Chain is super rough on start but smooths out at higher speed

[Master Hack]

Weight?
5:1 gearing.
our team of experts are checking their Ouija board, crystal ball, and google.
stand by for anin depth solution.

 

[Whitetrashrocker]

What happens if you raise the rear wheels and hand spin the tire. Watch the chain closely. See if it's binding on something or not catching the gear tooth just right.

I watched that video again and I don't see anything obviously wrong.

Edit:
If your chain is stretched, every link is now longer, the sprocket hasn't stretched. So your chain holes and sprocket teeth don't line up anymore.

 

[panchothedog]

How tall are your rear tires? Can't tell much from the few pictures, but they don't look like 10" or 11" race kart slicks. Maybe closer to 15" or 16". If that is the case, then your gear ratio is too high and the clutch is struggling to engage from a dead stop. You are at a 5:1 ratio. If your tires are more than 14" tall you need to be at a 6:1 minimum or even closer to a 7:1 ratio. Or run a torque converter. Your clutch is designed to engage almost instantly. You are forcing it to engage more incrementally which is not what it was designed to do. It ain't happy.

 

[Denny]

It looks like the teeth on the big sprocket are wearing funny too.

 

[Edwin Spangler]

The slightest misalignment will cause that clunk you speak about. I went through hell trying to figure out our "clunk".

 

[ezcome-ezgo]

 

[Hellion]

I am looking for an old Roller Chain thread on the forum, like a FAQ but haven't found one. If one of you gents wants to write one as a FAQ with chain theory, chain “science“ and all the pitfalls plus answers to all the newbie questions pertaining to chain type/size, chain slack, chain tension, and “why does my chain keep falling off?”, that would be splendid.

If there is such an all-encompassing thread here, please point me to it, but I shall keep looking and if I find one, I shall pin it to the top.

 

[Sparkwizard]

Maybe your axle bearings are the problem?

 

[Master Hack]

It looks like the teeth on the big sprocket are wearing funny too

It is NOT funny!

Maybe your axle bearings are the problem

A good point and often over looked! They may turn OK, but do they have excessive runout?
Get the weight off both rear wheels, grad ahold of the tires and see if ya can move dem around.
That means the tires attached to the axle, not the spares in the corner, like Denny once did!

 

[Hellion]

I've checked for stiff links and there doesn't appear to be any

You don't sound 100% positive. It might be worthwhile to verify each link by folding each link back on itself in both directions to ensure there are no binding links. Chains, depending on manufacture and quality control at the factory, can have all kinds of problems. Might be time to get a new chain or try another brand. I've got several different chains for each go kart, some were the originals which were worn but not worn out, etc.

Sprockets too. Get some just for spares.

 

[Master Hack]

There is #35 and #35H. The H designates Heavy Duty. I don't know about 35, but some chains have differences in the regular and H versions. #40 fer example. Ya have 4X, 4X and 4XX they are the same or are they? Only thing in common is 1/2" pitch.
I dont know about 35 as mentioned and l dont wanna look it up. You can, here

RC35H-1R-10FT 35H Roller Chain - Heavy Duty Chain - 3/8'' Pitch - 10ft Box

www.nitrochain.com

 

[Master Hack]

I would suggest replacing both sprockets and the chain, obtained from the same place to insure compatability.

 

[Denny]

It is NOT funny!


A good point and often over looked! They may turn OK, but do they have excessive runout?
Get the weight off both rear wheels, grad ahold of the tires and see if ya can move dem around.
That means the tires attached to the axle, not the spares in the corner, like Denny once did!

You said you wouldn’t tell anyone. You lied!!!

 

[Dinogrant21]

Upadte: I changed to a #40 chain to see if that would help and ineed did not. It was still clunking and I also found that the tension is consitant. For example in one spot it feels solid good tension and then I turn the axel half way and the tension is loose. I tried reajusting everything still nothing im sure something ovious is wrong but I just can't figure it out

 

[Grizzlymi]

Upadte: I changed to a #40 chain to see if that would help and ineed did not. It was still clunking and I also found that the tension is consitant. For example in one spot it feels solid good tension and then I turn the axel half way and the tension is loose. I tried reajusting everything still nothing im sure something ovious is wrong but I just can't figure it out

Sounds like a bent sprocket IMO. That will cause a "bind" in the chain at certain points.

 

[Sparkwizard]

If it is tight on one side, loose with axle 180 degrees away, there is RUNOUT in the system. Most likely sources of runout would be a bent axle, or a sprocket mounted off center. Next probable source would be a bad axle bearing. Have you checked any of those things?

 

[Grizzlymi]

And absolutely a bad wheel bearing could be the issue. They are cheap and easy to replace. You've already got a new clutch and chain, might as well replace the drive sprocket and wheel bearings and axle bearings while you have it apart.