79 XS750 breather puking oil?

GuitarGuy1996

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Hey guys, like the title says, I've got a 79 xs750 that I just got running. I bought it as kinda a basket case but finally took it for the first ride yesterday. Among other things, my biggest problem with it now is at any sustained higher rpm (by higher, I mean like 3k and up) it pukes oil out of the crank case breather and a lot of it. I made it maybe a mile yesterday, noticed it, and pushed the bike back home. Partially because it died and wouldn't start but I think that's more of a carb tuning/jetting thing. Any help on this would be great. Thank yall.
 

5twins

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I'd take the breather off and make sure it hasn't been "gutted". There's supposed to be a baffle plate in there. Other than that, if it's the older two outlet breather, there's supposed to be rubber reducer plugs in the ends of the outlet pipes to reduce the outlet size down to about 1/8" .....

BreatherPlugs.jpg


You could also "upgrade" it to the later single outlet breather assembly. It's outlet hole has the reduced size built in .....

Late Breather.jpg
 

GuitarGuy1996

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Thanks man! Mines a single outlet. Also, I just did leak down and compression tests on all 3 cylinders and the pcv was the only thing leaking that I could see and the compression is 131 to 137 psi depending on the cylinder. I'll tear into that vent and see what I find. Hopefully it's not rings.
 

5twins

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Three cylinders? Is this the 750 triple? If so, I'm not familiar with it's breather set-up. The info I provided applies to our 650 twins.
 

GuitarGuy1996

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I think that breather tube goes to the factory air box that I don't have. The previous owner switched it to pod filters and ditched the old stuff. Honestly I would've done the same thing but yeah... I'm kinda wondering if I over filled it the more I look at it. Some stuff says the capacity is 3.4 quarts, some says 4.5 or something and I know I would've went with the higher number thinking i was being on the safe side.
 

GuitarGuy1996

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Sorry for taking so long but I finally got a bit to work on this thing. I'm not 100% sure this is the issue but I just drained the oil and I'm not at all sure how this happened but over 7 QUARTS came out!!!!! I really can't believe I put that much in it but I somehow must have! My oil pan holds 7 and it's overflowing now after draining the oil. I haven't even pulled the filter off, so add another half a quart or so for that? Holly crap!
 
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