Reverse Gearbox

[Stratus]

Are there any cheap reverse gearbox's?
I know of the comet one but its 250$ that to much and i need it desperatly.

 

[redsox985]

An opposed belt tensioner? That's about the cheapest thing I can think of. Or an electric motor and switch the + and -.

 

[Stratus]

could this be a good gearbox
http://http://cgi.ebay.com/ebaymotors/GEAR-BOX-TRANSMISSION-GO-KART-250cc-ATV-LIFAN-GY6-_W0QQcmdZViewItemQQhashZitem230b5adad3QQitemZ150514358995QQptZLHQ5fDefaultDomainQ5f100

 

[redsox985]

It didn't work for me. Are you signed in to Ebay by chance?

 

[Stratus]

do you mean the ebay link?
if so here it is: http://cgi.ebay.com/ebaymotors/GEAR-BOX-TRANSMISSION-GO-KART-250cc-ATV-LIFAN-GY6-_W0QQcmdZViewItemQQhashZitem23079a9bd0QQitemZ150451428304QQptZLHQ5fDefaultDomainQ5f100
And another one i found even though i doubt it works:http://cgi.ebay.com/ebaymotors/Hensim-ATV-110cc-China-Chinese-Transmission-Drive-Gear_W0QQcmdZViewItemQQ_trkparmsZalgoQ3dLVIQ26ituQ3dUCIQ26otnQ3d5Q26poQ3dLVIQ26psQ3d63Q26clkidQ3d4705793594285292718QQ_trksidZp5197Q2em7QQcategoryZ43972QQitemZ200505984962

 

[Stratus]

Im 15 and i dont have an ebay acount, i have to use my parents.

 

[redsox985]

I don't know much about gearboxes other than that the Comet one is the most common on karts. I believe your two links were to parts of a shifter transmission.

 

[Stratus]

what did you mean about the opposed belt tensioner, what is that?

thanks

 

[modelengineer]

It's a belt tensioner clutch with the belt twisted 180 degrees so the pulleys spin in opposite directions. Then you have another belt with clutch which is not twisted, for forwards.

 

[r97]

i don't think the opposed belt tensioner would work horribly well, it would work, but not in the mud, may have trouble with big karts, and it would prob wear down one side of the belt, or the belt would often come off. you could make one, find the 2-speed tranny that was built on here, make one just like that except put it in oil, and replace on of the sets of sprockets with some gears.

 

[sideways]

i don't think the opposed belt tensioner would work horribly well, it would work, but not in the mud, may have trouble with big karts, and it would prob wear down one side of the belt, or the belt would often come off. you could make one, find the 2-speed tranny that was built on here, make one just like that except put it in oil, and replace on of the sets of sprockets with some gears.

How would you tension a twisted belt anyway?

Hayden

 

[fowler]

by moving either the nigine or driven pully backward

 

[sideways]

by moving either the nigine or driven pully backward

Easier said than done, it would tension both pulleys too. You don't want the forward gear pulley too slack.

Hayden

 

[fowler]

think of how a grain auger works (assuming u have one)
the forward can be acheived though a tensoin arm and the reverse by pulling the engine

also because twisting a belt makes it shorter, pulling the engine wouldnt tension both belts

 

[Doc Sprocket]

Let me ask- Why do you "desperately need" reverse? Honestly, I don't really miss it. All you have to do is not stop with your nose up to an object! Heck- if you've got enough power, you can crank the wheels, stab the throttle and spin the kart around in spaces much smaller than your turning radius. I think in three years, I've had to get out and push my kart back away from something once.

...Just a thought...

 

[redsox985]

By opposed belt tensioner, I meant like what that guy built into his mini Sherman. I'm not sure if anyone remembers it but here's how I remember it. Motor gear to jackshaft 1, a cog and pully on the jackshaft 1, the cog spins a cog on jackshaft 2 that also has a pully. From each pully on JS 1&2, a belt goes to a pully on the axle. Then, since JS 1&2 are spinning in opposite directions, you tension the proper belt to apply the proper spin to the axle giving you forward and reverse. It's not as simple as a gearbox or a motor with reverse, but it is cheaper.

 

[r97]

only way i can think a twisted belt would work is with a really long, not too wide, v belt with a lot of idlers. tensioning wouldn't be easy. my idea, i think is simple, and affective, might be cost more than the one on ebay, but you get to make it which means you know its good quality, and you can fix it with your eyes closed! its this except in an oil bath, and replacing one of the chain/sprocket combos, with two gears, if you use t as reverse it also almost eliminates the problem of not being able to shift on the go because you would be stopped, for the most part i don't think reverse is a necessity(unless you have a big kart), but its a fun project, and fun to have.


p.s. i'm not sure if the $10 one is what your looking for

 

[porsche930dude]

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=260687845862

 

[r97]

only problem is its also a ragb, unless he is using a mower engine...... not sure how much power it can handle.

 

[gokart14]

Let me ask- Why do you "desperately need" reverse? Honestly, I don't really miss it. All you have to do is not stop with your nose up to an object! Heck- if you've got enough power, you can crank the wheels, stab the throttle and spin the kart around in spaces much smaller than your turning radius. I think in three years, I've had to get out and push my kart back away from something once.

...Just a thought...