Petcocks leaking despite rebuild??

[SteveO]

Yes, I am trying like hell to keep the Octy. I hate to change anything from stock ...... but I am almost ready to say "the hell with it" and go Gravity.

However, be it Gravity or Octy, that doesn't explain how gas gets in the oil with the Petcocks off!

[Radioguylogs]

Leaking carb float needle valves are part the problem.

[soccer4m]

Mike is right

The float needles, are leaking, could be one or more. It doesnt matter if you have octy or no octy,,,the only way there is gas in the oil is if your needles are leaking. HIGHLY SUGGEST GET RID OF THE OCTY,,,just put in straight lines to the carbs with filter,,,,take off carbs, clean or rebuild the float needles,,,,after doing that hold carbs upside down and blow through the gas line,,,,if ANY air goes in the needle is leaking. Usually you can hear which one is leaking,,,then it time to redo that needle until no more air can pass. Also check the carb gasket to see if it overhangs near the float, its a close fit and maybe a thin razor trim of any overhang. All of us have had to go through the xs carbs and leaking gas has one cause...also change oil.......keep us informed,,,Mike in Sunny Diego

[soccer4m]

multiple problems

I was responding to the gas in oil problem, but noticed there are multiple riders with differing problems,,,got lost in the thread.......
1. oil in gas,,,,float needle/s leaking
2. petcock leaks.....petcock gasket/o ring problem
3. octopus.....PIA,,unless new,,,,recommend toss it far away and connect straight gas lines with filter

[MPittma100]

Good idea

To put a 2x4 under the front tire when bike is parked for a lengthy period of time. Doing this will prevent fuel from entering the cylinders. If there is a leak, fuel will come out of the air box and/or pods instead.

[Bonz]

How much gas is in your oil? Your needle seat o-rings could be shot and leaking fuel from the bowls into the crankcase. That's a decent amount of fuel you would probably smell. Unless the 79 carbs are pressed in seats and can't be removed, then you won't have o-rings.

Your petcock isn't the problem. If the needles are sealing and the needle seats are not leaking (if there are o-rings), then no fuel would get past even with the worst petcock.

Also your needle tips could be crudded up like has been said.

You have 79 carbs, are those the brass tipped float needle? Possible to retrofit with the rubber tipped ones?

[jetmechmarty]

Yes, I am trying like hell to keep the Octy. I hate to change anything from stock ...... but I am almost ready to say "the hell with it" and go Gravity.

However, be it Gravity or Octy, that doesn't explain how gas gets in the oil with the Petcocks off!

OK. To have gasoline in your oil under this condition:

1) You must have leaking petcocks.

2) You must have a leaking vacuum shutoff valve (octy).

3) You must have one or more leaking float valves.

They're going to have to be addressed individually. As far as the vacuum shutoff goes, in your case, removing it should make matters worse. I've put about 90,000 miles on my bike with a vacuum shutoff on it. It has failed to close, but it has never caused failed operation of the motorcycle. It appears the kit for those and the vacuum petcocks has the wrong size o'ring. My vacuum shutoff works fine since I corrected that, but I almost always park the bike with petcocks OFF.

I rebuilt my petcocks from a kit and they've been fine for a long time. Quality control on those is not likely as good as OE. One petcock takes considerably more force to move than the other. I installed mine with rubber lube. Dielectric grease might be good for this.

Helpful info here:
https://www.xjbikes.com/forums/threa...-w-pics.25058/

[Bonz]

If his tank does not leak when it's off the bike it won't leak while it's on the bike. His issue is with his float valves in the carburetors and the residual gas in the fuel lines and bowls is what's getting in the oil. There is no other possible way.

[ThrottleJunky]

I absolutely despise the gas in oil thing that happens with these bikes. It first happened so I rebuilt my petcocks and all 4 carbs and it still happened again. The real bummer was that I didn't even know there was gas in the oil and I had run the bike a few minutes to move it.

I changed the oil, drained the fuel tank and stored the bike with the tank and carbs empty. I think a separate shut off or a different style petcock is mandatory for me, for peace of mind. I think in my instance I may have a float hanging up or something, but at least a real shutoff would prevent it from happening when sitting.

[Bonz]

You still would drain whatever is in the carb bowls into the crankcase. A petcock or auxiliary shut off unfortunately doesn't fix it. Just do a full take a part of the needles and seats and get those in good shape. It also could have nothing to do with your needles and seats. The o-rings sealing the needle seats go bad or can get pinched when you're pushing the needle seats back in and that's where my problems always came from. Mine were wearing out/deteriorating from age, they just don't last forever.