You would have much better luck going for the 1/2" sprocket P/N 73050/72854 and 1/2" chain. The drive belt is P/N 71270.
Lots of luck... you are going to need it.
I bought a 28 inch bar for my saw and I'm trying to find some chain. I want to keep it original and the parts list calls for 9/16 chain. I wouldn't consider the lcs a true gear drive because it uses a belt off the clutch to drive the gear that drives the chain.
The later Homelite 26CLS used the 1/2" chain...Are you positive that the sprocket you have is for 9/16"?
Either way a new sprocket may be VERY hard to find.
I think the bar that came with my saw is 22 inch. The chain is 1/2" pitch and .063 gauge if I measure it right. The parts list I have only lists 9/16" pitch and .050 gauge. I broke open the 22" loop of 1/2" pitch chain just to see if the gauge would fit the bar. The 28" bar won't take the chain because the groove is too narrow. Do you think the 28" bar could be spread out too accept the 1/2" chain? If so, then I only need a 28" loop of 1/2" chain. Thanks for you input so far.
The only gauges 1/2"(#9 
) and 9/16"(#4) chain was .058 and .063.
There is no economic way to fit the larger chain into the .050 gauge bar.
Are you sure the bar is a correct fit for your
saw?
I'm sure that the 28" bar is correct for my saw because all of the mounting holes line up perfectly with the 22" bar that came with my saw. I'm curious to know where your information comes from on the .058 and .063 gauge, because my parts list says .050. Could this be a misprint or something on my parts list? I thought that 9/16 pitch should have a bigger gauge like .063, but didn't know what the manufacturer was thinking when they built the saw.
My error..
Got to looking deeper and found OREGON made at least 7 different 9/16" chains. #4C,4L,5AC,5AL 6C,7C & 8BC. All used a 9/32 file, a.040 depth gauge setting and a 35deg angle on the top plate. Several were still in the 1971 price list.
clutch, belt, and drive sprocket
Note rubber has been cut-away from portion of belt to reveal cords. If someone wants higher resolution of these pics, e-mail me and I will send them to you. Let me know which ones you would like.
That's OK, I have 2 more complete units. This one is a great display piece. It was used for a teaching aid at my High School. After my shop teacher retired, the new teacher was going to throw it in the dumpster, but the retired teacher heard of his intentions and grabbed it. He saw my display of saws and knew I would take care of it. Makes it worth more to me coming from someone like him. He was one of my favorite teachers.