sudden petcock change

[DeanR]

Replaced petcock discs last year and everythings been functioning great until this weekend. I've gotten into the habit of usually turning the petcocks to off when I shut down. All of a sudden it looks like the Octopus is leaking gas when they are in the Off position! I have to keep them on when parked or gas flows from some part of the octopus. The off position is now turning off only the rearward petcock tubes(1&2)and initiating the leak at the petcock by allowing the front tubes(3&4) to flow. The on and res positions turn off the front tubes(3&4)and stops the leak. All four will now not all turn off at the same time so I can't remove the tank with gas in it. I'm confused!!!
The bike is running fine.
80 SG so no vacuum control petcocks.

[DeanR]

Still haven't figured out this *^%@^! plumbing change and I'm getting gas all over the place trying to trace this problem. Can't ride the bike or take the tank off yet. Please HELP!! and let me know if my description wasn't clear or didn't make sense!

THANKS

[Dragonrider]

Quick question...are you sure you are in the off position (Yamahas are backwards from everybody else)?

The lever should cover the "off"...in other words, the lever is the pointer...

If you're doing that right, your only option is to pull a line and let the tank drain into a bucket or such...then pull the petcocks apart to rebuild.

Best of luck!

[DeanR]

Yes, I'm sure I have the levers correct. I'm thinking that this could be an octopus problem. Both petcocks have worked perfectly until Sunday, now simultaneously they don't after having ridden 400 miles over the weekend!

[TopCatGr58]

Hey Dean,

Get a spare gas can, possibly some spare hose, and some rags, and just pull the hoses off and drain the gas into the spare tank. Then take the tank off and pull apart the petcocks. Sounds like the rubber holed washer has gotten dislodged, twisted, or broken, so it's not sealing properly!

However if the Octy is leaking, it, too, could be faulty, may need to pull it out and apart also. Check all hoses for cracks! Are you using any clamps to secure the hoses to the fittings?

Roll the bike outside so that the spilt fuel will evaporate quickly!
T.C.

[DeanR]

Hi TC
Drained and took the tank off an hour ago. Everything looks great on the outside. Yes I do clamp the hoses. I'm gonna put some gas back in in the morning to check petcocks only (with the octo and everything else out of the picture). Doesn't seem that both petcocks would malfunction at the same time and I did the rubber discs last fall. Never dealt with the octo tho. What can happen to that and are there replaceable parts in there? Any problems with taking it apart? Thanks once again!!!
Dean

[TopCatGr58]

Hey Dean,

The petcocks have that wavy washer, and if it's not very tight fitting, it can allow the rubber valve to rotate inside, it's not supposed to, and that can screw up the seal and valving action. So take the petcock apart first, and look to see if the rubber valve isn't shifted out of place?

The Octy has a rubber vacuum controlled diaphragm that can be replaced if found defective. You can test it's function by applying suction to it, and see if it flows, and doesn't when suction is released.
T.C.

[Dragonrider]

Doh! Just been re-reading your post....

"gas leaking from some part of the octopus"

Gas is actually leaking FROM the octopus? You, for sure, have a blown diaphram in the octopus. You can by a new octopus...I had bad luck with the aftermarket rebuild kit...the plunger is not the right length and it won't turn off the fuel.

Next, your petcocks should turn the gas off in the "off" position no matter what the octopus is doing. You need to replace the rubbers and make sure the little springy washer thing is in, tight (may have to bend it a bit)...The rubber things are fine out of the rebuild kit....

Note that it may not be both petcocks...if everything is routed right, there is crossover in the octopus....one petcock on will let gas out the other's lines if pulled loose...

[DeanR]

Well, with the tank off, both petcocks operate properly. On and Res turn on 1 & 2, Prime turns on 3 & 4 and Off turns both off.

It would appear that the octo is the culprit. However, Dragonrider, you thought the petcocks should turn off no matter what the octo is doing. But 3 & 4 were being turned on when tank was on the bike on off! Thoughts?

Regarding testing my octo. It is in my hand with the back removed. The rubber pieces look intact and the center plunger thing operates. How else can I diagnose it?
Thanks!!!!

[TopCatGr58]

Hey Dean,

You'll need to put it back together, and then connect some hoses to it to be able to flow fuel into it, and also connect the vacuum tube. Then turn on the fuel so that it's going to the Octy. It shouldn't leak at all right now! IF it does, then it's not sealing!

Then, apply suction to the vacuum line, and fuel should now flow out of it, but should stop once you stop applying vacuum. IIRC there's a spring inside, it too may have gotton sprung not applying enough pressure to properly seal? I haven't had one for decades!
T.C.

[DeanR]

Everything's back together. Petcocks shutting off properly at present. With engine running, petcocks on, there is gas shooting out of octopus at a place where there is a small 1/4 in channel in the egde of the center plastic plate between the rubber pieces.
Something is apparantly not sealing correctly but I can't visualize it. Sure wish I had a digital camera!

[John]

Just get rid of the damned octopus. I haven't used one in years.

[DeanR]

Expected that suggestion from someone! I'm gonna look back through threads to find out how to do that. Am I correct that you then have to shut off petcocks every time? And if you forget?

[TopCatGr58]

Dean,

I've run without it for years. And as long as your carb's float needle valves are working well, then IF you forget to shut off the gas, there is NO problem, cause the carbs will stop it, and that's that! It's ONLY if your float needles aren't sealing properly is when the gas will flood the carb, and then possibly get into the cylinders and oil. Once you start using it without the Octy, you'll quickly learn the habit of turning them off, just like locking your car when you get out!

You can use the "T" connectors to join the outlets of the petcocks so that you don't look your Prime and reserve. Just turn the "T" so that the two lines from the petcock are joined at the "T" on one side and the bottom of the "T", which will make a 90 degree angle vs. the 180 degree across the top, so less of a bend and therefore reducing the crimping/kinking of the lines. Then run the remaining outlet to one of the fittings on the carbs. While you're at it, put an inline filter between the carbs and the "T" connector. Then turn the petcocks to ON to drive, and then to OFF when you shut it down, that's it!
T.C.

[Dragonrider]

Dean,

There is a diaphram in the octopus. If gas is leaking out the channel, the diaphram's shot.