Strange things you find trying to fix a leak

[AtoXS]

So I was trying to solve the usual left side cover leak. I figured it was the pushrod seal so I replaced that, but the leak persisted. After pulling the cover off again I realized it was coming from the sprocket. The sprocket was super loose so I tighten it up and put the cover back on. I took it for a long ride and it still leaked a ton of oil so again I pull the cover off, this time I pulled the sprocket as well to inspect the seal and this what I found. Surprisingly I've run it this way several hundred miles without any real problems although I also don't know differences I should expect now that a factory sprocket is back on there. I haven't checked to see if the leak is fixed though I doubt it since there was no difference in the thickness of the 510. Anyone ever experience anything like this? It just seemed so odd since I've never really heard XSs being run with a 510 only a 520 or 530.

 

[TwoManyXS1Bs]

??? A 510? First I've heard of that one...

 

[AtoXS]

Yeah right, that's why I thought it was worth posting just because it was so odd.

 

[TwoManyXS1Bs]

... there was no difference in the thickness of the 510...

Might have been a new guy on the factory line (or too much lunchtime saki), and accidently punched a "1" instead of a "2".

Kinda rare, like those 'double die' coins...

 

[AtoXS]

Was Sunstar ever a parts supplier for Yamaha? I know the PO claimed that one of the two bikes I got had performance upgrades, but considering the condition they were in I pretty much called BS, though if this motor was ever hopped up it was either done piss poor or passed it prime. I suspect the former...

 

[XSLeo]

The shaft the sprocket goes on has a certain amount out past the spacer. This amount allows for a 3/8 inch sprocket. That's how thick a 530 is. They used to make 52 sprockets this thick at the center then reduced it to 1`/4 inch at the teeth.
The ones sold now are just a 1/4 thick all the way. This means you need a 1/8 inch thick spacer to put between the sprocket and nut.
On a 510, if that's possible would only be 1/8 inch thick.
Never seen one of those on anything but a bicycle.
With a new 530 sprocket It should be fine.
The sprocket pushes on the end of the spacer, the spacer pushes on the bearing race of the shaft bearing. The nut applies the pressure to keep oil from seeping in between the bearing and spacer, spacer and sprocket.
Leo

 

[5twins]

..... and that means your sprocket nut needs to be very, very tight, like 90 ft/lbs tight. You're trying to seal metal to metal surfaces in several places.