Anyone have any info on kart transmissions
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mckutzy
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This is a long topic(or short???) here that hasent been really answered yet as it isn't really easy to construct a transmission so as to be readily shifted on the fly, without any good thinking, some money and probably a good amount of time to make one.
If you look at the DBR crew and there new clutch they made, It's been god knows how long a clutch that is manual actuated, and that's just with a single speed. They spent a long time money and effort to do that.
So in conclusion, a trans is going to be that much more difficult to do by ones self.
Don't mean to come off like an a$$, but this is reality.... Sadly... I'll cry with you(maybe not but you understand)
I'd lik to have a cheap one too.
If you look at the DBR crew and there new clutch they made, It's been god knows how long a clutch that is manual actuated, and that's just with a single speed. They spent a long time money and effort to do that.
So in conclusion, a trans is going to be that much more difficult to do by ones self.
Don't mean to come off like an a$$, but this is reality.... Sadly... I'll cry with you(maybe not but you understand)
I'd lik to have a cheap one too.
I think every single one of us here would like to get hands on a cheap multispeed (5 or 6) gearbox for an industrial engine.
Some with, some without reverse, some for heavier duty some for lighter duty..
but basically that's what we all would like to play around with.
The thing is, it's expensive..
it's cheaper to get a motorbike engine (pitbikes due to the smaller size..) with the gearbox already in place than to even think about making one
'sid
mckutzy
Well-known member
I have been thinking on a few Ideas about transmission's for a few years now, they still basically still come back to a few basic points. They have gears. Gears arent easy to make, they are hardened material, need to be lubricated well, and dont take well to imprecise dimensions. All these are hard for us DIY guys to hombrew up a bunch of gearsets to make a kickin ride..... kick.
If determined to do so, I reckon you take a look at what is called a dog clutch. Used in alot of motorcycles already, can be made to be a litlle imprecise it might be able to cobble up a working trans... but it will most likely have chains attached instead of actual meshing gears.
With that, size goes up, and if one ring throws a chain, potentially the whole box will be just that.. a box of parts(mainly bits of metal)
If determined to do so, I reckon you take a look at what is called a dog clutch. Used in alot of motorcycles already, can be made to be a litlle imprecise it might be able to cobble up a working trans... but it will most likely have chains attached instead of actual meshing gears.
With that, size goes up, and if one ring throws a chain, potentially the whole box will be just that.. a box of parts(mainly bits of metal)
Well, fair point.
But I don't think it's just the gears, you can (well I can.. so I'm sure you could too) buy hardened steel gears off the shelf...
I wouldn't bother;
I'd directly grab a set of motorbike gearshafts you can find on ebay for more or less a few bucks.
you can have a complete set of gears aligned on two shafts for a six speed gearbox for let's say $100,
the thing is, the cam, lever and fork to move them is another $100,
and now one would need a box to mount them in..
that alone will take some tries to do it right and let's say at least another $100 (material, nuts, bolts and gaskets only)
that's $300 the very least for basically the same 6speed gearbox you can buy used with an attached cylinder, carb and flywheel for not much more than that in an over all smaller package.
So, as much as I would want one of those, I know it's not exactly a bright idea to make one (as if I could)
'sid
But I don't think it's just the gears, you can (well I can.. so I'm sure you could too) buy hardened steel gears off the shelf...
I wouldn't bother;
I'd directly grab a set of motorbike gearshafts you can find on ebay for more or less a few bucks.
you can have a complete set of gears aligned on two shafts for a six speed gearbox for let's say $100,
the thing is, the cam, lever and fork to move them is another $100,
and now one would need a box to mount them in..
that alone will take some tries to do it right and let's say at least another $100 (material, nuts, bolts and gaskets only)
that's $300 the very least for basically the same 6speed gearbox you can buy used with an attached cylinder, carb and flywheel for not much more than that in an over all smaller package.
