4 - stroke Schwinn Stingray Chopper occ

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#1
Related to this post: https://motoredbikes.com/threads/pr...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
 
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Timbone

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#2
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!
 
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#3
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.
 
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#4
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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#6
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.
 
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#7
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

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#8
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.
 
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#9
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?
 
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#11
hey KC, is there a certain place you buy your extra long throttle cables? i have a build going that has 22” ape hangers on it and i can’t seem to find a long enough throttle cable.
 
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#13
Just few updates over this weekend:
- As KC suggested, throttle cable is too short, I ordered the longest one in Gasbike: 80'', planning to put it underneath the bottom of the frame and coming up from the back of the frame to the engine.
- I tried to install the motor, looks like the clamps are gonna work, I believe I have 1/4 to 1/2 inch between the chain and the back tire with the motor a little bit moved to the left (not completely centered on the frame), I have to cut the clumps in order to do a test installation, but I believe it is gonna work, I'll upload pictures of how it looks like.

Off-topic: driving my 2-stroke Tuesday night throttle cable broke half way home... I'm sure was funny to see me driving with one hand and pulling the broken cable from the carburetor with the other... Now I have a use for the throttle cable that came with the 4-stroke kit.
 
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#14
Finally I had time to work on this!

I was able to install the motor with few modifications on the original bracket and the two u-clamps. The most important trick is how to bolt the motor to the bracket, I installed it with the part that usually points back pointing front and installing the motor as left as I can, then, only two screws will touch the frame of the bike, so I installed other two screws nutted on the motor side, check this pic, it's easy to show than to explain... BTW, I used the hex nuts than usually are used for the bracket instead of the black ones that are for the motor, because the hex ones gave me more stability touching the frame.

019.33894130_std.JPG


I had to drill the interior of 4 nuts because the tread of the u-clamps was not going to the base of the bracket, so now they are "nut-washes":

IMG_20171104_105745.jpg

I had to cut part of the choque plastic tip because it didn't fit, but you can still use it with no troubles, moving it from the base of the plastic:

IMG_20171104_110923.jpg


This is how it looks like, looks like double nutted, but only one nut has thread:

IMG_20171104_110724.jpg


Here how the u-clamp looks like underneath:

IMG_20171104_110852.jpg


Here how it looks like with the chain on:

IMG_20171104_140347.jpg


Pic from the "ugly" side:

IMG_20171104_143540.jpg


Final picture of the work:

IMG_20171104_143655.jpg


I still need to put some oil and gas on it to do the first run, but it was too late already, so I hope I can test it out today or tomorrow.

Things on my to-do list:
- Chain is only about 2mm from the tire, good enough for now, but something to improve.
- I have other muffler to install, but I have to modify because it doesn't fit with this frame.
- Gas tank is hold only with two nuts, good enough for now.
- Chain tensioner nuts are on the tip of the screw, I need longer screws.
- I had to remove the back wheel fender, I have to trim it to fit the chain and re-install.
 

Timbone

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#15
Finally I had time to work on this!

I was able to install the motor with few modifications on the original bracket and the two u-clamps. The most important trick is how to bolt the motor to the bracket, I installed it with the part that usually points back pointing front and installing the motor as left as I can, then, only two screws will touch the frame of the bike, so I installed other two screws nutted on the motor side, check this pic, it's easy to show than to explain... BTW, I used the hex nuts than usually are used for the bracket instead of the black ones that are for the motor, because the hex ones gave me more stability touching the frame.

View attachment 79796

I had to drill the interior of 4 nuts because the tread of the u-clamps was not going to the base of the bracket, so now they are "nut-washes":

View attachment 79789

I had to cut part of the choque plastic tip because it didn't fit, but you can still use it with no troubles, moving it from the base of the plastic:

View attachment 79795

This is how it looks like, looks like double nutted, but only one nut has thread:

View attachment 79790

Here how the u-clamp looks like underneath:

View attachment 79791

Here how it looks like with the chain on:

View attachment 79792

Pic from the "ugly" side:

View attachment 79793

Final picture of the work:

View attachment 79794

I still need to put some oil and gas on it to do the first run, but it was too late already, so I hope I can test it out today or tomorrow.

Things on my to-do list:
- Chain is only about 2mm from the tire, good enough for now, but something to improve.
- I have other muffler to install, but I have to modify because it doesn't fit with this frame.
- Gas tank is hold only with two nuts, good enough for now.
- Chain tensioner nuts are on the tip of the screw, I need longer screws.
- I had to remove the back wheel fender, I have to trim it to fit the chain and re-install.
Looks like you resolved all the pertinent issues! Congrats! Have fun and be safe!
 
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#17
Brief update: motor works and pulls, able to start moving from stop with no pedaling. Don't know about max speed, not tested yet at all, but feels with enough torque, more or less (I'll say more, but maybe because of the excitation) like my two stroke.

Now, comparing the two stroke with the four stroke, I'll buy 4 stroke again... It is true that I'm not comparing apples to apples, because this is a good 4 stroke kit and my 2 stroke is an old China girl that I found on the street... But still, no vibration, solid construction and the centrifugal clutch are my new best friends.
 

Frankenstein

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#18
What I never understood is that the engine is fine for burning fuel and powering equipment, unless you put it on a motherfreaking road, then all a sudden it's no longer OK.

But anyway that's a fun looking bike, gear down to like a 30 tooth or something near that since a 44 gets a whopping top speed of 15 with that tiny rear wheel. My friend recently completed a 212 in a stingray frame and is currently stretching and installing another in the same type of bike, does wheelies off the line and 45mph at least for the top speed.. Lol I think a 79 would be a nice in the middle for that bike and it would just fit without changing up the frame.
 
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#19
What I never understood is that the engine is fine for burning fuel and powering equipment, unless you put it on a motherfreaking road, then all a sudden it's no longer OK.

But anyway that's a fun looking bike, gear down to like a 30 tooth or something near that since a 44 gets a whopping top speed of 15 with that tiny rear wheel. My friend recently completed a 212 in a stingray frame and is currently stretching and installing another in the same type of bike, does wheelies off the line and 45mph at least for the top speed.. Lol I think a 79 would be a nice in the middle for that bike and it would just fit without changing up the frame.
I have a 36t on the back wheel and an 80 on the transmission, my calculations are that it will get at least 30mph, but with the stock brake I don't want to try it...
 

KCvale

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#20
I had to cut part of the choque plastic tip because it didn't fit, but you can still use it with no troubles, moving it from the base of the plastic:
I have to cut the choke plastic lever down on many 4-stroke builds.

The trick is to epoxy the lever back on, but if you can do that you can orient the lever however you want, like off to the side.



Just a tip ;-}
 
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