2 speed, how does it work?
Illustrated How It Works: the Two Types of 2-Speed Jackshaft Setups
I originally illustrated from memory the Sears 2-speed minibike I had at age 14. Courtesy of OldMiniBikes members my knowledge was expanded to realize the Sears was the Comet setup.
Other members soon contributed and it was explained how the Fairbanks-Morse 2-speed differs, is easier to build, and is better at keeping chain lubricant out of the jackshaft clutch. :thumbsup:
Each phase is illustrated. The F-M illustration includes a side-by-side comparison with the Comet setup on page 4.
Jon
I originally illustrated from memory the Sears 2-speed minibike I had at age 14. Courtesy of OldMiniBikes members my knowledge was expanded to realize the Sears was the Comet setup.
Other members soon contributed and it was explained how the Fairbanks-Morse 2-speed differs, is easier to build, and is better at keeping chain lubricant out of the jackshaft clutch. :thumbsup:
Each phase is illustrated. The F-M illustration includes a side-by-side comparison with the Comet setup on page 4.
Jon
Jackshaft, Gear Ratio, and Speed Calculators
The Fairbanks-Morse and Comet need a dual sprocket clutch like this one from OldMiniBikes on the engine.
The Fairbanks-Morse uses a standard clutch on the jackshaft.
The Comet requires a hard-to-find jackshaft clutch that fixes the bell to the shaft, and floats the clutch shoes on a bearing.
You can easily experiment with gear ratios, tire sizes, and RPM's to see what various speeds would be happening.
If you have Excel, download these spreadsheets, put in your numbers, and experiment freely:
No Jackshaft
2-Speed Jackshaft
Plain Jackshaft
No Excel? Don't "get" spreadsheets? Easily use them online, no software needed:
No Jackshaft
2-Speed Jackshaft
Plain Jackshaft
Jon
The Fairbanks-Morse and Comet need a dual sprocket clutch like this one from OldMiniBikes on the engine.
The Fairbanks-Morse uses a standard clutch on the jackshaft.
The Comet requires a hard-to-find jackshaft clutch that fixes the bell to the shaft, and floats the clutch shoes on a bearing.
You can easily experiment with gear ratios, tire sizes, and RPM's to see what various speeds would be happening.
If you have Excel, download these spreadsheets, put in your numbers, and experiment freely:
No Jackshaft
2-Speed Jackshaft
Plain Jackshaft
No Excel? Don't "get" spreadsheets? Easily use them online, no software needed:
No Jackshaft
2-Speed Jackshaft
Plain Jackshaft
Jon
The online Plain Jackshaft link connects to the No Jackshaft spreadsheet. My goof.
The above bolded link is correct.
The above bolded link is correct.
You can buy a one-way bearing clutch and press it into a sprocket.
For example https://www.mcmaster.com/products/one-way-clutches/
Another example https://www.formsprag.com/products/General-Purpose-Clutches/Bearing-Envelope-Design/CSK-Series
There are #35 sprockets with one-way clutches, additional looking might turn up more results.
For example this is current in November of 2023:
https://www.daytonsuperiorproducts.com/one-way-sprocket-clutch.html
Hope that helps!
For example https://www.mcmaster.com/products/one-way-clutches/
Another example https://www.formsprag.com/products/General-Purpose-Clutches/Bearing-Envelope-Design/CSK-Series
There are #35 sprockets with one-way clutches, additional looking might turn up more results.
For example this is current in November of 2023:
https://www.daytonsuperiorproducts.com/one-way-sprocket-clutch.html
Hope that helps!
