stuck sprocket on a old kids bike that is held on at the crank?

[TheSignGuy]

Found a nice 35 tooth sprocket off a junk kids bicycle but the screw ring is stuck that holds the peddle to the crank tried a mallet a hammer and a screw driver won't come off rehearing to 35-24, (Front to rear).


Any solutions will have to be custom punched to fit my front assemblies or atleast to weld on.

 

[maniac57]

cut the nut with a dremel or other thin cut off wheel.
It will release once you get close to parting it.

Usually works.

 

[TheSignGuy]

cut the nut with a dremel or other thin cut off wheel.
It will release once you get close to parting it.

Usually works.

True but in specifics I'm having an issue with gearing I know not to go to big on gearing.

For what I want to gear in would seem like it would lack power uphill


So here is the break down for my current gearing I have 3 options


current gearing: 13 tooth front sprocket x 24 tooth rear sprocket = 15.5mph top speed. (Top end screamer)


first gearing option: 13 tooth front sprocket x 35 tooth rear sprocket = 18.8mph

second gearing option: 13 tooth front sprocket x 40 tooth rear sprocket 20.6 mph

third gearing option 13 tooth front sprocket x 50 tooth rear sprocket = 25.8mph


Basically the issue here is unless I got up to 60 tooth in the rear which I have limited space for a sprocket that big, plus I feel I would slugg on hills from that gear size 50 is as high as I can get at the time and these ratios the current is accurate with my weight on it.

But the downfall is its a 49cc so a big bore kit can conquer the differance in the speed with a lower tooth ratio.

 

[kevyleven007]

Dang. Too bad a 60 tooth wont fit. maybe you could try a 40?

 

[TheSignGuy]

Dang. Too bad a 60 tooth wont fit. maybe you could try a 40?

Either way if I threw in a 60 would have to be welded on a 40 would work problem is I wish I could find a axle hub bolt for schwinn with the sprocket built in at 40-60

 

[maniac57]

Your math is wrong.
A smaller rear sprocket will RAISE top speed if front stays same.
Not like you have it

 

[TheSignGuy]

Your math is wrong.
A smaller rear sprocket will RAISE top speed if front stays same.
Not like you have it

​

Was thinking more long the lines of this speed ratio 18- 22 set up 18 being in the front for longer flat level for the gear ratio,


18x 20÷20 = 1

​

9.8mph

Right now it's 24 to 13 baby teether pretty much 15.5mph

This is ambrionic to what it could do.

 

[Saddletramp1200]

With a 66cc & a 38 T sprocket I get about 18 mph. In the bed of a pickup It gets 75 or so.

 

[TheSignGuy]

With a 66cc & a 38 T sprocket I get about 18 mph. In the bed of a pickup It gets 75 or so.

FS FRONT SPROCKER X RS= FRONT SPROCKET ÷ TD = TIRE DIAMETER= SPEED


SO CURRENT IS WRITTEN LIKE THIS

FS 13 X RS 24÷ TD 20 = 15.6 MPH actual speed is 15.5mph which is a .1 losage in mechanical conversion theory.

There are two chains one in the cvt cover and one for to drive the rear tire.

The goal is to not exceed moped laws of 30 mph so I want to be slightly underneath that law.

Initial thought is FS18 X 24÷20 = 21.6MPH - .1 = 21.5 MPH


MY ACTUAL TIRE HEIGHT IS 20 X 1 1/4 GIVEN THEORY IN ADDITION TO LOSSAGE..

upping teeth in the front only would still provide a better gear ratio


Removes that screaming engine feeling, but still provides full power load without to much loss of torque.

19 tooth is as big as the front sprocket can get without customization. So an 18 should do very well toward top speed.


I may also need to rejett as past 3/4 throttle it boggs out. The pikot circuit is fine as it fires the engine first kick everytime have not changed plugs yet but I have cleaned mine and verified it stays a nice coffee brown but runs lean after 3/4 turn meaning main jets to small also plan on removing the redneck gy6 China exhaust and welding on my extra moped muffler which should be a lot quieter on roads without roaring uo the block like a teenager when I have to hit the sidewalks. In town traffic hour.