TK125GK-7 clutch keeps burning up Need help

[Barefooter]

I am new to go karts and purchased a brand new 2 seater go kart( with 300lb weight limit) what I thought was a nice one for my 7 and 6 yr old boys. Unfortunately I have learned the hard way about internal clutches with this particular set up. I have a Polaris Turbo S that I rock crawl with and while I know my boys cannot follow me I want to be able to take them out on easy trails. They are bored riding with me and I don't blame them. I drove the kart on the pavement( I weight 240lbs) and could tell right after I bought it something was wrong with the clutch. We took it out with the boys and within 15 mins of a gravel parking lot it burned up the clutch. I paid for it to be replaced and changed the oil in the motor. My oldest weights roughly 55lbs and has burned the clutch up while riding in a relatively flat field within 45 mins of driving. He is very coachable and kept his momentum while climbing what tiny slopes where in the field. Returning the go kart is not an option as I have tried to make that work. I don't feel right about selling it to someone else either for them to have the same problem. I figured I have a few options and was looking for advice or a direction to go to so I can research which option would be best for me. I am not sure how much information you would need to help me but I will give what I know.

13 tooth sprocket on engine
38 tooth sprocket on axle
18x9 tires

Options:
1. Change sprockets to lower gear ratio( I was told it would be difficult to source correct sprockets with Chinese build).
2.Install CVT on current engine( Not sure if this is possible but this would be my preferred option)
3.Replace engine with 150cc engine with CVT( New swing arm needed ?) What is a 125cc engine worth with less than 2 hrs on it?
4. External gear box

 

[madprofessor]

A larger axle sprocket should be in your future first. It's a 6-bolt onto a sprocket hub, shouldn't be terribly hard to get a match with the known bolt circle measurement and chain #size.
A CVT would require a complete redesign of the drivetrain to make it fit and work, still wouldn't address that internal clutch.
Enlarging the axle sprocket would be basically an unnoticeable change, fairly inexpensive, and might do enough by itself.
Is there a clutch adjustment on that thing? Sure it's fully engaging as adjusted?
Really nice karts there, by the way.

 

[Barefooter]

A larger axle sprocket should be in your future first. It's a 6-bolt onto a sprocket hub, shouldn't be terribly hard to get a match with the known bolt circle measurement and chain #size.
A CVT would require a complete redesign of the drivetrain to make it fit and work, still wouldn't address that internal clutch.
Enlarging the axle sprocket would be basically an unnoticeable change, fairly inexpensive, and might do enough by itself.
Is there a clutch adjustment on that thing? Sure it's fully engaging as adjusted?
Really nice karts there, by the way.

I was told by the shop that replaced the original clutch that there was no adjustment. I thought if I used a different weight oil it might help or possibly a better oil but I haven't found any information on that yet. I'm still looking through posts here.
How would I be able to tell what size chain I had on here? If it gave me better options I wouldn't mind changing the chain and both sprockets.

 

[Denny]

I have no idea what kind of engine is on that thing but I can tell you this. That gear ratio ain’t gonna cut it. It seems way to high. What is the top speed on that thing now? Are they pedal to the floor kind of kids, or do they take it kind of slow? If they go slow the clutch might not be fully engaging and slipping. A centrifugal clutch can destroy itself after only a few minutes driving. As far as finding driven sprockets that should be way easy. The drive sprocket might be a little harder, but doable. May the force be with you!

 

[Barefooter]

I have no idea what kind of engine is on that thing but I can tell you this. That gear ratio ain’t gonna cut it. It seems way to high. What is the top speed on that thing now? Are they pedal to the floor kind of kids, or do they take it kind of slow? If they go slow the clutch might not be fully engaging and slipping. A centrifugal clutch can destroy itself after only a few minutes driving. As far as finding driven sprockets that should be way easy. The drive sprocket might be a little harder, but doable. May the force be with you!

I want to say somewhere around 30-35mph. My youngest can't reach the pedals but my oldest stayed in the throttle pretty good.

 

[Denny]

I figured with that ratio it would do about 70 mph! Because of that engine your in a tough spot. It is probably internally geared down 2:1 in addition to the external gearing on the sprockets with about another 2:1 with the sprockets. Not good!
You need a ratio of 6:1 with that size rear tire. Go to Gokart Supply site and read and do some research looking at all the parts. Pay close attention to the cvt section.
This is going to sound painful but with the type riding you want to do you would be better off converting to a 212 and cvt. Can you weld and measure? It can be done in a solid weekend if you can.
SORRY!

 

[madprofessor]

About chain size question................Go to "gopowersports.com", click on "gokart parts" on the top banner, click on "chains and sprockets" on the dropdown menu. There's a good chart that explains what you need to know.
From there you can browse around to see what's available in drivetrain components suitable for your kart.

 

[Wvguy]

Hey guys I just got one of these things, yall got any websites for finding parts for these things or other machines that most parts cross reference with? I need a rear axle bearing setup and for the life of me I can't find nothing for this machine. Thanks