Larger clutch than normal

T

Thewurst

New Member
Ok so I bought this bike with the kit, it looks to be an 2007 RB4-50 kit from what I can research. the clutch and mounts are larger than the standard kits. My clutch is 86mm (probable 85 from factory, but lost a mm from wear) inside diameter, and my mount holes are 75mm center to center.

the final gears in the case are worn down and need to be replaced. either that or get a whole new transmission, as long as it will fit it doesn't have to be the same model. here are some pics

3k63K53Lb5G85E85Had3e8aaedcfe24dc1a68.jpg

3F73Lc3Nb5N75G95H4d3e29bf967aac991a43.jpg
 
It's a 49 cc Huasheng motor with the dreaded and much derided
"Hoot" gearbox which isn't worth fixing.

That version of the Huasheng motor has a turned down shaft which
will need to be shimmed to work with a replacement gearbox.

The Grubee 4 G from Bicycle-Engines.com would be my first choice at ~$140
EZ Motorbike Q Matic at around $300?

Take the gearbox off and measure the shaft diameter.

It's funny that your exhaust is an expansion chamber that will only give you a
performance increase on a 2 stroke. :)
How does that sound?

Sell it and put a straight pipe on with a Briggs cigar muffler.

Good Luck!

Thewurst said:
Ok so I bought this bike with the kit, it looks to be an 2007 RB4-50 kit from what I can research. the clutch and mounts are larger than the standard kits. My clutch is 86mm (probable 85 from factory, but lost a mm from wear) inside diameter, and my mount holes are 75mm center to center.

the final gears in the case are worn down and need to be replaced. either that or get a whole new transmission, as long as it will fit it doesn't have to be the same model. here are some pics

3F73Lc3Nb5N75G95H4d3e29bf967aac991a43.jpg
Click to expand...
 
Last edited:
i plan to scrap the transmission, but I would like to save the motor. those are the craigslist pics from the previous owner. i was just wondering if I can bolt on any other transmissions
 
Thewurst said:
i plan to scrap the transmission, but I would like to save the motor. those are the craigslist pics from the previous owner. i was just wondering if I can bolt on any other transmissions
Click to expand...
Yes, it's a good motor.
1st post said:
The Grubee 4 G gearbox from Bicycle-Engines.com would be my first choice at ~$140
EZ Motorbike Q Matic at around $300?

Take the gearbox off and measure the shaft diameter.
Click to expand...
 
ok what if I turned down the shaft to fit the smaller clutches on, like this one? http://www.ebay.com/itm/CLUTCH-3-ba...Parts_Accessories&hash=item58853566dd&vxp=mtr

I really like this cvt trans, it will get me alot more speed. http://www.ebay.com/itm/49cc-X1-X2-...Parts_Accessories&hash=item256be5851d&vxp=mtr

that trans has enough extra aluminum around the bolt holes to allow me to drill out the holes to fit onto my motor. I will have to turn down my shaft to 11.8, and shorten it and re-mill the keyway. I am in highschool so i can machine for free! but the dealbreaker- is this even a good, reliable trans?
 
That CVT sucks way too much power for the 2 HP Huasheng and
I am pretty sure that it spins the wrong way like Clockwise because
it is designed to run on the right side of the pocket bike.

The CVT won't give you any more speed and it would add a LOT
of width to your motor.

I have been fooling around with Motorized bikes for over 5 years
and you aren't going to come up with a gearbox better than The 4G
for the price. :)
The EZ Motorbike Q Matic is good too if you want to spend more.

You may need to turn down the shaft for the 4G for a very good
ball bearing mod for the 4G gearbox.

Thewurst said:
ok what if I turned down the shaft to fit the smaller clutches on, like this one? http://www.ebay.com/itm/CLUTCH-3-ba...Parts_Accessories&hash=item58853566dd&vxp=mtr

I really like this cvt trans, it will get me alot more speed. http://www.ebay.com/itm/49cc-X1-X2-...Parts_Accessories&hash=item256be5851d&vxp=mtr

that trans has enough extra aluminum around the bolt holes to allow me to drill out the holes to fit onto my motor. I will have to turn down my shaft to 11.8, and shorten it and re-mill the keyway. I am in highschool so i can machine for free! but the dealbreaker- is this even a good, reliable trans?
Click to expand...
 
Last edited:
i really like that exhaust pipe and i bet it works like a flowmaster. best part is it will confuse alot of people.
 
I was afraid of that. Ill look for used trans, I don't have alot to spend. That pipe made me laugh too. I might cut it in the Middle to make it a horn.
 
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