Do this and Never Buy Another Petcock

[Rio Wil]

HEHEHE.....well maybe never. I seem to remember this subject from many months or years ago, but can't find it anywhere. I have often wonder if the strong vacuum pulses from the carb was responsible for destroying the diaphragm in the oem (and others) petcock. So I hooked up a fast acting vac gauge to the  petcock vac line and it was just spooky how violent the pulsations were. No wonder it breaks. Then I added in line a vac snubber with about a .027 inch orifice. It moderated the pulsations hughly and still has enough vac to hold the diaphragm open.....as I recall it only takes a couple of inches of vac to to do that. I have a couple of videos showing the with and without snubber. Anyone want to weigh in on this topic, feel free and I need some assistance in uploading the videos. Apparently in postimage it only takes stills..... The .027 size oriface was just a swag as I had some monofilament line that diameter.....seems like a good starting point. Anyone have any experience with off the snubbers that might work? I don't do facebook or utube.....

[Madmike]

Do a search on "vacuum snubber" and there is lots of discussion over time

[98valk]

my original diaphragm failed at about 15k miles.   I put a new one in and installed a snubber, still working fine at 72k miles.

This was back in around '02 I posted about doing this. some followed my lead.

[Jess from VA]

On the other side of things, I seem to remember stories of people rebuilding their OE petcock with the OE rebuild kit, then having to do it again maybe only 2-3 yrs later.   

[psckam]

will any snub work? Looks like an inexpensive solution!

[Jims99]

I was under the impression the oem petcock had the snubber built in. Anyone know if that’s right?

[Rio Wil]

Anyone know where/how I can post a video to be visible here?

[98valk]

I was under the impression the oem petcock had the snubber built in. Anyone know if that’s right?

there is not. I tested it against a snubber installed and snubbers are not small.

[98valk]

will any snub work? Looks like an inexpensive solution!

I used this one 1/8" size

https://www.mcmaster.com/3820K26/

https://www.mcmaster.com/pressure-gauge-snubbers/pipe-size~1-8/

[Bagger John - #3785]

On the other side of things, I seem to remember stories of people rebuilding their OE petcock with the OE rebuild kit, then having to do it again maybe only 2-3 yrs later.   

That would be me.

Then I put a snubber on that particular bike. Is working well so far.

The other Valkyrie I have was converted to a manual petcock (CBR600F2-later). I'm going to install a Dan-Marc shutoff next time I have the bike apart.

[Rio Wil]

I am leaning toward simplicity here....maybe a one inch long piece of 3/16 inch aluminum/brass rod with a bout a .025 hole drilled through it and simply put it inline with the vac tube to the petcock. Hopefully, I can post 2 videos showing before and after....I suspect a smaller orifice of maybe .015 would be even better...

[Bagger John - #3785]

I am leaning toward simplicity here....maybe a one inch long piece of 3/16 inch aluminum/brass rod with a bout a .025 hole drilled through it and simply put it inline with the vac tube to the petcock. Hopefully, I can post 2 videos showing before and after....I suspect a smaller orifice of maybe .015 would be even better...

I got a .015 or so snubber from AutoZone. Will see if I can find details (like a P/N).

[98valk]

I am leaning toward simplicity here....maybe a one inch long piece of 3/16 inch aluminum/brass rod with a bout a .025 hole drilled through it and simply put it inline with the vac tube to the petcock. Hopefully, I can post 2 videos showing before and after....I suspect a smaller orifice of maybe .015 would be even better...

the orifice port is normally half the length of the total snubber length.

[Rio Wil]

Do these links work?



https://imgur.com/eQEAKjv



https://imgur.com/TasdheZ

Its understood that a great deal of the needle fluctuations  is due to inertia of the needle swinging around but the effect of the snubber is obvious....

[Jims99]

Links work. Thanks

[mello dude]

So you just put the snubber in line off the carb vac line to the tank?

[Rio Wil]

Yeah, just cut the petcock vac hose whereever its easy and insert the snubber.  I don't want the bulk of three brass fittings  (hose nipple w/female pipe thread/snubber body with female pipe thread/male pipe thread to hose nipple).... Just looking for something to make a 1 inch or so long snubber with about a .020 or so hole down its length.  Was looking at some copper/brass/aluminum and even ceramic pipe of that small of id, but no go so far.  Want about a .020 id and 3/16 od.....

[Bagger John - #3785]

Mine's very similar to this one:

https://www.universalpowerconversion.com/miniature-inline-orifice-restrictor-p-7416.html

Dorman brand, I believe.

