Harley Davidson Forums

Loading


Hello

Guest

Welcome to the harley davidson forum. Join our discussion today for FREE!

CREATE ACCOUNT

Membership Benefits

Get your questions answered by harley davidson community gurus and industry experts. Exchange your experience with another members. Access full features forum. Get a members discounts for your harley parts & accessories.

Vacuum Petcock?

Engine, Fuel and Exhaust

Reply
 
Thread Tools Display Modes
Old Oct 11th, 2009, 02:27 PM     #1
Moderators
Ride: 2003 Road King
 
Bodeen's Avatar
 
Join Date: Aug 12th, 2009
Location: Central Florida
Posts: 3,841
My Mood: My Mood
Bodeen is an unknown quantity at this point
Vacuum Petcock?

Having never had a vacuum operated petcock apart. Is it possible for fuel to pass through the vacuum line while running if the petcock were faulty? If the petcock were faulty ie: bad diaphram isnt the fuel supposed to shut off?

TIA,

Bodeen
Bodeen is offline   Reply With Quote
Old Oct 11th, 2009, 03:15 PM     #2
Wise Member
Ride: 0
 
Join Date: Jun 21st, 2007
Posts: 26,212
My Mood: My Mood
glider is on a distinguished road
Re: Vacuum Petcock?

The purpose of the vac petcock is to close off the fuel when the engine stops from lack of vacuum. The restart is accomplished by the fuel in the float bowl until the engine draws vacuum and opens the petcock. More problems for some than they are worth. Many have changed to a Pingle manual petcock or retro fitted to the regular HD mechanical petcock.

Most times when they fail the engine just quits from lack of fuel.
glider is offline   Reply With Quote
Old Oct 11th, 2009, 04:00 PM     #3
Retired Moderators
Ride: 2005 FLTRI
 
Join Date: Aug 28th, 2009
Location: Suwannee, Fl
Posts: 4,782
My Mood: My Mood
HDDon will become famous soon enoughHDDon will become famous soon enough
Re: Vacuum Petcock?

Glider has it right, get rid of the vacuum petcock and go for a Pingle.
HDDon is offline   Reply With Quote
Old Oct 11th, 2009, 04:10 PM     #4
Moderators
Ride: 2003 Road King
 
Bodeen's Avatar
 
Join Date: Aug 12th, 2009
Location: Central Florida
Posts: 3,841
My Mood: My Mood
Bodeen is an unknown quantity at this point
Re: Vacuum Petcock?

Thanks guy's
I figured if the diaphram were torn it would close off fuel supply.
I was thinking that it would be possible for fuel to flow through the vacuum line to the carb adding extra fuel to the mix. I saw the self help section and the Pingle link. Proud of those jokers!

Bodeen
Bodeen is offline   Reply With Quote
Old Oct 11th, 2009, 04:10 PM     #5
Retired Moderators
Ride: 2004 Sportster XL1200R
 
NEWHD74FAN's Avatar
 
Join Date: Aug 24th, 2008
Location: Camarillo, CA
Posts: 8,276
My Mood: My Mood
NEWHD74FAN is an unknown quantity at this point
Re: Vacuum Petcock?

Maybe I'm a little...eh..."-new fashioned" here, but the vacuum petcock is a safety feature to prevent those of us who do not shut off the fuel when they park the bike for long periods...not that any of us "-old timers" would ever admit to anyway. There was a thread about a suitable replacement, for the rubber diaphragm for something like $5.

Sorry, I just had to get it off my chest, and yes a replacement vacuum petcock is about the same price as the full Pingle replacement, but hey it's your decision.
__________________
* Please click "Self Help Tips" tab for service tips, diagnostic codes & such * ;o) * Please click "Search" tab and keywords to find related threads *

Last edited by NEWHD74FAN; Oct 11th, 2009 at 04:12 PM.
NEWHD74FAN is offline   Reply With Quote
Old Oct 25th, 2009, 12:40 AM     #6
Warming The Wheels
Ride: 07' FLSTC
 
Join Date: Aug 2nd, 2008
Location: Ore-gon
Posts: 128
My Mood: My Mood
nogoslim is an unknown quantity at this point
Re: Vacuum Petcock?

What years did harley put vacuum fuel shut off valves on their bikes, if at all? Did any efi bikes ever use a fuel shut off valve, vacuum or mechanical? If you put a fuel shut off on a newer e.f.i. bike, would it cause any damage to the regulator or fuel pump?
nogoslim is offline   Reply With Quote
Old Oct 25th, 2009, 07:47 AM     #7
Moderators
Ride: 1994 Road King FLHR
 
SledDog's Avatar
 
Join Date: Jun 21st, 2008
Location: Florida
Posts: 1,662
My Mood: My Mood
SledDog is on a distinguished road
Re: Vacuum Petcock?

You can replace the vacuum petcock with a high flow "aftermarket" petcock for about $30.00.

The OEM style vacuum one will cost you about 85 buck. I replaced the vacuum one on my road king with a high flow aftermarket unit last year and have had no problems. But I'm used to running off/on the gas. I did it even when I had the vacuum one on the road king.
__________________

Please stop by the "self help section" for maintenance tips, diagnostic codes and much more.
click me >>Self Help Information and Tips<< click me
SledDog is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Similar Threads
Thread Thread Starter Forum Replies Last Post
Vacuum petcock Beer Hound Engine, Fuel and Exhaust 8 Oct 1st, 2010 10:21 PM
vacuum assisted petcock bigd66 Engine, Fuel and Exhaust 5 Aug 28th, 2010 07:50 AM
Vacuum Fuel Petcock Recall glider. Fuel and Carb Related Issues 2 Jan 30th, 2010 04:45 PM
Vacuum pics or diagrams The Rook Sportster Models 0 Oct 1st, 2008 03:24 PM
Vacuum To Mechanical Petcock glider. Fuel and Carb Related Issues 0 Jul 18th, 2007 10:09 AM