Clutch problem

[Kettenbrecher]

Hello

I recently just finished my first ever kart build, and after only a few test-runs, I have encountered a problem almost certainly with the clutch. When I start the engine (Predator 6.5hp), this ghastly grinding/screeching noise emanates from the clutch. Accompanied by this is the kart rolling forward, so I suspect the clutch is engaging prematurely. This did not happen the first few times; it was working perfectly. Am I correct in my assumption? Is a new clutch the only way to right this?

 

[mckutzy]

Hello and welcome
What is your gearing ratio(the tooth count on both the clutch and rear sprocket).
Post some pics of you ride.

 

[chancer]

Could just be your idle is too high, causing the clutch to engage, Except the terrible sounds. What kind of clutch, and what he said plus your rear tire size would help.

 

[landuse]

Your chain could also be too tight. There should be about 1/2" of play when you pinch the top and botton of the chain together

 

[Kettenbrecher]

Hello and welcome
What is your gearing ratio(the tooth count on both the clutch and rear sprocket).
Post some pics of you ride.

Thanks for responding. The clutch has 12 teeth and the sprocket has 72. I can't get pictures right now, and the thing is an ugly SOB anyway.

Could just be your idle is too high, causing the clutch to engage, Except the terrible sounds. What kind of clutch, and what he said plus your rear tire size would help.

I don't think the idle is the problem, for it was working just a day ago. The clutch is centrifugal, and the rear tire size is 11". Hope that helps

 

[tazmannusa]

I have a couple small karts with the cheaper clutches and what happens is the bushing gets dry and causes that , just dump a little oil next to sprocket so it lubes the bushing , don't get to carried away with the oil, you don't want it in the clutch drum or weights

 

[itsid]

well a clutch needs maintenance, a few drops of oil on the brass bushing every now and then;
apart from that and since your gear ratio as well as tyre size seems to be just right
(that is if your kart with you in it doesn't weigh half a metric ton)

the only thing that is indeed left is chain tension and idle speed.

Yes, the idle speed is NOT set and forget I'm afraid,
it can shift ever so slightly with humidity, air temperature etc.
maybe just enough to engage the clutch..

so while you're checking the chain tension as Paul (landuse) suggested,
check your idle speed again, turn it down just a tiny bit and see if the engine still runs smoothly without engaging the clutch.

if not, remove the chain, maybe even the clutch and do a full maintenance (to be safe)
good cleaning and a few drops of oil on the bushing should do in most cases.
because of the noise... I recommend that anyways, keep the bushing alive or you might need to replace it sooner than you'd want

'sid