free website stats program Vacuum petcock | Harley Davidson Forums

Vacuum petcock

Beer Hound

Member
Howyadoin? I'm a new guy here so I hope I posted in the right place. I'm working on a Brother's 96 fxstc. I had to rebuild the carb, replace the carb/ intake seal, fuel lines, etc. The petcock was also leaking and HD has no rebuild kit for it so I bought a aftermarket one. It is not vacuum actuated and I was told to plug the hose. Do I plug just the hose to the petcock or Carb, Diaphragm, and pet cock? It's a Drag specialties petcock, he couldn't afford much. Thanks!
 
Sounds like a plan, do not want a vacuum leak, so plug the hose or trace all the way back to the fitting, cap or thread in block off and your done. You will have to remember if long term storage longer than a week to turn petcock to OFF and REMEMBER to turn it back ON as part of your "FINE-C" (Fuel petcock, Ignition, Neutral, Engine Kill & Choke) start ritual, that vacuum operation allowed you to forget about the fuel petcock...no more.
 
There should be no fitting on the new petcock for the vacume line
the vacume line still attatched to the carb should be plugged easiest way to do that is to screw a self tapping screw into the end of the vacume line

Brian
 
You are actually better off with the manual petcock. Just get in the habbit of turning the valve off when you stop, and turning it back on when you start!

As Brian said above, cut the vacuum hose (or better yet, replace it) so it is just a short stubby bit long enough to squirt some Permatex PVT or similar in the end, and then put a sheet metal screw in to seal it. You are only trying to prevent a vacuum leak at the carb base or where ever that nipple is at the intake manifold. Shouldn't have anything left at the tank.

TQ
 
I told him if He didn't remember to turn on the fuel He would have some short rides. I bought vacuum line caps that go over the line or stem and blocked the line that would have gone to the petcock, should I leave the carb hooked up to the diaphragm or block it off totally? There are electrical lines attached to the diaphragm. Thanks
 
The bit that has a vacume line to it and some wires attatched is the voes which is part of the advance system if you take it out of the system then you may have poor running

Brian
 
The bit that has a vacume line to it and some wires attatched is the voes which is part of the advance system if you take it out of the system then you may have poor running

Brian

What Fin said:D
 
Vacuum petcock was a good idea that just did not work out.
HD was ahead of the game with it Carb bikes are gravity feed fuel the Government was looking at requiring different types of safety shut off to prevent fuel leaks.
Now with all bikes being EFI it is not an issue anymore.
Everyone I know that had a Vacuum petcock fail just got rid of it.

My Bro told me HD had a recall in 98 for the pet cock, he was on a road trip when it went at that time. Harley now tells you to replace it with pingle ( dealer depending).

and thank you and any other service personal for my Freedom!
 
Back
Top