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post #1 of 15 (permalink) Old 06-02-2012, 06:52 PM Thread Starter
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Ticking Petcock

After working on my bike for the last few months, I've noticed a loud ticking sound that is most prevalent at idle, but is also intermittent. It really sounded like something in the top-end of a cylinder and I have been somewhat freaking out ever since.

Today I think I narrowed it down to the petcock. It's the original, and has never been rebuilt according to the documentation I have, so I am thinking that is the case. I read a thread about somebody else noting they had a ticking petcock, so that gives me some hope. I couldn't hear the ticking in the cylinder with the screwdriver method, but it is LOUD AND CLEAR on the tank. I even took my carabiner that I keep my keys, tapped on the cylinder heads, and could not get the sound to be that loud in the tank. I also felt the tick a bit when I had my fingers holding the petcock (there is a joke in there somewhere).

So, would a simple petcock rebuild take care of this, do you think? I don't think it's detrimental, but it is annoying. Scared me to death thinking I may have upper chain issues, etc.

1986 Kawasaki Vulcan 750
NGK Iridium Plugs #7803/DPR7EIX-9
Duralast Gold ETX15 AGM Battery
Coastered & Shaved
TOC MCCTs
Metzeler ME880 [110/90-19, 170/80-15]
Balance Dampers Replaced
Tuxedo Mod
Rebuilt Forks w/ Progressive Springs
V&H Cruzers
VN750.com Grill Cover
Meanstreak Seat
Emgo 23-92411 Handlebars
MOSFET FH012AA R/R


1990 Kawasaki Vulcan 750

1998 Honda VFR800 FI

2014 Honda VFR800F

1989 Pontiac Firebird Formula 350
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post #2 of 15 (permalink) Old 06-02-2012, 06:59 PM Thread Starter
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I just read up on another post with a possible fix from Dave. Quote is below. Here is the post. I'll reply with how it goes. Sorry for posting prior to searching more in-depth.

Quote:
Originally Posted by DavesVulster View Post
Fixed! Hallelujah . I ran a T (actually looks like an F) and vac lines to both carbs. My theory was that since only one line was used to supply vacuum the valve was chattering due to the pulse of only the one cylinder pulling. Since both cylinders suck opposite each other, using both on the petcock valve applies more consistent vacuum keeping the valve stable. Worked great! Was so happy I took it for a half hour ride in the rain, ha ha. Hope this helps someone else.
Dave.

1986 Kawasaki Vulcan 750
NGK Iridium Plugs #7803/DPR7EIX-9
Duralast Gold ETX15 AGM Battery
Coastered & Shaved
TOC MCCTs
Metzeler ME880 [110/90-19, 170/80-15]
Balance Dampers Replaced
Tuxedo Mod
Rebuilt Forks w/ Progressive Springs
V&H Cruzers
VN750.com Grill Cover
Meanstreak Seat
Emgo 23-92411 Handlebars
MOSFET FH012AA R/R


1990 Kawasaki Vulcan 750

1998 Honda VFR800 FI

2014 Honda VFR800F

1989 Pontiac Firebird Formula 350
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post #3 of 15 (permalink) Old 06-02-2012, 09:15 PM
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That might do it. The sound would be nothing to worry about, let's you know it is working. The diaprahm inside the petcock slides open when there is vacum on every intake stroke on the one cylinder and then closes on the other 3 strokes. Dual vacum would open on 2 strokes, it would actually open and close much more rapidly, but kind of stay open all the time while running cause the spring isn't strong-fast enuff to close.
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post #4 of 15 (permalink) Old 06-03-2012, 01:49 AM Thread Starter
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It is nice to know that it is nothing major, but it is somewhat unsettling as it is the only thing I can really hear over the exhaust. With the ACCTs gone, the noise really went down a ton!

I'm going to do this tomorrow in an effort to quieten down the ride. I want to throw in some 42 pilots as I think 40 is too small, and I need to swap the front jet to 142 I think.

1986 Kawasaki Vulcan 750
NGK Iridium Plugs #7803/DPR7EIX-9
Duralast Gold ETX15 AGM Battery
Coastered & Shaved
TOC MCCTs
Metzeler ME880 [110/90-19, 170/80-15]
Balance Dampers Replaced
Tuxedo Mod
Rebuilt Forks w/ Progressive Springs
V&H Cruzers
VN750.com Grill Cover
Meanstreak Seat
Emgo 23-92411 Handlebars
MOSFET FH012AA R/R


1990 Kawasaki Vulcan 750

1998 Honda VFR800 FI

2014 Honda VFR800F

1989 Pontiac Firebird Formula 350
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post #5 of 15 (permalink) Old 06-03-2012, 06:29 PM Thread Starter
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I just went out and did this mod, and man, it's been the best thing I've done since the ear-shave. It really stabilized my idle, and removed that nasty clanging noise.

