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92 r100r petcock removal

tinkerer

New member
i have a little seepage from one the pet cock at the tank connection right side
i am thinking of rebuilding them
i tried to snug the nut on the leak but it was tight and didn't want to force anything
any tricks for removing the pet cocks?
 
Could you take a picture of one of the petcocks? Typically, there is a large hex nut holding the petcock on. IIRC the nut turns off like normal - righty tighty, lefty loosey. Note that the threads on the tank and those on the petcock are different directions. After removing the nut on the bottom side to remove the fuel line, use an open wrench to hold the petcock steady while another open end wrench is used to turn off the large nut. To reinstall, you need to start both sets of threads at the same time...that way the petcock is drawn up at the same time as the large nut tightens against the tank stub.

I had a persistent leak on my /7. After trying everything, I noticed that the tank stub had some minor imperfections...the end wasn't perfectly flat. So, I took a file and dressed it. No more leak.
 
If you're removing the petcocks, and haven't made a periodic maintenance point of doing so, plan to flush out the fuel tank. If yours is like my '91, there'll be some amount of tank lining on the in-tank filter screens, and more when you rinse it out. I've recently done petcock servicing on three of the four petcocks that I have on my two airheads, and they're a minor pain, even with a bench vise to hold the retaining cap while you screw the petcock body back on against fairly stout spring pressure. With total replacements only about $40, I'll probably just order a new one or two whenever there's another seasonal %-off sale at Bob's or MAX. Not the "airhead way", I know.
 
thanks for the reply
of course i just filled the tank
but i do own a gas can somewhere
tank flush sounds like time well spent
 
Yeah you can tell by the off colour of the threads and in front face of the tap. It's seeping. As Kurt said, turn it CC to get it off. What is not intuitive sometimes is that that big nut sucks the petcock and tank threads together at the same time so one threads clockwise the other counter clockwise.

Putting them back together involves starting the two at the same time OR threading the nut onto the tank to close to half way and then thread the petcock back on. Then you have to figure just enough slack on the petcock such that when you tighten them together sufficiently they line up properly.

Sounds like a pain but once to do it a couple times it is very easy really. Sometimes you find a red fiber washer in there and sometimes folks just rely one the aluminum washer that is part of the new screens and it forms a good seal for quite a few removals but once they start to seep dressing the tank side as Kurt said can fix that but also adding the fiber washer can sometimes fix the seeping as well.
 
Not the normal threads either!

Just so you know, I'm pretty sure the lower part of that petcock has "left handed" (reverse from normal) threads and it will mess you up and mislead you all the time. Just be careful when you un-screw the petcocks and make yourself familiar with just how they come apart.

Don't force it! If there is no rust or obvious corrosion and it still seems real tight you may be turning it the wrong direction. Sometimes the petcock is fine and its the seal between the petcock and the tank that needs some attention.

If the petcock works OK try cleaning all the seals for mounting it and apply a slim layer of grease on both sides of the fiber washers that act as seals for the fuel petcocks.
 
Putting them back together involves starting the two at the same time OR threading the nut onto the tank to close to half way and then thread the petcock back on. Then you have to figure just enough slack on the petcock such that when you tighten them together sufficiently they line up properly..[/QUOTE

A technique that I like to use is to start the nut onto the petcock 2 turns, turning to the left (CCW) as they are left-handed. Then take a fine felt marker and put an alignment dot on both so that their relative positions can remain the same. Holding both at the same time, turn both together (CW) onto the threaded tank stub the same 2 turns. Now you will have the nut 2 turns onto both ends and the petcock will hang safely. From there, hold the petcock from turning and turn the nut clockwise to draw the assembly together until snug. This method absolutely guarantees that the left-handed end of the nut will smoothly engage onto the petcock. HTH.

Russ
 
And a picture

20160502_102605.jpg

The seal is the copper base of the mesh filter which goes over the two straws.

To disassemble I untighten the nut from the tank with a wrench going clockwise looking from top. At the same time I move the petcock by hand the same as the wrench. A few times I had to use some creeping oil to get it lose.

/Guenther

Edit: It's been a while but I think there is only a right thread all the way through in that nut.
 
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