4 - stroke Schwinn Stingray Chopper occ

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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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Yea, get rid of the governor, do you know how to do that? Do you have any fabricating skills? I put a PZ19 carb on mine to waken it up, plus a pipe, but I had to make both the intake manifold and the exhaust.
id assume disconnecting the rod from the governor to the carb would do it.. but then wont the motor over rev?
i definitely dont have the tools to modify the carb.. i actually modified the exhaust to make it fit.. i had to cut the pipe down and re-weld it.
 
Yes max torque USA. I'm assuming they have a 5/8 bore one. Springs could help some but if the machining is off or the bushing wears fast it will still chatter. I had one on my second bike in my avatar picture one of the chinese crap clutches and it made the same noise.
 
id assume disconnecting the rod from the governor to the carb would do it.. but then wont the motor over rev?
i definitely dont have the tools to modify the carb.. i actually modified the exhaust to make it fit.. i had to cut the pipe down and re-weld it.
You can do it that way, but the governor gear is plastic and might not be able to take the higher rpms. The best way to do it is to take off the flywheel and then the left side cover and use a punch to knock the gear out from the right side. Get two short bolts of the right size for the holes left over from the governor removal and just thread the bolts into the case. Its aluminum so no need to tap the holes, but you can taper the bolts a bit so they thread in easier.

Don't worry about over revving, the valves will float around the 5000 rpm mark, kinda acts like a governor. You can prevent the valves from floating with stronger valve springs.

I have a cammed out GX 196 that is making close to 12 hp at 6100 rpm, but it has all the tricks added and I wouldn't recommend much more than 5000 rpm for a bike without some hi-po parts.
 
update...
it was definitely the motor... i bought a new 212cc preditor and it halls ass and i didnt even bypass the governor..
here is a video, its not that great though, i should have had the camera pointing up more.. but you can see how fast the ground is moving, especially compared to the 80CC
here is the 212cc
here is the 80cc
With the new motor, my gps was at 30MPH and i wasnt full throttle because i was concerned about a noise i was hearing and vibration.... after I inspected it, it turned out that the chain was slapping the fender.. so I added another chain tensioner.
 

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