vacuum petcock no operating properly

NewHavenMike

NewHavenMike

1976 XS360C
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Hey guys, I just want to see if this is something that has been happening withothers who also have the vacuum operated fuel petcock.

I tore the petcock down to clean and rebuild it, I am working on finishing the fuel related stuff on my bike. Well, I ordered a rebuild kit from MikesXS and I installed it today. I wanted to test the vacuum operation so I used a hose and hooked it up.. OK, seems diaphragm is moving, but doesnt seal off the main fuel intake passage while its in the "on" position. So I took the diaphragm off and compared it to the old one, seems the same....

I rested the old diaphragm in the hole and it seems like it sits a little higher than the new one. The new one doesnt push in enough to close the fuel intake. Its really close though.

Anyone else have this problem?
 
Xschris, that petcock comes ready to go with the gaskets and all?

Im kind of annoyed because I spent around $45 to get the rebuild kit and I can't return "used" gaskets.

I knew I should've gotten the manual one instead of a rebuild kit! The vacuum petcock looked super clean too it just had dried gaskets.

Edit. I didn't notice that there was more than one pic on the EBay page.. seems like that manual petcock is ready to bolt up out of the box.
 
It is definitely a good idea to use an external fuel filter with both original and manual petcock. I use one on my bike.
 
It is ready to go other than tank bolts and the sealing washers. I would replace yours if they are old. Yes I use an in-line fuel filter. But no filter on the petcock tubes as they tend to pop off and are cheap plastic.
 
@Xchris, does that mean you don't have a reserve system? I thought that inside filter doubled for reservoir, or do you use a 1 inch brass tube or something?
 
These type petcocks have a on and reserve setting on them. There is a long and short brass tube on them.
 

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