Sprocket problem!

[Minibikeman123]

Hi
New here. I am currently building a mini bike but I need help with gear ratios and what number of teeth I should put on each sprocket.
I need your help to determine what number of teeth I should put on my sprockets.

Please can you suggest a number of teeth for each of the following sprockets:
Clutch sprocket:
Jack shaft sprocket 1:
Jackshaft sprocket 2:
Wheel sprocket: (set at) 54 teeth
I have written all the info in the picture. I would like very good acceleration and torque ( but not enough to throw me off the bike (rider weight in pic)) and a top speed around 25 to 30 mph. The engine is a 196cc 6.5hp.

Thanks a lot
Henry

 

[OND]

Welcome aboard Minibikeman ! If it was me I would be looking for a total gear ratio of about 6.50, with that in mind clutch 12 tooth, input jack shaft 18 tooth, jack shaft out put 14 and rear sprocket at 60 teeth...that would give you about a 6.43 total gear ratio. Here is a calculator you can use.
Jackshaft Ratio Calculator

Burris Racing Jackshaft Calculator

 

[Minibikeman123]

Great thanks for the quick reply
Would this setup be good for off road?
Sorry to be difficult but i received the back sprocket ( 54 teeth) with the wheel. Should I still swap it for the 60?

 

[buckeye]

Henry
Welcome to OldMiniBikes.
What a great explanation of what you are looking for.
Someone will know.

 

[OND]

If you have a 12 tooth driver on your clutch, you could go 19 on the input and 13 on the output with a 54 tooth rear sprocket and end up with a 6.58 total ratio.

 

[minibikin']

A 54T is normally #41 chain. Do you the pitch of that sprocket?


Sent from my Texas Instruments Speak and Spell...[emoji2]

 

[Minibikeman123]

Thanks for the help ond I will go with that
The 54t sprocket has a 8mm pitch

 

[Havasu Dave]

Henry,

In case any of the posted links do not work, here are links to jack shaft calculators as well:

On Line Version of Jack Shaft Calculator

MS EXCEL version of Jack Shaft Calculator.

Refer to this link if the above isn't working. Pretty neat programs.

 

[Minibikeman123]

thanks a lot havasu dave and everyone else.
for my rear wheel sprocket it has an 8mm pitch and it has 54T. could somebody tell me what #?? chain I should use
thanks again
henry

 

[CarPlayLB]

8mm chain does not crossover to any U.S. common chain. Your wheel probably came off some sort of pocket bike. It is smaller than the #35 chain which is common to minibikes here. Good luck! Maybe swap out that rear sprocket!