So, as much as I would want one of those, I know it's not exactly a bright idea to make one (as if I could
)'sid
jogfrogjog
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can you put another engine up to a bike shifter?
mckutzy
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What's a bike shifter? Like what do you mean?
jogfrogjog
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Like a 6speed from a pit bike or auto cross or even a road bike (motorcycle), or even a shifter box from a shifter kart if it can be used with other engines. I have a kohler magnum 18 with a 2 seater kart that i was thinking either a 40 series torq verter or if I could a shifter box.
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let's see one...
I know there is one custom made external box... all others are part of the engine
(on every post WWII motorbike or shifter kart)
'sid
I know there is one custom made external box... all others are part of the engine
(on every post WWII motorbike or shifter kart)
'sid
mckutzy
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Are you talking about a trans from a big twin Harley?
jogfrogjog
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From anything that will easily bolt up to 1" output shaft motor.
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yes.. nice.. if you find something that does, let us know;
since we haven't yet.
'sid
since we haven't yet.
'sid
mckutzy
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Well not cheap anyways, last trans I saw was $3k CAD. Used.......
If you did that you might as well use a rearend out of a riding lawnmower and just figure out how to flip the pulley sideways then you got 3 plus reverse.
WAIT A MINUTE HERE ! ..............................
why cant you turn the whole rearend where the pulley is sideways and just attach it to the motor with the motor sideways and just use 2 u-joints like a mini driveshaft ? And getting rid of the big pulley and going to the driveshaft would also add alot more mph than on the mower originally. And also you could use a normal kart clutch attached to a jackshaft so you could shift it.
Only problem i got is i dont know whether you would have 3 forward gears and 1 reverse, or 1 forward gear and 3 reverse gears. lol
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mckutzy
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Would the transmission handle the direct torque from the motor.
I ask, as they originally have a belt system for the drive, I'm guessing there is a bit of slip. Would seem like a bit of protection thought of there.
I ask, as they originally have a belt system for the drive, I'm guessing there is a bit of slip. Would seem like a bit of protection thought of there.
I would think it would be fine cause the lawnmower engines are not any bigger on hp than what we are using for go karts. And i just found the solution to NOT having too flip it sideways...................
Its off of a Craftsman GT6000 Riding Mower. (sorry i forgot)
Its off of a Craftsman GT6000 Riding Mower. (sorry i forgot)
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that's nice... but as far as I know mower transmissions aren't really a big fan of rpm..
So you might end up destroying a mower gearbox with a much smaller engine just because you geared for speed not torque.
*shrugs*
I'd love to see working though.. so if you can, try it and let us know
'sid
PS what's the model of that mower trans? Maybe one can find a cheap source on CL instead of ebay.
So you might end up destroying a mower gearbox with a much smaller engine just because you geared for speed not torque.
*shrugs*
I'd love to see working though.. so if you can, try it and let us know
'sid
PS what's the model of that mower trans? Maybe one can find a cheap source on CL instead of ebay.
firemanjim
Just kartin' around....
Yeah, what did that come out of? I like it.....
AceEngineer
New member
I'll chime in and agree with itsid, making a gear box can get real expensive fast even if you can do your own machining. I was faced with the same problem on the shifter I'm building and I went the motorcycle engine route. Since I was starting with an existing frame, the only way the motor fit was backwards. Big problem!, 5 speeds backwards. Solution: a single gear set to reverse the rotation of the output. I set about designing and building a 1:1 gearbox. I found a set of hardened gears in the Boston Gear catalog, and they came to about $120 for the set. These gears were sized for the correct torque and horsepower at the existing transmission output. I machined two housing halves and the shafts. The shafts run in tapered roller bearings and the gearbox is sealed with some shaft seals I bought so it can run in an oil bath. Total cash investment about $180 including the bearings and the aluminum billet I started with plus about 6 hours on a Bridgeport (cost not included). This is just for a single gear set, not a transmission no shifting involved. Building a multispeed transmission would be way too expensive. You should be able to buy a bike engine with transmission for a lot less than you can build a transmission. I am a retired mechanical engineer and I still owned a machine shop when I built this gearbox, so I doubt anybody could do something like this cheaper.
AceEngineer
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