Help with my Chainsaw bike

[MisterSteve124]

The engine is 42ccs and I'm gonna use a jackshaft to hopefully get a gear ratio of atleast 14:1 right now I have 2.75:1 lol.

[jrrdw]

The only way a jack shaft is going to change the ratio is if you use 2 chains and 2 different size sprockets on each end of the shaft. Other wise it's a idler gear shaft.

[ammosmoke]

The smaller the gear on the engine, the easier it is going to be for it to move. And the wheel gear should be one of the bigger ones. Think of it like a torque wrench. What is easier to turn, a small one or a big one? Well, a big one of course, more torque. What is easier to twist? A small bottle cap or a big one? A small one, less resistance.

Next time when you are riding a mountain bike, look at the gears while shifting. The higher gears are the small ones. A small one will turn many times faster than a big one, but it is harder because there is less torque. A larger drive gear will spin the wheel gear faster because there is more teeth, but it is harder to turn because there is more resistance.

Get it?

[MisterSteve124]

Yeah I know that's what I'm going to do. Try and get like a jackshaft with like a 10 tooth sprocket and a 30tooth or the biggest difference I can find.

[jrrdw]

Here, a wide selection to feast your eyes on! You can even get blanks and drill your own center holes and bolt pattern.

[MisterSteve124]

I'm using two jackshafts with gears in order starting with drive and ending with the rear of: 13, 20, 8, 20, 8, 36 for a total gear ratio of 19:1 . Now I have 2.76:1 so huge difference. With that set up I won't burn out my clutch I will have lots of torque and go around 40mph! I'll post the results once I get it all installed and working.

[dewey-1]

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[MisterSteve124]

Yeah you are right that was the calculation I did with a 13 drive sprocket and a 22 tooth sprocket on the jackshaft. I will be able to tension them and they are all out of the way from anything since they are above the rear tire. But the drive sprocket will have a chain gaurd and I'm sure I'll fabricate one for the others once I get it all installed.