I am really surprised. I wonder if the vacuum off one carb doesn't pull enough gas for an ear-shave setup? When I pinched the secondary vacuum, my idle got a little rough again, let off, and it was stable as can be. Either way, hooray! Pics are below...

Left (Petcock) Side


Right (Secondary) Side


It doesn't even look bad, honestly. I just need to take a Sharpie to the T fitting.

1986 Kawasaki Vulcan 750
NGK Iridium Plugs #7803/DPR7EIX-9
Duralast Gold ETX15 AGM Battery
Coastered & Shaved
TOC MCCTs
Metzeler ME880 [110/90-19, 170/80-15]
Balance Dampers Replaced
Tuxedo Mod
Rebuilt Forks w/ Progressive Springs
V&H Cruzers
VN750.com Grill Cover
Meanstreak Seat
Emgo 23-92411 Handlebars
MOSFET FH012AA R/R


1990 Kawasaki Vulcan 750

1998 Honda VFR800 FI

2014 Honda VFR800F

1989 Pontiac Firebird Formula 350
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post #6 of 15 (permalink) Old 06-03-2012, 07:35 PM
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Nice touch Tanner...Wolfie approves !!!!
And those tees do come in black as well...used in automotive vaccuum applications. Mostly found on 70s-early 80s US cars.
I'd just plugged my other one with a bolt, but dont recall any petcock "rattle"...I am however gonna do this to mine. Just a more professional look as well. Well done Kemosabe....



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post #7 of 15 (permalink) Old 06-03-2012, 11:23 PM Thread Starter
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Quote:
Originally Posted by Wolfie View Post
Nice touch Tanner...Wolfie approves !!!!
And those tees do come in black as well...used in automotive vaccuum applications. Mostly found on 70s-early 80s US cars.
I'd just plugged my other one with a bolt, but dont recall any petcock "rattle"...I am however gonna do this to mine. Just a more professional look as well. Well done Kemosabe....
Glad I got the official Wolfie Seal of Approval™ there! I just back from a good hour and half ride (longest since I've done all the engine pulling, stator swapping, etc), and it was a dream! She purrs like a kitten at stop lights, and looks good doing it. She ran like a bat out of hell on the freeway. Some have noted a dis-taste for the "drone" of the V&H Cruizers at freeway speed, but I liked it. Maybe I am just happy that the bike is (finally) happy.

I still get some popping in my front exhaust on decel, but I'll work on the pilots, etc, here next weekend or two.

Let us know how your mod goes.

1986 Kawasaki Vulcan 750
NGK Iridium Plugs #7803/DPR7EIX-9
Duralast Gold ETX15 AGM Battery
Coastered & Shaved
TOC MCCTs
Metzeler ME880 [110/90-19, 170/80-15]
Balance Dampers Replaced
Tuxedo Mod
Rebuilt Forks w/ Progressive Springs
V&H Cruzers
VN750.com Grill Cover
Meanstreak Seat
Emgo 23-92411 Handlebars
MOSFET FH012AA R/R


1990 Kawasaki Vulcan 750

1998 Honda VFR800 FI

2014 Honda VFR800F

1989 Pontiac Firebird Formula 350
thtanner is offline  
post #8 of 15 (permalink) Old 06-04-2012, 01:11 PM
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I have had a strange idle issue ever since I got this bike. It is more of an annoyance than a real problem...I may do this just to see if it cures the rough idle issue.
thanks for sharing!
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post #9 of 15 (permalink) Old 06-16-2012, 02:06 PM
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I had the same problem. I never would have guessed it would be the petcock if I didn't read this post. Thanks!

I solved it by putting a restrictor in the vacuum line, close the the front carb. Just a small pieces of plastic with a tiny hole in it.

No need for an extra hose.
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post #10 of 15 (permalink) Old 06-21-2012, 10:05 AM
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stupid question

Hey new to the whole Vulcan world and a bit of a newbie when it comes to the cruiser stuff but i have a 85 VN 700 and was wanting to try this mod but i the vac line coming off of my right carb goes to this vac diaphram like thing with two big hoses coming off it what do i need to do about that . thanks for the help
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