Our First Go Kart build. [Alternate title: Noob questions]

[silveravnt]

Hello All from Oklahoma.

So far all we have done is to buy a suzuki quad engine and trans and draw a few sketches.

I got the quad because my son wants a go kart with gears he can shift. The quad has that, no clutch lever, it's a good brand and there is a bonus (reverse). It also came with wiring for headlights and electric start. The quad had been wrecked but ran.

Searching the internet, it seems not many people have built a two seat kart with a quad motor. They are usually 1 seat beside the motor since the output sprocket of the motor is at the left rear and the chain pretty much needs to go rearward.

For a minute I considered a front engine design but I am not sure of a safe and reliable way to get power to the rear wheels. also the fuel would have to be pumped to the carb.

Our idea is to use a rear mounted jackshaft so we can mount the motor more over the rear axle and so we can gear it down. The transmission has 5 speeds and I think at least at first I want to limit the top speed.

Another hurdle with our engine is that the output sprocket is for a 520 chain. Do we use 520 for both chains, switch to 420 from the jackshaft to the axle or 420 for all? I dont know if I can find a 420 sprocket to fit the output shaft on the transmission.

This cart will be driven primarily off-road so I'm thinking a solid rear axle and a front suspension to absorb irregularities.

I am planning on welding up a frame from 1" square tubing (.06 wall), or maybe 1.25". Are there any ratios or general guidelines for proportions? The drawing I'm working on now has the frame at 36" w x 36" tall (roll bar) x 96" long. 8' seems really long.

Drivers will be 12, 10 and 40.

I hope someone here finds this project interesting and has some solutions for us.

 

[crazykart]

Is the entire rear end of the quad saveable?

If so that can eliminate a pot of your headaches.

Also what was the quad, make, model, etc?

 

[silveravnt]

Is the entire rear

Yes it's a little rusty but in decent shape. It's about a 90 Suzuki 160cc quad runner. The thing about using the whole swing arm and rear axle is that it would put the seating position so far ahead of the rear axle.

I'm open to suggestions though

---------- Post added at 08:14 PM ---------- Previous post was at 08:08 PM ----------

Oh yes. Another problem with the rear end is it only have a 29 inch track

 

[OzFab]

This really could have continued on from your previous thread but, I'll let it go as this is more of a build thread, the previous thread was a query...

Based on your questions, I wouldn't consider you a noob, you seem to have done your homework & know what you're doing, both good signs

Searching the internet, it seems not many people have built a two seat kart with a quad motor. They are usually 1 seat beside the motor since the output sprocket of the motor is at the left rear and the chain pretty much needs to go rearward.

We've seen quite a few builds like yours &, yes, they did exactly what you describe next...

Our idea is to use a rear mounted jackshaft so we can mount the motor more over the rear axle and so we can gear it down. The transmission has 5 speeds and I think at least at first I want to limit the top speed.

Until the kids get used to it, simply instruct them to only go to third gear (or whatever); when they can handle one gear, they can kick it up to the next gear...

Another hurdle with our engine is that the output sprocket is for a 520 chain. Do we use 520 for both chains, switch to 420 from the jackshaft to the axle or 420 for all? I dont know if I can find a 420 sprocket to fit the output shaft on the transmission.

Having two different pitched sprockets on the jackshaft will make absolutely no difference...

I am planning on welding up a frame from 1" square tubing (.06 wall), or maybe 1.25". Are there any ratios or general guidelines for proportions?

The "rule of thumb" is larger tube is more desirable than thicker tube; if you don't think 1" thin wall tube will be strong enough, step up to 1.5"; 1.5" thin wall tube is lighter & stronger than 1" thick wall tube...

The drawing I'm working on now has the frame at 36" w x 36" tall (roll bar) x 96" long. 8' seems really long.

The frame dimensions don't matter as much as the wheelbase:track ratio, which ideally should be close to 4:3 so, with a 36" track, wheelbase should be around 48"; with an 8' frame, that means 2' of overhang front & back...

 

[crazykart]

What he said ^^ lol.

My idea was to use the original swing arm, albeit widened. With that the engine should be a good distance to add a jackshaft for regearing, will give a good pivot base, and already has a sufficient mount set up.

You could make the swing point at the base of the seat, maybe adding a bar just behind the seat for a shock mount as well.

What I would say is to draw up, just a quick sketch, of hiw you were thinking of designing it, and we can all throw out ideas from there. Like this: is the front end a-arms still intact? If so you could cut that front end in half, and use that for your suspension...