Petcock – what part is failing?

[1500Rider]

In my ongoing Valkyrie rebuild, I pulled the petcock and rebuilt the cover set, replacing the diaphragms and spring. Good thing I did as the previous owner had obviously done the same thing in the past and put it together incorrectly!

I tested the part and it seems to be working perfectly (will find out when the bike is back together). After studying the part and noting how simple it is I was wondering what part in the petcock is causing all the problems owners seem to be having? I noted that the larger diaphragm had what looked like tattered edges. Is this the part that usually fails? Wasn't sure if it was the petcock itself that fails or the cover set. Any insights?

[Blackduck]

The only problem I have had was the very small vent hole in the check valve blocked and this does not allow the  vacuum to release. The petcock stays on when this happens.
Cheers Steve

[Thunderbolt]

mine wore a small hole near the center of the diapragm and the vacuum was too low to allow enough fuel to flow.  It kept acting as if it was about to run out of fuel.  Continued movement rubbed the hole near the small aluminum piece that ties the diapragm's together.  It was pulling air in from the weep hole.  Found out that if I had covered the weep hole it would have worked better to get me home.

[RP#62]

Just repaired the one on my wife's bike.  It had a small hole in the little diaphragm and was pissing out the weep hole when the valve was in the ON position. Sandy was kind enough to give me his spare.  Thanks again Sandy.
-RP

[98valk]

my oem diaphragm worn out in the center after 13k miles.  after rebuilding and installing a snubber in the vacuum line, now with 21k and no problems.

http://www.valkyrieforum.com/bbs/index.php/topic,7231.msg54893.html#msg54893

http://www.valkyrieforum.com/bbs/index.php/topic,10058.0.html

[1500Rider]

From the responses so far the diaphragm seems to be a major problem, however, if the diaphragm fails, wouldn't this cause a loss in vacuum and restrict fuel flow? What part is failing that is causing all the hydrolock problems even with the petcock in the off position? Something internal to the petcock itself and not in the cover set?

I've never had a petcock problem with any of the other bikes I've owed (own) and am curious exactly what is making the Valkyrie unit so prone to problems.

[98valk]

From the responses so far the diaphragm seems to be a major problem, however, if the diaphragm fails, wouldn't this cause a loss in vacuum and restrict fuel flow? What part is failing that is causing all the hydrolock problems even with the petcock in the off position? Something internal to the petcock itself and not in the cover set?

I've never had a petcock problem with any of the other bikes I've owed (own) and am curious exactly what is making the Valkyrie unit so prone to problems.

see my posts on the hydro problem,

http://www.valkyrieforum.com/bbs/index.php/topic,22852.0.html

[Ricky-D]

If a problem happens with the petcock while the bike is parked, the most likely cause will be the "off", "on", and "res" function of the petcock. It is a separate side of the petcock and to me, is totally unreliable.

***

[98valk]

If a problem happens with the petcock while the bike is parked, the most likely cause will be the "off", "on", and "res" function of the petcock. It is a separate side of the petcock and to me, is totally unreliable.

***

it shouldn't matter if the petcock is leaking by or not. the needle and seat of the floats will stop any flow, if they don't then those cylinders will be overly rich or flooding out while running.
from an engineering standpoint I believe its the vent tubes similar to the goldwing problem.

[Hoser]

If your'e old school and always turn off and on your fuel manually, a manual petcock will solve everything.  If not, rebuild it annually.  Hoser

[Chrisj CMA]

In my opinion the failure is anyone who tries to fix/keep one of these things.  Once they start acting up (even before actually) the only smart thing is to get rid of it......the failure is keeping it at all.  There are so much better valves out there, and Honda sure messed up with this thing........

[1500Rider]

Thanks for the information everyone. Seems like no matter what you do to the cover set the petcock is ultimately the problem. Strange that sometime so simple should be the source of so many problems. While I haven't had a problems yet, looks like I'm going to look into a Pingel sooner rather than later.

On a side note, I was looking at getting some engine hangers to dress up the side. Does anybody make some that will work with the Pingel?

[valkyriemc]

"There are so much better valves out there, and Honda sure messed up with this thing........"




Yup, here's one;

[valkyriemc]

Here's another,  the vacuum model that I used, with extended pickup and external filter ;

[Mildew]

My diaphragm looked normal but when stretched you could see daylight through it. I just cut the center out and jb welded the weep holes. I used the fuel line to the cylinder as a dummy line and jb welded the weep holes. It's been working great this way for years. I'll probably take it apart this weekend to see if the jb weld has been holding up.
 http://daughertymotorsports.com/howto/Tankvalve/tankvalve.html