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  #51  
Old 04-17-2016, 03:01 PM
Austritch Austritch is offline
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Default Re: 50cc GY6 on a Bicycle??

Hey! I am building a fat tire (mongoose dolomite) custom frame and gas tank bike. My mandatory specs were that it had to have disc brakes front and rear, 4 stroke motor, and shift with no manual clutch (shifter kit from Bike Berry). The problem I am having seems to be that the 49cc motor (also from Bike Berry) is under powered for the gearing and is frying my centrifugal clutches. I am thinking about going with a 150cc Gy6 motor. Do you think this is the right thing to do? Perks to the Gy6 motor are that parts are readily available, speed will be more comfortable, and a kick starter. My build is more of a motorcycle style than a pedal bike. I am still trying to utilize the original rear cassette and shifter so that I may run through all 7 gears for a more useable ride. Rather than going with a larger single gear, I am thinking about using a more powerful motor. Hence the 150cc Gy6. Does anyone have any experience with using a Gy6 150 on a motorized bicycle?

While I have the bike on the stand, it will run perfectly fine and shift through the whole cassette. But while under actual load, it barely moves under its own power.
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  #52  
Old 04-17-2016, 05:17 PM
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Ludwig II Ludwig II is offline
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Default Re: 50cc GY6 on a Bicycle??

My first question is what the reduction ratio is between the output of the engine and the largest of the sprockets you have. If the gearing is too tall, that will explain the fried clutches.

Can someone give a ballpark set of figures for the right number of teeth on the driving and the driven?
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  #53  
Old 04-17-2016, 07:11 PM
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cannonball2 cannonball2 is offline
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Default Re: 50cc GY6 on a Bicycle??

You haven't given much info on how the bike is configured. Generally there is a jackshaft required to transfer the drive to the derailleur, and the ratios are very important as L2 has indicated.

I am assuming you are running the 4stroke engine. Depending on which kit you bought you may have the one with the 3:1 pocket bike trans. This kit has too little primary reduction, it should have a 5:1 reduction to make it work well. I have one of these. When I bought it I assumed a 5:1 box. They don't tell you its a 3:1. Maybe this is part of the problem?

I have a ton of hands on with a 150cc Gy6 in a Honda ruckus clone scooter. I extensively modded the engine and variator. It will easily show the north side of 70mph.
They are wonderful powerplants. However for modding to a bike it will require some pretty good fabbing as its an engine/trans unit that is also the rear suspension. I suppose the rear triangle could be removed from the bike and the Gy added to the frame some how. But running a scooter sized wheel would be required as the final ratio would be way out of wack for a bike wheel. Not trying yo discourage you if you have the skills go for it. Just pointing out a few facts.
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  #54  
Old 04-17-2016, 11:33 PM
Austritch Austritch is offline
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Default Re: 50cc GY6 on a Bicycle??

Here are some pics of the build:
Attached Images
File Type: jpg pic1.jpg (69.3 KB, 9 views)
File Type: jpg pic2.jpg (11.9 KB, 8 views)
File Type: jpg pic3.jpg (359.2 KB, 12 views)
File Type: jpg pic4.jpg (295.5 KB, 11 views)
File Type: jpg pic5.jpg (109.2 KB, 7 views)
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  #55  
Old 04-17-2016, 11:34 PM
Austritch Austritch is offline
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Default Re: 50cc GY6 on a Bicycle??

Even more pics:
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File Type: jpg pic6.jpg (268.0 KB, 7 views)
File Type: jpg pic7.jpg (271.4 KB, 7 views)
File Type: jpg pic8.jpg (104.5 KB, 4 views)
File Type: jpg pic9.jpg (117.0 KB, 5 views)
File Type: jpg pic10.jpg (69.6 KB, 5 views)
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  #56  
Old 04-17-2016, 11:36 PM
Austritch Austritch is offline
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Default Re: 50cc GY6 on a Bicycle??

And more pics:
Attached Images
File Type: jpg pic11.jpg (266.5 KB, 5 views)
File Type: jpg pic12.jpg (107.7 KB, 6 views)
File Type: jpg pic13.jpg (96.7 KB, 6 views)
File Type: jpg pic14.jpg (98.0 KB, 4 views)
File Type: jpg pic15.jpg (223.9 KB, 5 views)
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  #57  
Old 04-17-2016, 11:44 PM
Austritch Austritch is offline
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Default Re: 50cc GY6 on a Bicycle??

This is the exact gear kit that I ordered:
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File Type: jpg pic16.jpg (79.6 KB, 8 views)

Last edited by Austritch; 04-17-2016 at 11:46 PM.
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  #58  
Old 04-18-2016, 05:39 AM
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Ludwig II Ludwig II is offline
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Default Re: 50cc GY6 on a Bicycle??

This business with the transmission case, why not cut out a section in the middle and use a shorter drive belt? It should be possible to make up brackets or flanges as well to bring the cut faces to each other, so giving a clean and safe primary drive to what is now the 1st reduction in a 2 stage transmission.
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Last edited by Ludwig II; 04-18-2016 at 05:44 AM.
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  #59  
Old 04-18-2016, 06:51 AM
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cannonball2 cannonball2 is offline
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Default Re: 50cc GY6 on a Bicycle??

While that may be plausible L2 it would be quite a bit of work.

That still leaves the issue with gearing being based a 10/12" wheel. Not an issue if running a smaller wheel in the rear is acceptable. There are plenty of optional final gear sets but I doubt any low enough to accommodate a bike size wheel. Of course one could run a small front wheel to balance things. Might be a 21st century Cushman.

Austrich, the reduction I am referring to is the case on the engine. It looks like a 3:1, The 49cc really needs a 5:1 and the more expensive kits come with them. You can determine by removing the reduction(4bolts) and counting how many turns the clutch drum makes for one turn of the sprocket. I'm betting 3.
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  #60  
Old 04-18-2016, 07:52 AM
curtisfox curtisfox is offline
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Default Re: 50cc GY6 on a Bicycle??

Quote:
Originally Posted by Austritch View Post
And more pics:
First picture looks like you have a small sprocket on the engine side and a big one on the drive side. That is stepping up the ratio, should be changed around with the big gear on the engine side...............Curt
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