Motorcycle gearbox... Usable on a HF212

[Half-breeder]

I was sittin here wonderin if the 'gearbox' out of a dirt/street bike work on my kart? Only askin cause i dont know squat bout bike transmissons.

 

[J_Walker]

Depends from what bike, dirtbike I doubt it. I know some Harleys have external gearboxes. but MOST street bikes have internal gearboxes, and it would be 3x the price to convert them, instead of just using the whole engine..

aprilia engine

 

[Half-breeder]

Ahh kk. So 'if' i were to get a motor n tranny... What would be a good size to get? Theres a motorcycle graveyard down the road. Only lookin for something in the 10hp range... just dont know the equivalency in cc's asfar as motorcyles...

 

[machinist@large]

I could be wrong, but from what I've seen and read over the years the only Mfr that still uses a divorced transmission is Harley Davidson, and they only use them on the Big Twins; the Sportster line has always used an integrated set up.

On the plus side, there is a lot of aftermarket support for these bikes, including complete stand alone tranny's so there are more than a few floating around. I wouldn't term it a plug & play though.

One of the reasons the market developed the Centripetal style clutch and the torque converter style transmission was because of calls for simplicity and ease of installation and use; kind of the opposite of what you seem to have in mind here.....

 

[OzFab]

There's no direct correlation between CCs & HP...

It is possible to convert an engine/gearbox combo, there's just a lot of work involved & involves the sacrifice of the engine. If you happen to find a unit with a damaged/ dead engine, you run the risk of the gearbox being damaged or otherwise unusable...

 

[firemanjim]

A decent running 125cc 2stroke or 4 stroke puts out near 10 hp..... near...... I know from personal experience that a china 125cc engine on a yard kart is TONS OF FUN...... even a 80cc would be cool. Its the gear box that makes the difference....

 

[mckutzy]

I would wonder what would be(if such a thing, but im sure there is) the minimum horsepower required to run a trans from a harley?

Like is a typical 6.5hp clone going to die from just not even able to overcome the grip of the clutch to start moving the machine?

 

[firemanjim]

I dont think a 6.5 would cut it, but a 11/13 hp should work nicely, with the right gearing. Even better,big twin industrial honda ,18/21hp would be on par for such a build......

 

[Half-breeder]

.... im 'trying' to keep things somewhat simple. 125cc 2stroke sounds 'simple'. Trying to get the higher rpms, faster revs... plus the sound, and if I can get gears as well, that would be awesome! Theres just something bout the weedeater sound, on a kart, that turns heads 'curiously'... where as round here the lawnmower 'sound' turns heads aswell, but annoyingly.

 

[firemanjim]

A 4 stroke works just as well and almost no maintaining it... I prefer 4 over 2 for normal everyday play, but 2 stroke if its just GOT TO BE FAST. ....

 

[J_Walker]

Get a honda rebel engine. they are like 16HP. really good engines for gokarts. Air cooled, two valves a cylinder, straight twin, Overhead camshaft.

looking on ebay. anywhere from 100-300 dollar range, depending on the work needed. lots of them need the carbs though it seems..

 

[icebox187]

there are several european companies that had "pre unit" transmissions. Royal enfield and triumph are but 2 of them that I know of. You can generally pick one up on ebay that needs minor work for 200-400 bucks.

 

[rocketkart]

you want a gearbox/transmissions just get this http://www.mfgsupply.com/gomini/gominiaxles/gominiaxlesgearbox/218390a.html

 

[itsid]

you want a gearbox/transmissions just get this http://www.mfgsupply.com/gomini/gominiaxles/gominiaxlesgearbox/218390a.html

just forward and reverse.. not exactly a motorbike six-speed replacement, is it??

'sid

Oh I mentioned (in some other thread) that thee was a company converting motorbike six speeds to use with a kart..

Unfortunately that was my mistake,
I was referring to this nice thing here:

And although it's a six speed transmission for a go kart alright,
it's not made BY Hirth (my mistake)
but made FOR a hirth engine (this one)
by Sven Weinig
So yeah, almost right

But I guess, at least a few of our members can do the same
(Not me unfortunately)

Many german pre-war bikes (such as Victoria) had external gearboxes for midsized engines (200-350 cc);
I think many other manufacturers around the globe had too;
so maybe you can get hold of one of those.

'sid