50cc GY6 on a Bicycle??

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TIGERSHARK

New Member
Dec 23, 2014
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Tampa, FL
Hey all, so I am planning on building a MB and here in Florida I have to register the thing as a moped anyway so I was thinking, why not go with a 50cc GY6 from ebay and have a real truly clutch-less transmission and the ability to ride the thing completely without peddling if I wanted???

You can get a complete GY6 on ebay for $400 and that includes the engine (and CVT trans) the carb the CDI box and a coil.

I know there will be custom fab work involved but I have a welder and am a very skilled fabricator so that side wont be an issue.

Considering the GY6 is an engine and self contained CVT trans I am surprised more people have not used one in an MB application......

Any way let me know what you guys think.
 

Davezilla

New Member
Mar 15, 2014
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San Antonio Texas
It's all doable if you can weld and either make a custom frame to fit the engine/trans or cut out the lower frame and make up your own mounting setup. The GY6 engine would make for an interesting build tho since there's a lot of upgrades for that engine and CVT.

If you plan on using the standard 26" wheels you may need to make up some type of jackshaft since the rear of the CVT is setup to connect straight to the rear wheel and I don't know how much clearance you will have, but if you got welding and fabrication skills you should be able to get past that hurdle too.
 

Dan

Staff
May 25, 2008
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Howdy TS, welcome to the forum.

I'm also am surprised more folks don't use them. Aftermarket parts are all over the place and some cool upgrades. I have asked why more folks don't build with em.

Did a search and found this; http://www.google.com/cse?cx=partne...2561j2926149j4#gsc.tab=0&gsc.q=GY6&gsc.page=1


Picture from this thread;

http://motorbicycling.com/showthread.php?p=578480

Really looking forward to seeing what you do. Post lots of pics.

I am most curious about the sprocket mount and ratio your gonna use.

I was thinking to make up for the larger rear wheel, use a larger driven in the transmission and a longer belt. I was gonna aim for a mid range of 12:1.....

Now I wanna buy one just to experiment, lol.
 
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mapbike

Well-Known Member
Mar 14, 2010
5,502
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Central Area of Texas
Ive got a 150cc GY6 chinese clone on a Roketa china scooter, Ive thought about a stretched out bike build with one myself but dont know if I'll ever do it or not, the 150's with some mods like mine have a lot of torque and my scooter will cruise @ 63-64 mph on the flat without anyone head wind, for a 200+lb scooter pulling a 215lb man than just aint really that bad for a cvt drive 13" rear wheel.

Id think a 50cc like was mentioned would be a better engine for a bike build and then maybe mod it with one of the inexpensive 80cc kits for an excellent powerplant, all the GY6 engines ive been around are gas sippers also, I have got around 80+ mpg on my scooter if I dont run it down the road at 6500-7000rpms to much.

map
 

cannonball2

Well-Known Member
Oct 28, 2010
3,682
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Colonial Coast USA.
I also have a modded 150 GY6 in a Ruckus clone. They are excellent engines, there are a ton of mod parts for them and they are cheap. Being in the flats I exchanged final drive gears for a much taller ratio. It will top just over 70 but it has a much more relaxed cruise at the 55/60 where I like to ride. It would be an interesting build around a bicycle. Would certainly require some wheel/tire/brake upgrades. Cool thing is these power units are super reliable even modded, and the CVT is highly tunable.
 

Davezilla

New Member
Mar 15, 2014
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San Antonio Texas

cannonball2

Well-Known Member
Oct 28, 2010
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Colonial Coast USA.
Heres a couple of pics of my scoot. Chose the Ruckus style as the engine is instantly accessible. Paid $699(plus shipping of course) and probably spent more than that in mods. You can forget the iffy experiences with the CG engines with the GY6. This is of course a Honda designed unit and I understand in the latter years of usage by Honda some were made in China, so they (then) were built to Hondas standards. Still seem to be. Some times the scooter part is a bit crude in execution but the engines seem to all be of good quality. I have run the absolute crap out of this one with no issues. The engine is modded with a big bore kit, high comp big valve head, perf cam, 30mm carb with free flow intake clocked to face the front, unlimited CDI, header/free flow exhaust and a hi-torque starter to handle the increased compression. The CVT has just about as many upgrades. Swapping weights is a snap(you can even mix em) to get just the curve you want. I also upgraded the stock wheels to 3" wide version with sticky higher speed rated tires, along with the brakes. Handling is excellent for a scoot.
Acceleration is immediate and I surprise a lot of M/C riders for the fist couple of hundred feet at traffic lights.

Somebody please do a build bike around one of these!
 

