Kart Rolls When Idling

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olddognewtricks

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Can anyone offer suggestions on how to stop my go kart from creeping forward while in idle?

I have a brand new kit that I built. Everything ended up working fine after the build and some tweaking.

For some reason, I got carried away and decided to "upgrade" my clutch. The new clutch has the same number of teeth as the original kit clutch, and is designed for the same size chain I am using.

Immediately after installing the new clutch, my go kart now inches forward on its own when it's in idle.

Aside from the new clutch, nothing else has been changed.

In delicately and carefully trying to fix this "creeping" problem, I have tried the following:

1) I slowly turned the engine's idle screw and watched for results after each 1/4 turn. Eventually, I reached the point where the idle low speed caused the engine to stall. Even by increasing the idle screw just enough to keep the engine running, the kart still creeps forward.

2) I disconnected the throttle cable and made sure that the engine's throttle arm is closed.

3) I am on a perfectly level surface of a concrete garage floor.

4) The chain tension seems perfect...a small amount of "play", not super tight, not super loose.

Before installing the new clutch, I did not have this problem. My engine is a Predator 212.

Can anyone offer suggestions on how to stop my go kart from creeping forward while in idle?

THANK YOU!!

---------- Post added at 05:42 PM ---------- Previous post was at 05:27 PM ----------

My best guess is that the chain might be just a tad too tight. Since everything is effectively new, and since the clutch is new, it's unlikely something has gone bad already.

And, since the kart's forward movement when idling is VERY slow (but steady), all I can think of is chain tension.

I'll start with the simplest possible solution, and move the engine a fraction in order to loosen the chain. I'll re-post if that resolves it.

In the meantime, I still appreciate suggestions!
 
JTSpeedDemon

JTSpeedDemon

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Try oiling the clutch bushing, that frequently causes symptoms similar to what you are describing.

What kinds of "upgrades"? Did you upgrade it yourself or buy it upgraded? If so, got a link?
 
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mckutzy

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I hear ya, I also run my clutch inboard, it is a bit of a pain to get to...

Just on the washer/snap ring.. itll suck in to the bushing... Helps to move the drum a few times around be for starting the motor...
 
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olddognewtricks

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Unfortunately, oiling the bushing did not help. In further examination, I think the chain tension is perfect. So, I don't really know what to try next.
 
Brianator

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What kind of kart are you working on? If its really light that could explain a bit as it's a heavy duty clutch, heavier carts probably wouldn't be affected and racers don't care about idle speed. Maybe the shoes need to wear in? A bad spring inside perhaps?
 
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olddognewtricks

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Yes, nut is loosened. Throttle arm moves freely and snaps back to idle. However, I wonder if maybe not going 100% back to its neutral idle position. Maybe, there's just a tiny bit of room left over in the "open" throttle arm that is causing the clutch to engage. I'll have to dig around under there to see the springs. Maybe I can figure something out or add another spring to be sure the throttle arm is being pulled fully back to idle.
 
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olddognewtricks

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Brianator said:
What kind of kart are you working on? If its really light that could explain a bit as it's a heavy duty clutch, heavier carts probably wouldn't be affected and racers don't care about idle speed. Maybe the shoes need to wear in? A bad spring inside perhaps?
Click to expand...

Brianator - that is a great observation and might very well explain it. It is a single seat go kart like the attached photo.

Soon, I'll be adding bigger 15" tires on the rear to replace 13". Maybe that will help offset some of the "pull" from the new heavy duty clutch. I assumed "heavy duty" clutch simply meant built with tougher parts, but maybe it also tends to engage easier under a lighter load as you implied.

Good thoughts. Since it doesn't roll away too fast right now, I'll just leave it alone until I see how it reacts with the bigger tires/wheels. No sense it fixing a problem that might not really exist.
 

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Brianator

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Good plan! Lol. That indicates that either the clutch needs a break in period, something is up internally (manufacture defect) or mabey it was dropped at some point and the outer bell isn't perfectly concentric? Is it pretty easy to hold it back? Sure looks like a nice (and light) kart!
 
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olddognewtricks

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Here's how it turned out.

First, a little history. I bought this "heavy duty" clutch from Go Power Sports. Upon trying to install it, it absolutely would not fit on my engine drive shaft.

Before anyone comments..yes, the bore on the clutch and the diameter of my drive shaft are the same, 3/4". No question about it.

Several of the reviews for this clutch had stated there was a fitting problem, but I ignored the warnings. Those other reviews were 100% correct.

It took a lot of dremel sanding and a ton of force to get this clutch on.

After deciding to let the "rolling" problem mentioned above take care of itself after some clutch break-in time, the clutch started smoking yesterday.

So, I spent 2 hours trying to get it off. Finally got it off and put on my older (but functional) clutch. The older clutch does not exhibit the "rolling" problem that started this thread.

Bottom line....I should have stopped the installation of this piece of junk heavy duty clutch when I first noticed that it wouldn't readily slide onto the drive shaft. The fact that it later started smoking is yet another "clue".

I wrote a 1-star product review about this clutch for the product page on Go Power Sports and I recommended they remove this clutch from their website until the bore measurements are corrected by the manufacturer.

It is sad that Go Power Sports will not publish my product review.
 
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jmaack

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I read a review stating the same thing about using emry cloth to get clutch to fit. My guess is tolerance stacking between the clutch and the predator which would have larger tolerance. thus the tight fit.
 
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olddognewtricks

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This wasn't "tight". It doesn't fit. Since I am not able to return it for a refund (I had to cut it apart to remove it), I can tell you that it wouldn't go on even after repeatedly pounding it with a hammering. To get it off, I had to cut it apart like a surgeon cutting open ribs for heart surgery. Luckily, I avoided damage to my drive shaft.

Lesson learned...if something that is designed to specifically fit but doesn't come anywhere close to fitting, immediately return it and try a different product.

I tried to re-engineer it to make it fit and paid the price.
 
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