Gokart help on sprocket

[David5952009]

I have a small kids gokart think it’s 5.5 hp and I put a new clutch on it and it has a #40 size chain, but the sprocket on the gokart is way different what sprocket would fit on those that I can use this #40 chain here’s a few pictures of the stock sprocket help thanks

 

[madprofessor]

The 4 in #40 represents 4/8" size, in other words a 1/2" size.
The 3 in #35 likewise means 3/8" size, big difference between the two. #35 is the most common in use, more than sufficient for your motor.
Go to "gopowersports.com", it has a chart for you to see the different chain sizes. On their website, click on gokart parts. A dropdown menu to the left lists all the categories for gokarts, click on "Chains and Guards". The chart will show you how to measure your chain and sprockets to determine what you need to use.
Can you remove and replace the sprocket built onto the clutch?
Note: To fit your chain right, a master link might get you close. If sloppy, there is a half link available, also called an offset link. Same website.

 

[Denny]

Or you could just simply slide the engine to tension the chain if possible.

 

[madprofessor]

David, what Denny just said about adjusting the chain tension is true of course. I suggest the master and half links under the assumption that you'd be splicing the 2 ends of a piece of chain together (master link), and that the ability to slide/adjust the chain tension enough is not there.
If finesse getting the chain to a good length is required, any master or half links are just a necessary evil, and one to avoid insofar as having more than 1 of each maximum if possible.
Running 2 masters between a long and a short piece of chain myself, but only because I'm not enough of a purist to pay for another 10' roll of chain to make a long enough single piece.
EDIT: If you only need let's say 2 links to make a long enough chain, 2 master links consecutively won't do it. A master link needs a male link end (the inside pair of plates w/roller that fit between a pair of outside plates) to attach to at both ends of itself, as a master is 2 female ends (and they have the connecting pins attached to them). 2 masters won't link together, must have 2 male link ends between them.
That's where a half link can be very useful, if you don't mind the use of them. A half link is an open female end (no pin attached, it's included, you stab it in, a tiny shear pin keeps it there) and a male end. You can string as many of them together as you like, but 1 master is required.
Note: I recommend only installing half links with the male end leading the female end, not sure why, just a quirk of mine.