Thread on thread...

[solomon]

i would easily get carried away if i was building a bike....

 

[devino246]

If you want to do a belt tensioner, heres how it works

While the engine is idling, the belt is loose. When you want to take off, just rev the engine a little and release the belt tensioner(i just realized i left a spring off the drawing). A spring pulls the tensioner against the slack side of the belt and pulls it tight.

 

[Carney]

If you want to do a belt tensioner, heres how it works

While the engine is idling, the belt is loose. When you want to take off, just rev the engine a little and release the belt tensioner(i just realized i left a spring off the drawing). A spring pulls the tensioner against the slack side of the belt and pulls it tight.

Oh sweet, thanks for the drawing. But my question is, if the spring is pulling up the tensioner how will i make it stay down (toggle) when i want to "engage clutch"?

 

[Doc Sprocket]

What exactly is the ratio of the reduction unit? You can postulate about pulley size 'till the cows come, but it means nothing until you have some working numbers. As long as it's no deeper than about 6:1 you should be okay.

 

[Carney]

What exactly is the ratio of the reduction unit? You can postulate about pulley size 'till the cows come, but it means nothing until you have some working numbers. As long as it's no deeper than about 6:1 you should be okay.

Yea im going to check it out tomorrow.

 

[devino246]

Oh sweet, thanks for the drawing. But my question is, if the spring is pulling up the tensioner how will i make it stay down (toggle) when i want to "engage clutch"?

The spring pulls the tensioner up engaging the clutch all the time. Pulling the clutch lever actually disengages the clutch, just like a car or motorcycle. For this reason you would need some way to keep the tensioner disengaged, although it wouldnt be that hard. Im hopefully going to be doing a similar setup on my kart in the next month.

 

[Carney]

Turns out the reduction unit it 6:1. Just need to find out the gear ratio to reverse it.

Heres some pictures of the engine:

 

[solomon]

man, you got screwed on that motor. I would have tried to return it, and if he didn't take it, it would have been through his window at 2:00 AM

 

[Kaptain Krunch]

what size tires do you plan on using? 6:1 is a pretty good ratio for around 16" tires. You can easily work with that, just do the belt tensioner, better than a centrifugal clutch IMO.

 

[Carney]

what size tires do you plan on using? 6:1 is a pretty good ratio for around 16" tires. You can easily work with that, just do the belt tensioner, better than a centrifugal clutch IMO.

Yea, i actually like the belt tensioner idea. It sounds like fun, makes the riding more interesting. The tires that i have to work with are pocket bike tires.
Does anyone know how to figure out the right gear ratio with the 6:1 reduction?

 

[Kaptain Krunch]

When dealing with multiple ratios, just multiply.

For example, 6:1 reduction box, with a 2:1 ratio between that and axle, 6:1x2:1=12:1

You need to know the diameter of the pocket bike tires, but im assuming its around 10" or 12", you can probably gear it a little higher than 6:1, so you may want to run a 1:1.5 ratio between the reduction box and axle, which would give you a 4:1 overall between engine and axle.

 

[Carney]

When dealing with multiple ratios, just multiply.

For example, 6:1 reduction box, with a 2:1 ratio between that and axle, 6:1x2:1=12:1

You need to know the diameter of the pocket bike tires, but im assuming its around 10" or 12", you can probably gear it a little higher than 6:1, so you may want to run a 1:1.5 ratio between the reduction box and axle, which would give you a 4:1 overall between engine and axle.

Sounds good. Thank you so much.

 

[Carney]

To keep the tensioner bar disengaged or engaged Im just going to use the same concept of a bicycle kickstand. The spring is gonna be hard to move so ima make it like a pedal so i can operate it with my foot. At least that is what i intend to do...

 

[Kaptain Krunch]

Just use a spring to keep tension (strong one), and then when you press the clutch pedal it will will on the tensioner and release tension. Kickstand idea is ok, but what happens if (when) the belt stretches (which over time it will).