Clutch noise

Bubby

Member
After we ran a practice lap or two Saturday, we developed a wicked rattle/popping noise that sounds similar to a chain binding. Took the clutch off and everything seemed fine, chain and guard are clearing fine. Put the clutch back on and it still did it. starts as soon as he gives it a little fuel, then seems to stop when it gets up close to speed. With the kart on the stand and feathering the brake a little, you can clearly see the bail (? inside case with the discs and driver) stops turning intermittently. I'm thinking that when the clutch engages, it should all turn obviously, right?
 

flattop1

Dawg 89
Yes . Your descripton initially says brass bushing in the driver . Is that the case ?
The other scenario is the clutch key is sheared ?
It is a disc clutch obviously needs a thorough inspection . Bad discs , stone caught in there thrust bearing gave up .
 

GClary

Member
You are using a key correct ? How old is the clutch ? Could be that it needs rebuilt . As you stated , that on the stand , with slight brake feathering , that it does the same thing . How much throttle are you giving it ? What is the clutch set at for lockup ? Check and make sure that the clutch isn't coming in contact with the seat when the arms expand . Sounds like it may need a good cleaning and inspection . Make sure the air gaps are within spec .
 

CarlsonMotorsports

Premium User
If the key was sheared the kart wouldn't get up any speed. Sounds like chatter, are the settings normal, is a spring broke, are the disks worn out.

We ran a race once where the clutch retaining bolt fell out on the grid and the key slid out. Someone (ie me) left the bolt loose when changing the clutch between races - don't know how that could have ever happened...DOH) The kart barely left the grid, but once on the track, the kart gained speed and worked fine at speed. (This was an oval track, fwiw.)

I was thinking the OP's key could have sheared similarly to a flywheel key shearing, where it catches sometimes, and slips others.

OP, if you do not see something obvious, endplay in the clutch, worn, or missing parts, etc, send that clutch off and have inspected/gone through. Having a fresh clutch that you can count on really eases the mind.
I'd be glad to take a look at it for you. Our shop is not busy and we're still working through this coronavirus.
You are welcome to call the shop, or send your clutch in.


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🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
31 years of service to the karting industry
215 N. High St.
Linden, IN 47955
765-339-4407
bcarlson@CarlsonMotorsports.com
 

Bubby

Member
Thanks for all the advice. Clutch was new last year, and sent back for refresh a few months ago. Key not sheared, nothing touching anything. I put an old Bully on that I had and it doesn't do it. I am sending it back today for them to check it out.
 

sundog

Member
We ran a race once where the clutch retaining bolt fell out on the grid and the key slid out. Someone (ie me) left the bolt loose when changing the clutch between races - don't know how that could have ever happened...DOH) The kart barely left the grid, but once on the track, the kart gained speed and worked fine at speed.
I'll bet you've got some great fish stories.
 
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