Go kart clutch smoking

[Revlimiter]

I have a go kart with a 7hp HF predator and i installed a 12 tooth max torque clutch with a 60 tooth sprocket on 1 wheel drive and the clutch starts to smoke a lot after just 1 minute of riding. it also started to make this ching/cling noise after i was heading to my garage. didn't ride it a lot just first time after rebuild and yes its a one wheel drive cart. i bought the frame off of Craigslist for about 60 bucks, it just needed one spot to be welded since who ever welded it wasn't good at welding. also it came with a 13 tooth it think it was comet clutch and a 72 tooth sprocket except no chain. they said the motor blew. I think they were using a clone 6.5hp engine also because the mounting holes on the plate are the same to the HF predator holes. the chain I'm using for my setup is a 35 link the previous go kart frame owner used a 40/41 chain for their 72 sprocket and 13 tooth clutch setup. I don't know what to do, i think i go up higher in gear or get a jack shaft, except there is no room for a jack shaft. My friend is selling a couple of sprockets from his old go kart projects for really cheap prices so i might buy a higher gear axle sprocket and keep the 12 tooth clutch. any help would be helpful. Will a 72 tooth axle sprocket work?

 

[Doc Sprocket]

Sounds to me like you're geared to high. With a 12T clutch and a 60T axle, you're geared at 5:1. Try swapping out that axle sprocket for a 72T. That will bring you down to 6:1.

it also started to make this ching/cling noise?

Chinese parts...

 

[Revlimiter]

Thanks for the help.

 

[Doc Sprocket]

You're welcome. May I suggest a seat? That's a heck of a place to get a splinter!

 

[Revlimiter]

Yeah im trying to find a cheap place to get a seat for right now im looking into this http://cleveland.craigslist.org/grd/3526684457.html
but im going to have to ask my friend to weld it on for me since i dont own a welder.

 

[jamyers]

Yep, I'm thinking it's geared too high. 6:1 is about as high as most karts can go, you're above that.

The ching ching noise could be anything; bad bearing, loose chain, misaligned chain / sprockets, etc. You might put it up on stands, run it, and see if you can spot where the noise is coming from.

 

[jerseykid]

sounds to me like the chain may be to tight i would check your chain tension and alignment

 

[Revlimiter]

the chain isnt tight at all, it has about 4/5 of an inch slack, it perfect, the noise is comming from the clutch and it also turned into a different color like it lost its paint, its now redish black

 

[Revlimiter]

You can see that there is no room for a jack shaft. also im about 200 lbs and i need this thing to climb up about 20-35 degree hills, so a 72T would be great? also if i get a 72T the chain wont be like 1mm away from the tire

 

[jamyers]

A 72-tooth axle sprocket with the 12-tooth clutch sprocket would give you 72:12 = 1:6 gearing, which with roughly 14" tall tires ought to work well.

Yup, that clutch has been hot!

 

[landuse]

If it were me, I would get a 10T clutch, and a 72T sprocket. That would give you a 7.2:1 gear ratio, and with your weight and the fact that you want to go up 35 degree hills (dang that is steep, and will probably never make that), you are going to need all the help you can get.

The noise from your clutch could also be your bushing that needs a bit of lubrication.

To sum up - personally I don't think a 72T with your existing clutch tooth count is going to cut it. My suggestion would be a 72T as well as getting a 10T clutch for a 7.2:1 gear ratio

 

[Revlimiter]

So thats why the previous owners engine probably seized up, they were running a 72T axle and 13T clutch which is around 5.5:1 gear ratio which is way to high. But wouldn't i have to buy a brand new 10t clutch with a 40/41 chain and a 40/41 sprocket because i am running it with a 35 chain and i cannot find a 35 pitch 10t clutch. I also just went into my garage to check what the tire size is its 14 inch tires, what jamyers said that 14 inch tires would go good with a 12T clutch and a 72T sprocket. also my drive way is on a hill that is about less than 15 degrees but i also have hills going into the backyard which i will be mostly riding because its flat back there and has a good amount of trees to swerve past. the hill leading to the backyard is about also less than 15 degrees.

 

[Doc Sprocket]

Without a jackshaft, keep in mind 2 factors. 1) Smaller tires are your friends, when it comes to maximizing gear reduction. 2) Bigger axle sprockets are equally friendly. To get the most out of your setup for what you want to accomplish, put on the smallest tires you can reasonably get away with- 11" is pretty common for little fun karts. Then- install the largest axle sprocket that will fit without hitting anything, including the ground. To heck with the math- this is as good as it gets without a jackshaft or CVT.

And- a 35* hill isn't gonna happen. You'll either run out of gearing, or run out of traction.

 

[jamyers]

Good catch, toystory - I missed the hill climbing bit.

Let me amend my previous gearing remarks: On flat pavement or dirt roads, 6:1 will work with those tires, BUT even lower gearing would be better, especially is you're going off road or up hills. Check out the gearing, tires, speed sticky.

 

[Revlimiter]

I could go down to 11 inch tires or even 10 inch tires because harbor freight sells them pretty cheap. i just need tires that run on bearings because of the one wheel drive setup i use. but first ill try out the 72T sprocket with 12T clutch and see if it will work for me, if not i will do the 11 inch tires with 72t sprocket and 12t clutch

 

[landuse]

I could go down to 11 inch tires or even 10 inch tires because harbor freight sells them pretty cheap. i just need tires that run on bearings because of the one wheel drive setup i use. but first ill try out the 72T sprocket with 12T clutch and see if it will work for me, if not i will do the 11 inch tires with 72t sprocket and 12t clutch

Do NOT use the HF tyres. They are rubbish and will be wrecked in 30 minutes. I would try the 12T/72T combination and see what happens. Just keep in mind if you do use the 11" tyres the 72T sprocket might be scraping along the ground

 

[buckwheat]

Your clutch is sitting way out on the engine's shaft. That is really putting a big over hung load on the engine's crankshaft and bearings.
Is there a way you can relocate the engine to reduce that clutch's over hang?
Perhaps, when you have your friend do the welding you guys could cut off the engine's mounting plate & move it over to reduce the distance the clutch is sitting from the engine.

 

[Revlimiter]

the clutch is hanging out 1inch off the shaft. ill try to relocate the engine because there is already a bunch of pre drilled holes in the mounting plate that i can move the engine around then push the clutch in a bit more.

 

[Revlimiter]

so i repositioned the clutch but im worried that the clutch is to close to the motor.

 

[landuse]

Looks good to me