Cluch getting too hot?

[chetcpo]

How hot are the clutches on the horizontal shaft 6.5hp (Tucumseh) engines supposed to get? I bought a used kart and the clutch on that thing got so hot it started smoking and changing colors. I put on a new cluch I purchased through Northern Hardware and it smokes and gets rediculously hot as well after just a few minutes of running.

Is this normal?

 

[Kaptain Krunch]

No, not normal.

Count the number of teeth on the clutch sprocket, and the number of teeth on the axle sprocket and post them here, also post tire diameter.

Some people claim there clutches never get too hot to touch, however its all in the gearing, When i still had my 5.5hp tecumseh on my kart, the clutch would get fairly hot but never smoked nor changed colors.

 

[r_chez_08]

mine did this, so i upgraded to a torque converter. usually it is a result from a bad or worn clutch, or a high ratio.

 

[Russ2251]

Not that I am the best example, but my clutches never got so hot that I could not hold them. Very warm at best.
Did not vary from kart to kart, live axle or 1 wheel drive...one engine or two.

 

[chetcpo]

Here's a pic of the setup It's a factory build kart. You see anything jump out at you *** unorthodox?

 

[Russ2251]

Count the number of teeth on the clutch sprocket, and the number of teeth on the axle sprocket and post them here, also post tire diameter.

We need these numbers!!!

 

[Kaptain Krunch]

Here's a pic of the setup It's a factory build kart. You see anything jump out at you *** unorthodox?

I cant help at all till i know the sprocket tooth count on clutch and on axle/tire and the tire diameter.

It may be a factory built kart, but something as simple as someone changing the rear tires could cause your problems.

Also, jack the rear end up and make sure all your tires spin freely, without any major slop in the bearings/bushings.

 

[Doc Sprocket]

Also, jack the rear end up and make sure all your tires spin freely, without any major slop in the bearings/bushings.

While you're at it, check front wheels spin nicely, and make sure you brakes aren't binding/dragging. A "Hypercolour Clutch" is not good at all! Does it feel like you're coasting freely when you get off the throttle, or does it decelerate rapidly?

 

[bajagokart]

what sounds like is happening to me is that you dont have enough motor to drive you kart! you engine and clutch is having to work too hard and you clutch is slipping because your engine isnt big enough! my 6.5 hp clone on my go kart did the same thing. i would go about 20 km/h for 5 mins and it would be smoking simply because i didnt have the power needed to drive my go kart and my engine and clutch had to work too hard

 

[porsche930dude]

how heavy are you ?

 

[Kaptain Krunch]

what sounds like is happening to me is that you dont have enough motor to drive you kart! you engine and clutch is having to work too hard and you clutch is slipping because your engine isnt big enough! my 6.5 hp clone on my go kart did the same thing. i would go about 20 km/h for 5 mins and it would be smoking simply because i didnt have the power needed to drive my go kart and my engine and clutch had to work too hard

Your engine was not able to push your kart, so it bogged and allowed the clutch to partially disengage and slip. Causing the heat.

 

[chetcpo]

We need these numbers!!!

Sorry I had to get a free minute to get the chain off. It's 10/60.

 

[Doc Sprocket]

Normally, I think that's considered acceptable (6:1). Are your wheels tall? Are you ahh, gravitationally enhanced?
EDIT- second look at pic indicates tires aren't too large

 

[bajagokart]

judging by how big the sprocket is im guess there 13 inch tires

 

[Kenny_McCormic]

What kind of terrain are you driving on?

 

[chetcpo]

Driving on flat ground, (because it won't go on uneven ground, see my post in the introduction area for more on that) does it whether paved or grass covered. My weight is 175lbs of pure chiseled muscle. I actually bought the kart for my 1st grader and kindergartener sons with the idea being I can ride around with them and teach them to drive it. They weigh about 40lbs give or take each. At some point after I get it to steer properly I'd like for them to be able to drive it by themselves.

 

[Doc Sprocket]

Lots of uphill stuff? Stops and starts? mid-throttle driving? All of these can pan-fry a clutch...

 

[chetcpo]

Lots of uphill stuff? Stops and starts? mid-throttle driving? All of these can pan-fry a clutch...

Not really... I can see how that may cause it to slip and heat up. It seems to me to get pretty darn hot just sitting and idling. This coming weekend I'll fire it up (if it will start) and hit it with my digital IR temp guage after it sits idling for a few minutes and provide a number.


I'm open to suggestions on how to reduce gearing since this thing goes way too fast for my kids when running wide open. Which should help reduce clutch load if I'm not mistaken. I'm not sure it's possible though, given that as it sits the rear cog is almost as big as the tire.

Thanks everyone for the responses. I'm glad I found this site.

 

[bajagokart]

what you could do if all possible, putting a 72T or 80T sprocket on the axel would make it more torquey and would reduce your speed! I would try that before i tried anything else

 

[Doc Sprocket]

I never thought of the temp gun- I have one too!!! Need numbers to compare it too. Yes, regearing lower will reduce loads and make your clutch's life easier. Given your current setup, I doubt you'll be able to fit a much larger rear sprocket without clearance issues. You will likely have to set up a jackshaft. This is an intermediate shaft on bearings that hold a couple sprockets. Your clutch chain-drives the shaft with one sprocket, in turn the second sprocket drives your axle. Ultimately, you end up with two chain runs, and the ability to gear down much lower than you could without. As an example, My kids' cart is geared at about 16:1 as I recall. To do this without a jackshaft would require a 160 tooth rear sprocket! The wheels wouldn't touch the ground!
EDIT- Just checked- 10T clutch to 32T on jackshaft, then 12T on jackshaft to 60T on rear sprocket for a final ratio of 16:1 reduction. (10/32 x 12/60=16) This keeps the kart slow and controllable while they're learning not to crash into things. Absolute (*&^loads of torque, tho'!
While this is likely a far too low ratio for you, I think it should give you an idea...
Cheers- Chris