4 - stroke Schwinn Stingray Chopper occ

dmopedMA

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Apr 14, 2017
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161
Related to this post: https://motoredbikes.com/threads/preparing-a-new-build-on-a-schwinn-stingray-chopper-and-im-looking-for-some-advice.50872/

Donnor bike:
IMG_20171001_111755.jpg


Since this is not being an standard build (as expected) I'm going to describe how I'm solving the issues that I'm having, I hope it will be useful for someone.

First thing, choosing the motor kit: after digging and asking around I decided to go for
I ordered this kit: http://www.bicycle-engines.com/49cc-4G-T-Belt-Drive-Complete-Gas-Powered-Engine-Kit.html
I didn't know if to get the 100 or the 80 tooth pulley, I asked on the chat that they have and.... I believe the person behind didn't know much about what she was talking about... I asked which configuration will be faster and she told me the 100 tooth... After checking the manual that comes with the engine, that is wrong, 80 has a "faster" ratio, 100 is for better hill climbing and torque. Because of this I ordered a smaller sprocket (36 tooth), I'll get a Engine rpm to bike wheel rpm ratio of 18, close to what you get with the 80 on the transmission and a 44 on the wheel (17.6).
[UPDATE]
After contacting BE, they are sending me a 80 tooth transmission to exchange with the 100 one, I don't have to pay for anything, amazing customer service!

IMG-20171006-WA0006.jpg


Pieces I've ordering so far (updated on Apr 2018):
- 49cc 4G T Belt Drive Complete Gas Powered Engine Kit - 80 tooth transmission (from Bicicle-engines) (firt transmission was a 100 tooth by mistake, exchanged with a 80 tooth)
- 2 Piece Muffler "Poo Poo Pipe" Deluxe For 4 Strokes
- Flexible muffler tube (eBay)
- 36 tooth sprocket (Amazon)
- 40 tooth sprocket (Amazon) <- using this one
- Sunlite D-Cruiser Handlebar, 32" W x 13.5" H x 7/8" - Hi-Rise handlebar
- 2 x 2,5 inch U-clamps with nuts and washers
- Front wheel, being a 24'' back wheel with free-wheel to install disk brake
- Disk brake kit for free-wheel (BlueSunshine Front and Back Disk Brake Kit - 160mm For 80cc Gas Motorized Bicycle - Amazon)
- Front fork with suspension

First thing is holding the motor to the bike, the engine bracket that comes with the motor si not compatible with the frame, and indeed, there is no much room to play around in the frame, so I have to remove pedals, bike chain and the chain cover, after that still, really tight, so I cut a portion of the chain cover holder, like in the picture:

IMG_20171007_153759.jpg


After thinking about different options, I come up with a solution, using the central part of the bracket drilling 4 holes (picture only has the first two) on each side of it, so I can use 2 u-clamps to hold it to the bottom part of the frame of the bike

IMG_20171008_214141.jpg


After first try, looks like it is gonna make the trick, the round part of the u-clamp is kind of the same round that the frame, so it adjust well, on the other side, part of the unthreaded u is coming out of the bracket, so I need some washes or something, and of course, I'll have to cut the u, it is way too long.

So far Is what I did (as October 8th). I'll keep updating as I work on it.

November 5th update -> https://motoredbikes.com/threads/4-stroke-schwinn-stingray-chopper-occ.51001/#post-451003

Video of the first start of the motor (Nov/05) -> https://motoredbikes.com/threads/4-stroke-schwinn-stingray-chopper-occ.51001/page-2#post-451198
 
Last edited:


Timbone

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Apr 20, 2014
Messages
1,102
Yes, you found a major issue with motorizing the Schwinn OCC Chopper. Without modification, the engine will not center in the frame. The usual solution (and the one I employed) was cheating the engine to the left - I think it is an inch to an inch and one half.

I've never played with 4 strokes and the motor mount used with them, so I am curious to see how your solution works! Good luck with the build!
 

dmopedMA

Active Member
Joined
Apr 14, 2017
Messages
161
Yes, you found a major issue with motorizing the Schwinn OCC Chopper. Without modification, the engine will not center in the frame. The usual solution (and the one I employed) was cheating the engine to the left - I think it is an inch to an inch and one half.

I've never played with 4 strokes and the motor mount used with them, so I am curious to see how your solution works! Good luck with the build!
Thanks! 4-stroke are wider than 2-stroke so I believe is gonna be easier, still chalengy.
 

dmopedMA

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Joined
Apr 14, 2017
Messages
161
Just a small update: I contacted Bicicle-Engines about the issue with the wrong tooth pulley, they are going to ship a 80 tooth transmission with a shipping label to return the 100 tooth all for free.
Today I'm really grateful to KCvale, I'm ordered from them because of him.
 

Timbone

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Apr 20, 2014
Messages
1,102
Another thing about these OCC Choppers: they have very strange design that affects their steering. Mine had very little trail but the stock bars were super wide, adding lots of leverage and really helping at speed. I'd do some testing with various bars to see which is safest.
 

dmopedMA

Active Member
Joined
Apr 14, 2017
Messages
161
Another thing about these OCC Choppers: they have very strange design that affects their steering. Mine had very little trail but the stock bars were super wide, adding lots of leverage and really helping at speed. I'd do some testing with various bars to see which is safest.
Thanks for the tip, I'll keep that in mind. So far, this handlebar is wider than the original, so more leverage (I guess).
 

KCvale

Motorized Bicycle Vendor
Joined
Apr 18, 2010
Messages
3,518
So far, this handlebar is wider than the original, so more leverage (I guess).
You are going to need an extra long throttle cable with those ape hangers on it.







I did a stingray but can't find the pics just now, but you get the idea.
 

dmopedMA

Active Member
Joined
Apr 14, 2017
Messages
161
You are going to need an extra long throttle cable with those ape hangers on it.







I did a stingray but can't find the pics just now, but you get the idea.

I see, is that any kind of special cable or is the same than the brake or the gears one?
 

KCvale

Motorized Bicycle Vendor
Joined
Apr 18, 2010
Messages
3,518
I see, is that any kind of special cable or is the same than the brake or the gears one?
Only the throttle cable, it has fittings on each end.
Don't stress about that, you have way more important challenges ahead of you.
 
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