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mapbike

Well-Known Member
Mar 14, 2010
5,502
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Central Area of Texas
Heres a couple of pics of my scoot. Chose the Ruckus style as the engine is instantly accessible. Paid $699(plus shipping of course) and probably spent more than that in mods. You can forget the iffy experiences with the CG engines with the GY6. This is of course a Honda designed unit and I understand in the latter years of usage by Honda some were made in China, so they (then) were built to Hondas standards. Still seem to be. Some times the scooter part is a bit crude in execution but the engines seem to all be of good quality. I have run the absolute crap out of this one with no issues. The engine is modded with a big bore kit, high comp big valve head, perf cam, 30mm carb with free flow intake clocked to face the front, unlimited CDI, header/free flow exhaust and a hi-torque starter to handle the increased compression. The CVT has just about as many upgrades. Swapping weights is a snap(you can even mix em) to get just the curve you want. I also upgraded the stock wheels to 3" wide version with sticky higher speed rated tires, along with the brakes. Handling is excellent for a scoot.
Acceleration is immediate and I surprise a lot of M/C riders for the fist couple of hundred feet at traffic lights.

Somebody please do a build bike around one of these!
Nice looking scoots, mine isn't nearly as mod'd out as yours, just a better exhaust, jet size increase in stock carb, unlimited CDI, high energy coil, and some minor upgrage to the CVT which sin't any where near where it needs to be yet.

These engine are a blast to tinker with and they really run a hole in the wind for their size, some of my friends and family have been really impressed with how well this thing will get up and go for a little 150cc engine on a chinese scooter, these scooter are the best thing I've had for zipping around town on, so easy to handle and plenty of power and speed to run with traffic around town.

GY6 clones are very reliable little engines and there is almost an endless supply of upgrades internal and external for these engines.
 

Dan

Staff
May 25, 2008
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I let myself (so my fault) get talked out of building with one when looking for a next project. CB and Map, if'n you 2 like them, wow, am gonna get one next round.
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
I let myself (so my fault) get talked out of building with one when looking for a next project. CB and Map, if'n you 2 like them, wow, am gonna get one next round.
Dan, one of my younger brothers had a 50cc and he tried to tare it up the way he road it and it never missed a beat, it finally got hard to start and then finally wouldn't start at all after no telling how many very hard miles, he parked it for a while thinking maybe he had killed it, I ask if he'd let me tinker with it a bit and he agreed, I changed CDI, spark plug, checked carb for any noticeable issues, even ran a compression test and all seemed to be perfect, even checked stator thinking something could be wrong there.

Finally it dawned on me to pull the tappet cover and check valve clearance...Bingo...! thats all the little gal needed was a simple adjustment, I set the valves to spec and she busted right off and ran like a brand new scooter... the little 50cc wouldn't do but 38-39mph on the flat, but it was smooth as silk and plenty peppy up to top speed, I'll bet one of the 50cc engines with an 80cc top end kit would be a fun set up on the scooter or on a bike build for sure.
 

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
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The biggest hurdle to using the common scooter mill is the chain drive since most are setup for a scooter drive wheel. The key is to find one of the versions used on the 4 wheelers since they already HAVE a chain drive conversion box.
Using this version, all you have to deal with is the extra length!
And BTW, the HUGE number of available upgrades for these motors can make them quite powerful and rawkus!
 

cannonball2

Well-Known Member
Oct 28, 2010
3,682
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Colonial Coast USA.
I a 49cc that had a complete 80cc kit, cyl/piston, head, carb, ext, etc. It was pretty much a screamer for what it was. Whats cool as long as the sn begins with 139QMB the law thinks its 49cc. You can get a complete 150cc shipped to your door for $299. Should be a simple matter to engineer a drive off the cvts wheel shaft. They are electric and kick start and will start on an R/C lipo battery. Also have a reasonably hefty charge system too. Properly setup the cvt preforms as well as a manual trans and is much easier to deal with. It will supprt the bike as a suspension member and runs a single shock and has an excellent drumbrake, though the drum is intregral to the scooters wheel.The possibilities are wide open to creative building
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
Yes the Go Karts and 4 wheeler use what they call the short case version and they are normally set up for a 40 or 420 chain but the CVT belt runs to a assembly or gear box that goes to a chain drive down to the axle, some of the go karts even have a reverse....

wouldn't that be wild on a bicycle..!

The short case engine are higher too.

A stretched out bike frame and a well built jackshaft set up would be the way I would go with a long case engine if I were to build one, get the splined inset from a rear wheel and weld the desired sprocket onto that and then a chain from there to a jackshaft and from there to the wheel is the first design that comes to mind without thinking to much about it.

http://www.amazon.com/gp/product/B0...d_t=201&pf_rd_p=1944687462&pf_rd_i=B008MQ38EY

loads of parts

http://www.motopartsmax.com/index.php/main_page/parts_asse/asseModes/asseby_engine/paID/40

http://www.partsforchinesescooters.com/

http://www.monstergy6.com/

Here is a little info you may find interesting about the GY6 and a place that sells some stuff for them also.

Can you say 12,000 RPM 4 stroke capability...LOL!

http://gokartsusa.com/hondagy6engine.aspx
 
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Dan

Staff
May 25, 2008
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LOL, be a heck of a sobriety test.

Heard in the ER; "So you were riding a bicycle with a motor attached and going backwards?"