Go kart sprocket too close to ground

[Denny]

I know, I just decided to show him how frustrating it is when people refuse to listen to honest, solid advice.

 

[Master Hack]

All he needs is a 6.5 inch diameter 72 tooth #35 split sprocket with some never heard of hub pattern. Simple!

 

[bladeZjack]

Thank you guys so much for the 2 index tables. These really helps me choose the replacement sprocket size. So, based on the Gear Ratio for Sprockets Index Table, I currently have a 72 tooth sprocket, if I replace it with a 62 tooth sprocket, my speed would increase right? It says “lowering the ratio increases top end speed”. Thanks.

 

[Whitetrashrocker]

Sprocket size is totally dependent on your gear ratio not ground clearance. You dont choose what diameter. You live with the ratio you need.

Yes lowering the ratio increases top speed but you loose the low end torque needed to get you moving.

Ever ride a 10speed bike?
Same concept. In low gear or high ratio you pedal like crazy but dont go very fast. You can even do easy wheelies, because you have the torque.
Now switch to high gear or a low ratio and you can't even get started, its hard to pedal, but once you get going, you can go really fast.

You technically could gear to go 100mph, but you would never be able to take off. You would have to be pushed to a point where the engine can work that ratio.

On the other side you could gear where you only go 10mph, but you would have the torque to climb a mountain.

With karts we try to stick to around 6:1 gear ratio. Its not exact but its works for many.

If you need ground clearance and using a smaller axle sprocket than you will need to use a larger drive sprocket to bring your ratio back to a usable range.

A taller tire will give you ground clearance but it will also change the overall ratio and sprocket change is how you correct it.

 

[Grizzlymi]

Perfectly explained.

 

[Master Hack]

Perfectly explained.

It didnt say a word about 6.5 sprockets....

 

[bladeZjack]

Hello everyone! The sprocket arrived today. I’m gonna need advice on how to install it properly. I remember the original sprocket had some sort of misalignment or uneveness. When I turn the wheel, there is a point where the chain gets very tight, but I keep turning, there is also a point where the chain is very loose. How do I keep this from happening? Is there a technique or tool I can use to make sure the sprockets 2 halves are evenly installed? Thanks!

 

[Whitetrashrocker]

What your describing is either a worn-out chain or you have a bent axle.
To check the axle spin it and watch the edge of the sprocket hub. It should spin concentric and not wobble.
You can take a stick and brace it against the frame and use it as a pointer. Get it close to the hub and spin the axle. The proximity of your pointer makes it easier to tell.

When I put on a new split sprockets I use the chain wrapped around to align the teeth with the chain. Then tighten the bolts.

 

[bladeZjack]

Thanks for the reply. It looks like there’s a slight bend on the axle. I placed a ruler with the tip barely touching the axle and when I turn the wheel, the distance between the tip of the ruler and the axle fluctuates just a tiny bit.
I will be shortening the chain since I’m using a smaller diameter sprocket. I just ordered a chain breaker tool. I’ll be posting the updates here.
Thanks!

 

[Whitetrashrocker]

Check your old chain.
If theres any tight links that dont bend well its wore out.
You can also lay it flat on the ground and see how much lateral bend it has. Should be little to none.
If it bends 90° like the left one its wore out.

 

[bladeZjack]

Thanks for the advice. I’ll check.

 

[bladeZjack]

Hi guys, I lost the photo of how these wires get connected to the kill switch. Wires 1 and 3 are from the kill switch. 2 and 4 goes to the motor. What’s the “On” mode for the motor? Is it when it’s in a closed loop connected to the ground or is it when it’s in an open loop disconnected from the ground? Thanks!

 

[Whitetrashrocker]

Open circuit.
Ground the wire to kill the coil spark.



Attach yellow as shown. Bullet connectors work one way.
The blue circled ring terminals go under a bolt head for ground.

 

[bladeZjack]

Thank you for the instructions. I’ll post updates.

 

[bladeZjack]

Hi guys, got the chain shortened and wiring all connected. Motor is running and kill switch functional. Got a quick question on checking the oil level. I’ve checked a couple of YouTube videos on Predator 212 oil levels. All the videos just mentioned the front dipstick. With my engine, when I unscrew the front dipstick, oil would leak out. So I think the oil level is okay. But the back dipstick is very dry. When I unscrew it to check the oil level, the tip of the dipstick doesn’t even have any oil on it. Should I add oil so the back dipstick would have oil at least to mid level? Thanks.

 

[ezcome-ezgo]

Jack up the kart so the engine bottom plate is as close to level as possible, then check the oil level. Should be visible in both ports.

 

[Hellion]

Jack up the kart so the engine bottom plate is as close to level as possible, then check the oil level. Should be visible in both ports.

Seconded. This is an acceptable way to both check the oil and add new oil. In some of your photos the angle of your motor mount can't really be seen, I almost missed it.

For some racing engines, the amount of oil used in the crankcase is by volume and not determined by the mark on the dipstick. So they put in sometimes 12, 14 or 16 ounces for example, instead of the factory 20-22 ounces, and these smaller amounts are used with the angled motor mounts. I see 7° and 15° mounts mentioned most often. But that's a rabbit hole or a can of worms topic.

So essentially the racers use "just enough" oil.

 

[bladeZjack]

Thank you. Will do. I just noticed the engine mount is inclined. No wonder one port shows no oil hehe. Thanks!

 

[Hellion]

I just noticed the engine mount is inclined. No wonder one port shows no oil hehe. Thanks!

You’ve got to be joking.

 

[bladeZjack]

No I’m not. I’m new to all this. LOL!