[98valk]

a line restrictor does not work like a snubber does, to different items. a snubber uses a porous disk, metal mesh or a piston.

https://www.directmaterial.com/what-is-a-pressure-snubber

[Bagger John - #3785]

a line restrictor does not work like a snubber does, to different items. a snubber uses a porous disk, metal mesh or a piston.

https://www.directmaterial.com/what-is-a-pressure-snubber

This setup actually works quite well in limiting the amount of instantaneous - not "total" - vacuum which can be pulled. Before putting it on the bike, the restrictor was tested with a hand vacuum pump and verified to lessen the rate of application.

On-the-road testing was done up a certain set of very long, fairly steep hills - think several miles in total, all uphill. If there was going to be a fuel starvation issue due to diminished petcock flow it would be on this stretch of road but the bike actually maintained a steady rate of acceleration throughout.

[Rio Wil]

Both a restrictor or snubber serve to accomplish moderating the vac/pressure pulse applied to the device you are trying to protect. To that end, the one I like is :

Inline Orifice Restrictor, .020 Orifice, 1/8 ID Hose Barb X 1/8 ID Hose Barb, Blue Polysulfone Body
F-2815-201 B85 Specifications
Type:   Inline Orifice
Port 1:   1/8 ID Barb
Port 2:   1/8 ID Barb
Orifice:   0.020"
Manufacturer:   Air Logic

They come 5 in a box for $8.10 plus a $5 low order fee and $17.68 ups shipping ((( :crazy2:for a total of $30.78........

Company is: Universal Power Conversion
 

5636 West 125th Street | Savage, Minnesota 55378

[Rio Wil]

Bagger John.....how/where did you get yours from??

[98valk]

the reason I went with a snubber is because it protects much better than a restrictor for the extreme pulsation that happens when shifting gears esp when pulling higher rpms during a shift.
Vacuum can go from high to low in a split second when shifting, an extreme pulsation event.
The normal pulsation in the vacuum line from the engine running at pretty much steady hwy rpms isn't a high wear stress extreme pulsation condition of the diaphragm whereas a restrictor would be fine if that is all the diaphragm would experience.

I based all of this and why I installed a snubber almost 20 yrs ago from my engineering design experience of Naval ship board low pressure compressed air systems.

IMO a snubber is what is needed to increase the life of the petcock diaphragm. My setup is still working after 50+k miles.  YMMV

[Bagger John - #3785]

Bagger John.....how/where did you get yours from??

AutoZone.

It was a Dorman part. Next time I'm shopping there I'll snap a pic and post it.

[Bagger John - #3785]

My setup is still working after 50+k miles.  YMMV

You realize that vacuum pulsations aren't the only variable in play here, correct?

[98valk]

My setup is still working after 50+k miles.  YMMV

You realize that vacuum pulsations aren't the only variable in play here, correct?

tell me

[Bagger John - #3785]

My setup is still working after 50+k miles.  YMMV

You realize that vacuum pulsations aren't the only variable in play here, correct?

tell me

Atmosphere, average temperature, operating temperature peak and duration as a function of accrued time, volatiles present in the line which can precipitate on and attack the rubber diaphragm. And that doesn't touch on the quality of the part to begin with.

Save the fuel lines, I'm still running the original hoses, tubing and lines on both of my Valkyries. Numerous folks I know of from different parts of the country have had to replace rubber parts on their various bikes (not just the GL1500 models, either) due to dry rot, mold, splitting, environmental contamination. You may find yourself living in a sweet spot where these factors are concerned. If so, consider yourself lucky.

I can also say that before I put a "restrictor" (not "snubber") in the line, the diaphragms on this particular bike would fail roughly every 2 years. Afterwards...so far so good. Makes one wonder why Honda didn't fit a vacuum reservoir, though...and power everything from it like most automotive designs do.

[Rio Wil]

I finally decided on this restrictor available from Amazon for 7 bucks.....be here in a few days, I hope...covid ya know and I am sure its from China.

Dorman 47311 Restrictor 3/16""X.0185

Thinking about it, the stock petcock has not been all that unreliable. My first one died at 80K, rebuilt it and it lasted 100K, then installed a used one from ebay that had bought as an emergency spare  and it lasted 100K, the replacement for it is a Japanese version of the oem (cost $56) and has now about 10K .........so I figure that any help from a restrictor this one should be the "last one I ever buy"....HEHEHE

[hubcapsc]

When I first got my Valkyrie I read all these posts about
petcocks and pingels and extra filters and automatic
shut-off valves and was sure I'd be having to do
all that.

I also read all the shoptalk articles and went to the
Daniel Meyer tech sessions at InZane.

My petcock worked (tested through use and also using
the shoptalk test) when I got my bike and it still works.
I know I rebuilt it in 2019. And somewhere around 2007
or 2008. I'm glad I never changed anything from OEM...

-Mike "ymmv..."

