Gearing/jackshaft question

[wheels]

Hello all,

For my next project, i will be using a jackshaft... Of course, i'm a newbie to jackshafts. so, please forgive this possibly goofy question.

i'm wanting to change the sprockets around a bit. for example, instead of having the largest tooth sprocket on the live axle... would it be ok to put the larger sprocket on the input side of jackshaft?

the motor has a 520 chain and roughly 18-20hp, if that makes a difference.

my goal is ground clearance... if i can get another 3 or 4 inches of clearance, it would be great.

any thoughts or experience with this, good or bad?

 

[landuse]

What are the tooth counts of the sprockets that you are going to use? Changing the sprockets will usually change gearing, but it depends on the combination of sprockets you are moving.

On my minibike, I have a 16T clutch, a 38T JS input, 12T JS output, and a 57T on the back wheel (which would be like the large sprocket on your live axle). My ratio is as follows:

(38/16)*(57/12) = 11.28:1

If I change things around by swapping the 38 and 57
(57/16)*(38/12) = 11.28:1

So you get the same ratio. This means that you would be able to change the JS input with your live axle sprocket. For me the size of the 57T would not have made that practical for me, but for you on a kart, size might not matter.

Here is a pic of my jackshaft. In the pic of the unpainted bike, I still had to swap my JS sprockets around because they were on the wrong side. The larger sprocket should be on the JS input side, like you see in the pic of the painted bike

 

[wheels]

18/38 is the gearing and i have 22inch tires(i'll have to go in the shop and physically check both again, to make sure).

I'm going down to an 18inch tire though.

and the Kart will be 400-500 lbs when finished.

so, i still have to figure out the gearing that i want...

thanks for the input Landuse, i appreciate it.

 

[wheels]

figure i'll go ahead and ask another question about the jackshaft idea while i'm at it....

with the above question, i was thinking of mounting my engine beside me. i would actually like to mount it behind me though... which leads to a different jackshaft setup:

having two jackshafts. One input output going down and out from the engine... a chain going from that Jackshaft to another at the base of the swingarm... and then, of course... a chain going from that jackshaft to the axle.

i'm wondering how much power i'll lose... and if the setup will hold up or be worth it. I am trying to avoid IRS, CV's, etc.