jtryba Posted @ 19:58:12 on 2014-07-06

Mini Chopper 2

I started with one of those Schwinn WCC Choppers:

Only mine didn't come with the fender, as it was used.

I then acquired a Honda clone engine (GX200) 6.5hp 4 cylinder
horizontal shaft OHC engine


I Modified the frame to support the engine:








More to come...

-jtryba
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jtryba Posted @ 20:23:34 on 2014-07-06

I got another picture, one with the engine in place.

-jtryba
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jtryba Posted @ 13:33:50 on 2014-07-13

I have replaced the head with a performance race ready head, and installed 18 lb valve springs.

I also replaced the stock cam with a CL2 class race cam.

I advanced the timing by 8 degrees. (Every 0.006 inches you remove from the key is equal to 1 degree advance. So if you remove 0.048 inches you will have 8 degrees advance.)

I bought a race ready carb (jetted @ .038/.022) and installed an aftermarket air filter.

I'm running the stock electric start flywheel.

I built a rear rim, and a front fork.

Installed a headlight (fog light for a car) and a tail light. (trailer blinker)

Installed an electric starter and battery charging coil. (had to notch the frame for it to fit...)

I will get more info and pics posted soon.

-jtryba
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jtryba Posted @ 18:52:14 on 2014-07-20

I took it out on a private road today, I got it up to 55 mph.

I'm running a 12 tooth clutch and a 70 tooth sprocket on the rim, with #35 chain. That's a 6:1 gear ratio with my 20 inch wheel.

-jtryba
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jtryba Posted @ 11:03:32 on 2014-07-26

Some more pics....





Full album here.

-jtryba
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jtryba Posted @ 20:21:08 on 2014-08-07

Got my 18 lb. Valve springs and installed them.

-jtryba
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jtryba Posted @ 13:01:13 on 2014-08-08

more pics...

-jtryba
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jtryba Posted @ 15:06:52 on 2014-08-15

Too much torque, it ripped the rim apart.
I had to fab up a new one, this time instead of using a freewheel style rim, i went with a stronger coaster brake style rim. It took a few more steps to convert it but was worth it I think. I was able to fit a wider tire on the new rim.

Just as a side note for anyone else attempting to convert a 20 inch bicycle rim for use with a 6.5+ hp motor:
This was the second rim the engine ripped apart, irrelevant, but the first rim the engine ripped apart was because the discs on the hub that have all those holes in them for the spokes were only pressed onto the hub.
So make sure to TIG weld those onto the hub before attempting to weld any sprockets to the hub.
I'll make a tutorial for converting both style rims as i get them, as of right now I am out of rims i have not converted yet, sorry.

-jtryba
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jtryba Posted @ 15:10:37 on 2014-08-15

Currently I'm working on implementing disc brakes in the rear.
I plan on ordering a generic go kart brake caliper, a brake rotor with 4 bolt holes on a 3 inch circle, and fabricating my own hub or just get one machined to mount the rotor to that i will weld to the rims hub.



EDIT:
I did get the hub machined, cost me $60, and I welded it to my rim.
I also got a 8-1/4(8.25) inch x 1/8(0.125) inch rotor and bolted it on.
Ill get some images posted soon.

-jtryba
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jtryba Posted @ 10:50:28 on 2014-09-19

-jtryba
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jtryba Posted @ 10:56:37 on 2014-09-19

-jtryba
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jtryba Posted @ 15:23:04 on 2014-10-17

I recently wrote a small app in java (called speedCalc) to help choose what gears to use in your own project, link.

-jtryba
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jtryba Posted @ 10:36:21 on 2016-07-08

Lol, tore that rim apart too... replaced with a moped rim this time. No more disc brakes

Also gave it a paint job

*NOTE: I'm still working on the wiring after reassembly. (thats why there all over)

-jtryba
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