[GWS]

The videos convinced me. That's a remarkable difference. Best part is the fix is right up my alley, no thinking involved - cut line, insert part.

[98valk]

My setup is still working after 50+k miles.  YMMV

You realize that vacuum pulsations aren't the only variable in play here, correct?

tell me

Atmosphere, average temperature, operating temperature peak and duration as a function of accrued time, volatiles present in the line which can precipitate on and attack the rubber diaphragm. And that doesn't touch on the quality of the part to begin with.

Save the fuel lines, I'm still running the original hoses, tubing and lines on both of my Valkyries. Numerous folks I know of from different parts of the country have had to replace rubber parts on their various bikes (not just the GL1500 models, either) due to dry rot, mold, splitting, environmental contamination. You may find yourself living in a sweet spot where these factors are concerned. If so, consider yourself lucky.

I can also say that before I put a "restrictor" (not "snubber") in the line, the diaphragms on this particular bike would fail roughly every 2 years. Afterwards...so far so good. Makes one wonder why Honda didn't fit a vacuum reservoir, though...and power everything from it like most automotive designs do.

all fuel rubber parts on the Valkyrie are made from Nitrile aka Buna-N.  nothing in the fuel system affects it.  only sunlight and temps 250F and over affect it. wear and tear from heavy on/off vacuum such as from shifting wear its out, the manifold vacuum caps are also affected.

[Bagger John - #3785]

My petcock worked (tested through use and also using
the shoptalk test) when I got my bike and it still works.
I know I rebuilt it in 2019. And somewhere around 2007
or 2008. I'm glad I never changed anything from OEM...

That's two rebuilds.

I had a moderate failure of my '99's original diaphragm in 2015 (was able to limp it for the rest of my commute) and a complete failure in 2017 - with less than 5k miles accrued on that diaphragm. The bike had to be flat bedded home.

Since then (and the second rebuild) I put a snubber in the line. I also have a Valkyrie-specific spares pouch which has a cover plate with a blocked-off vacuum port and set of O rings to seal it. I can convert to a manually operated petcock on the side of the road if needed.

Mind you, I do not power-shift either of my Valkyries. They tend to "snick" (not clunk) into gear when shifted around 2000RPM from 1-2 and 2300-2500RPM for the rest of the gears. Thus, there shouldn't be huge vacuum fluctuations.

[Rio Wil]

The videos convinced me. That's a remarkable difference. Best part is the fix is right up my alley, no thinking involved - cut line, insert part.

Those video's were with a .027 restrictor installed and the one I ordered is a .0185.....I will do another video when I get it......if I remember right, it only takes 1-2" of vacuum to keep the fuel port open.......otherwise going up a long steep highway with heavy throttle would starve the engine of fuel.

[Rio Wil]

I hate ordering $hit!!!!!!!! My restrictor came today and the orifice is supposed to be .0185.....and it is .035, plus the blister pak had been opened, mutilated and taped back together.....ARG!

[Bagger John - #3785]

I hate ordering $hit!!!!!!!! My restrictor came today and the orifice is supposed to be .0185.....and it is .035, plus the blister pak had been opened, mutilated and taped back together.....ARG!

I'd be filing a claim with the vendor. Curious why that one got through, but given the quality of staff these days nothing surprises me.

[Rio Wil]

I bought it from amazon....die a return because the wrong part was shipped and amazon said they will refund my money and to not bother to ship the part back.... So, yippee, I have a part I cant use.  So went to  autozone and and they have the same part....035 size orfice...think I will just go get some jb weld and find something about .020 in diameter and see if I cant make the right size orifice.  Glad I am retired..

[Bagger John - #3785]

I bought it from amazon....die a return because the wrong part was shipped and amazon said they will refund my money and to not bother to ship the part back.... So, yippee, I have a part I cant use.  So went to  autozone and and they have the same part....035 size orfice...think I will just go get some jb weld and find something about .020 in diameter and see if I cant make the right size orifice.  Glad I am retired..

Get a Dremel, a small number drill (80 through 83 or so), a piece of brass rod that'll fit snugly into a 3/16" or 1/4" double-male barbed fitting and make your own.

[Rio Wil]

Well.....finally decided to follow Bagger Johns advice and make my own. Piece of 3/16 brass rod, a .108 drill to drill in from both sides and leave about a 1/8 inch section to drill through with .0185 (#75) drill bit. Buy at least two of those little buggars....   Length of the brass piece is about 1.4 inch.

Hope to get some time to soon to do another vacuum video before and after.



Here is a pic of the .0185 drill and the smallest needle from my wifes sewing box....

[Rio Wil]

Here is the final restrictor installed with a .018 orifice....a bit smoother than the .027 orifice.....



https://imgur.com/a/arPO2q0