Jackshaft design

[SharpTJ]

I have stuffed 420cc Predator into a old vortex frame, so I am a little cramped for space. I threw this on there just to get the wheels turning, and as you can see, it twisted up pretty good (and quickly lol).

Just looking for some ideas for a solid jackshaft mount

 

[KartFab]

Your drive unit is on backwards.

I've made Jackshaft assemblies with great success on a gx390.
This is on a dingo, u can see in video
https://youtu.be/109rqjxcjSA

Same thing here but smaller kart.
https://youtu.be/54aJQ3_MGx4

Idea is get about 2" width 3/16" bar for sides, and 3/16" plate for top and bottom. Weld 11 ga tubing/pipe for Jackshaft holder. I just used 2$ 5/8" bearings and 5/8" keyed rod, but you could use the cast bearing hangars as they are heavy duty.

Also I used 7/16" bolts to mount engine to plate, and 3/8" bolts to mount Jackshaft assembly to kart.

 

[gman3850]

or you can check out this one which no welding is involved

X1 - 6x3 3/16 13" long 20$
X2 - 3/4 pillow flange bearing Amazon 9$ea
X1 - 3/4 14" jackshaft ombwarehouse 14$

the legth between driver and driven is 9 3/8

 

[SharpTJ]

I guess that backwards driver is why it bent the jackshaft mount.... just to be sure, with the comet 40, the driven is mounted with spring in and the driver needs to have the moving part outside...right?

 

[gman3850]

no that jackshaft just isnt designed to pull that much torque

 

[Jrgunn5150]

I guess that backwards driver is why it bent the jackshaft mount.... just to be sure, with the comet 40, the driven is mounted with spring in and the driver needs to have the moving part outside...right?

Correct, I have the same Kart, my spring is sitting outside.

I have to agree though, the metal it's made out of isn't super thick, you may need to fab a new one. I'm glad you posted this, as I was considering the same motor for later lol.

 

[SharpTJ]

I flipped the driver around and of course had all kinds of alignment and space issues. To get the driver and driven close, i had to move the chain and sprockets the other side of the motor. Also, found my Jackshaft is bent, so I have another on order.

So hopefully, when I get it my buddy to weld it up Thursday...maybe I (er, my kids)will be in business

 

[Jrgunn5150]

Good luck, mine is a lot of fun, and faster than you want to go in a go kart with the Predator 212 lol.

 

[SharpTJ]

Good luck, mine is a lot of fun, and faster than you want to go in a go kart with the Predator 212 lol.

What gear ratio don you use? ..I'm thinking about 60/12

 

[Jrgunn5150]

Whatever the factory ratio is is what I have, I haven't bothered counting teeth yet. I think I read it was 60/10 but I'm not sure.

I swapped the non-running Subaru for a 212 with a jet kit, intake, header, and governor removed, rebuilt the clutch, and hammered down.

I've only driven it up and down my street a bit, but, live at the bottom of a pretty steep hill, and I weigh 260 lb's. Up hill I can pull 32 mph, down hill, I lifted at 50, it has a lot of bump steer lol.

 

[SharpTJ]

Whatever the factory ratio is is what I have, I haven't bothered counting teeth yet. I think I read it was 60/10 but I'm not sure.

I swapped the non-running Subaru for a 212 with a jet kit, intake, header, and governor removed, rebuilt the clutch, and hammered down.

I've only driven it up and down my street a bit, but, live at the bottom of a pretty steep hill, and I weigh 260 lb's. Up hill I can pull 32 mph, down hill, I lifted at 50, it has a lot of bump steer lol.

Lol, well, I'll have to govern this down for a 7 year old then until it's my turn to play...factory is 9/60'

 

[Jrgunn5150]

I drilled the factory floorboard for some threaded rod and tacked a nut to it to make a throttle stop so kids can ride it. Mine isn't slow at all, I'm sure your's will be a rocket.