81 special leaky petcock

[Dads11special]

Here's the scenario - I noticed fuel dripping from the airbox and engine feeling like it is flooding out on # 1 or 2. I pulled the drain plug off #1 bowl with petcock in off position. After the initial drain of the bowl, fuel kept flowing no matter what position the petcock was in. I did the same on #4 bowl and fuel did not flow when in the off position.
I do still have the octopus. I also pulled and checked all 4 plugs which all looked normal - light tan and dry. ( plugs are new - only 80 miles on the new plugs)
Any help is appreciated. Bob

[TopCatGr58]

Hey Bob,

With the float bowl drain off, it can't fill...float can't float to stop the flow, and so yes, you can see that the petcock AND Octy are leaking, continuing to drip into the carb. This is provided that you have the hoses correctly routed.

However, also sounds like your float needles aren't working properly in carb #1, cause IF they were, then the carbs wouldn't flood no matter what the petcock or octy was doing. I had a float that wasn't working right due to a slanted float pin, badly repaired float post! Rebroke and fixed the float post, and that carb stopped leaking and flooding, ran much better!
T.C.

[mro]

I was going to point you to a rebuild kit for the specials.
Only I can't find it
Was only $20.00 and did 2 petcocks.
Bikebandit has kits for the petcocks.
There price $25.00
Little more and can get after market new petcocks.
Vac part on the octopus is still available.

You'll need to see why gas was getting by the float needle/valve too, so may need to clean carbs and replace needle and seat.


mro

[mro]

http://cgi.ebay.ca/YAMAHA-XJ1100-XS1100-SPECIAL-PETCOCK-REBUILD-%20KITS_W0QQitemZ200191907021QQihZ010QQcategoryZ35597%3Cbr%20/%3EQQssPageNameZWDVWQQrdZ1QQcmdZViewItem

sip...in another post found this.
What you need for petcocks and octopie


mro

[Dads11special]

Thanks for the help. In order to fix this will I need to pull the tank? I've not done this before.

[mro]

I do...
And it really helps when pulling the carbs too.


mro
if you just repair the fuel delivery and not the float needles you run the risk of getting fuel into the crankcase and possible fire.
Gas can leak into the air box and on to the engine even when the engine is running if a float/needle hangs up


mro

[DiverRay]

The '81 uses the "O" ring seal on the seat. You NEED to replace the "O" rings. I would just buy the kits for the carbs, and use the new needle and seats. Any other solution is asking for trouble, IMHO.

[Dads11special]

Update Time. I replaced all parts in the two petcocks and in the octy - small tear in the diaphragm- and NO MORE LEAKS!!!!! However, on the first run, I noticed that it pulls great through 1st and 2nd gears. When I shift into 3rd at about 3800 rpm the engine will stutter as if it is trying to drop a cylinder. If I twist the throttle a little more and then shift into 4th all is well into 5th. Any ideas????
Thanks for the info on where to get the rebuild kits

[TopCatGr58]

Originally posted by Dads11special
However, on the first run, I noticed that it pulls great through 1st and 2nd gears. When I shift into 3rd at about 3800 rpm the engine will stutter as if it is trying to drop a cylinder. If I twist the throttle a little more and then shift into 4th all is well into 5th. Any ideas???

Hey Robert,

The 81's are much less prone to the pu coil wire problem due to less flexing of the timing plate, so I doubt it's the problem.

My question is why are you shifting at such a low rpm??

I would doubt that you're draining your float bowls that quickly running in 1st and 2nd, especially when you're shifting so soon at a low rpm instead of winding it out alot in 1st and 2nd. But it might be, so you could try running on PRIME and see how it behaves.

Also, after rebuilding the Octy, did you test it first by applying vacuum to the valve and see how well the fuel flowed?? Is there any possible air leaks in the vacuum line going to the Octy which could prevent the valve from opening all the way!?
T.C.

[scalded dog]

Hello, can anyone point me to the right place to find the tips on replacing the "octopus", can't seem to find it. Thanks "Dog

[Hired_Goon]

Originally posted by Dads11special
Update Time. I replaced all parts in the two petcocks and in the octy - small tear in the diaphragm- and NO MORE LEAKS!!!!! However, on the first run, I noticed that it pulls great through 1st and 2nd gears. When I shift into 3rd at about 3800 rpm the engine will stutter as if it is trying to drop a cylinder. If I twist the throttle a little more and then shift into 4th all is well into 5th. Any ideas????
Thanks for the info on where to get the rebuild kits

Just been a similar problem except mine was reversed. Had no leaking, but the petcocks were not opening at all. No big problem. Just put it on prime and keep riding. However, on prime was causing me a similar stutter due to flooding on #3 carb.

Pulled carbs and removed float and needle/seat. All looked fine until I was putting it back together. Gave the floats a shake and it sounded like a half full coke can.

Replaced with a spare one and all is good now, stutter is gone.

So, this brings me to suggest checking float levels and floats themselves. COuld just be one set a little bit high.


Now I just need my new petcock kits to arrive from Florida. Finally had to get over my mistrust of ordering from overseas as parts for petcocks here can only be bought individually from Yamaha

[jetmechmarty]

Dog,

As I recall, you ride a standard. You can't find the "octy" because your bike doesn't have one. It's mounted on top of the left carb on a Special.

[scalded dog]

Hello Marty. I have two specials and 2 standards now. I just picked up my second special this week, and wanted to do away with the "O", do you still run the "O", on your special? Later 'Dog

[jetmechmarty]

I replaced my "O" with a new one. I'm happy that way!

[Dads11special]

Where can I find the brass float and a bowl gasket? My #1 carb float has a hole in it and I guess I need to replace it. Also, it does not slide. Since this is my daily ride I need to fix asap. Thanks for all your advice.