Help! My Go Kart Clutch is Smoking!
Kind of alarming really. One minute your having fun and the next your almost on fire!
**Be very careful. If the clutch is smoking it is crazy hot! Let the engine and the clutch cool down before doing any work.
A go kart clutch that starts smoking is a fairly common issue and can be caused by a couple different scenarios.
The Cost of a centrifugal clutch these days is not worth your time to disassemble, replace parts and then reassemble.
At Better Karting we are here to help you maximize your go karting fun. We want to make these fixes simple and fast so you can get back out there and have fun!
My Go Kart Clutch is Smoking
- The clutch might be slipping
- The clutch might be overloaded
- The clutch might be worn out
- Incorrect Gear Ratio
Any of these four situations can cause a clutch to smoke. Once a go kart clutch starts smoking you have very little time to stop the damage.
**Be very careful. If the clutch is smoking it is crazy hot! Let the engine and the clutch cool down before doing any work.
1. The Clutch Might be Slipping
What does this mean?
That the go kart clutch has fallen and cannot get up?!
No, it simply means that the shoe to drum engagement is not locked together. Causing a high amount of friction (heat). The clutch gets so hot that the shoe material and lubricating oils start to burn off and the smoke appears.
What happens when a Clutch is Slipping
At an idle the shoes are kept in and away from the drum by the clutch springs.
As the engine speed increases, the shoes (weights) want to expand away from the center of the clutch. They expand until they make contact with the drum. Once contact is made with the drum friction causes the shoes to lock together with the drum.
This in turn will drive the rear axle and off you go!
Friction builds heat.
If the shoes are locked with the drum there is no friction.
If the shoes are making contact with the drum but not locked as one you will start to create a large amount of friction or heat.
The smoke you see are the clutch shoes melting away, lubricating oils or grease and the metal housing literally starting to melt.
You can clearly see what damage can be done so fast when you go kart clutch is starting to slip.
This particular clutch was still in service but has seen better days for sure!
2. Clutch is Overloaded – Why is my Go Kart Clutch smoking?
A go kart clutch can only create so much force between the shoes and the drum.
In a racing application you can have a clutch with 2, 3 or even 4 discs in them! With a high horsepower engine you will need a heavy-duty clutch that can handle the torque and not slip.
Something is going to have to give.
Whether that be the clutch or the engine.
The engine only has so much power and the clutch can only hold on for so long until it starts to slip.
An overload could be anything from too much weight on the go kart, incorrect gear ratio, going up a hill, stuck in the rut or ditch or even the brakes are applied.
All of these are examples of overloading a go kart.
If the engine has enough ass to power through the clutch then get ready because that puppy is going to be smoked!
Always be aware that if your go kart is stopped but your engine is increasing in RPM you might be damaging your clutch.
3. The Clutch Might be Worn Out
Maybe its time… time to buy a new one.
A clutch is a wear item. It takes a lot of abuse. Constantly engaging and disengaging. The parts are always moving. The parts are subject to extreme temperatures as well. Extreme temperatures will break down moving components even faster.
It is a wonder that go kart clutches last as long as they do!
You could just have a clutch that the shoes are toast on. They have lost their friction properties that make them do what they do.
Once a go kart clutch starts to smoke and slip the damage is done. It cannot be reversed.
If we take a look at this clutch you can see the shoe material on the inner body. This shoe material can wear off and then you have steel to steel which is not good.
Steel on steel does not create enough friction.
4. Incorrect Gear Ratio
The incorrect gear ratio will create excessive load on the engine. The engine will not have enough power to turn the axle.
This is how it will go down…
You start the go kart and everything will be fine.
You hop in and hammer down
The engine RPM will increase and then start to drag down and lower again.
You don’t pay much attention so you assume you need more throttle. (When in doubt throttle out!)
Soon the engine RPM will greatly increase to as fast as the engine can run… but your still in the same spot.
Finally, you get out and take a look at what the problem might be. You find the clutch is red hot and smoking!
Why did this happen?
If you have an incorrect gear ratio on a go kart it can create way too much of a load for the little engine to power through.
Determining the Best Gear Ratio for you
This all depends on what you are doing.
If you are building a go kart start with a 5:1 or 6:1 gear ratio. You may have to deviate from that a little but that should get your close. And you won’t blow up your clutch!
When we were racing, we would constantly be changing gear ratio. Especially on tracks we haven’t been before.
Once you find the best gear ratio for your go kart and engine you usually do not deviate too much from that.
If we raced on a really big track, we would have a lower gear ratio for higher speeds. (Closer to a 1:1 will increase top end speed)
If we race on a smaller track with sharper turns, we had a higher gear ratio. This would help with pulling up out of those tight corners.
My Manco Go Kart Gear Ratio
My little Manco go kart has a 212 Predator Engine installed. Very small wheels, maybe 8″ in diameter.
The clutch has a 12-tooth drive gear, and the drive wheel has a 60-tooth driven gear.
Gear Ratio = Driven/Drive
60 \ 12 = 5
My gear ratio is 5:1.
If I was to increase the drive gear or decrease the driven gear my gear ratio would be lower, and my top speed would increase
Yup, you guessed it.
If I decrease my drive gear or increase my driven gear my gear ratio would increase, and my acceleration would be better.
Let me know How you Smoked your Go Kart Clutch!
I am here to help anyone, and everyone be a Better Karter!
Let me know how you smoked your go kart clutch. I would be more than happy to assist in any way I can to help you figure out the best fix!
If you need help with any other go karting problems, be sure to return home to learn more!
