything is in the raw stages and not adjusted for sagging or final cable lenght. Just a few quick shots.

Then found a set of caps to go onto the threaded rear axle ends. There very dangerous because of the pointed ends. I may have to shave 1/8 off of them so I dont stab myself. (It will happen) LOL. I have to keep them, im diggin the look.

 

[Irish John]

She's looking good Graucho. Is that braided cable encased in plastic? Where did you get it? The whole shebang is starting to gel now. I hope she goes like a rocket.

 

[graucho]

Hey John. Thanks man. Here's the scoop. Yes, they are also coated with graphite inside so the cable slides SMOOTH in the casing. No lube needed. Take care.

Cable casing
4th one down.
http://www.choppersus.com/store/category/7/41/Cables/

Cable Ferrules and cable frey end caps. (You could get then at a local bike store)
http://www.choppersus.com/store/category/7/43/Brake-Parts-Hardware/

Control Rod Anchor. (I drilled a 2nd hole in them)
http://shakyparts.com/control_rod_anchor.html

 

[graucho]

We had a little warmer temps the last 4 days so I totally disasembled the bike. Then I finished the bodywork and took it to primer. Now she sits to cure and waits for a 70 deg. day to paint. (Automotive sandable red oxide scratch filler primer. Sprayed with a wide nozzle airbruch pen)