Ticking fuel petcock

[Dave T.]

When I bought my V, it had an annoying ticking sound coming from the vacuum valve, so I disconnected it. Now I have fuel going all over when I remove the tank. Is there still parts available for this? Like the diaphram and spring?

 ???

[Silver_Bullet]

Dave,
I assume you are talking about the petcock?  I've rebuilt mine, go to the links and look for BikeBandit.  I puchased a rebuild kit from them and it worked.  Hope this helps.

Mark

[Silver_Bullet]

I just saw a petcock repair kit for sale on ebay.  Look under motorcycle parts and assessories, type in "Yamaha Vision" and check "In title and descriptions"

Mark

[Dave T.]

I will check it out. I just need the spring I think. Diaphram is still in it.

Thks man...  8)

[Dave T.]

I got a spring and an o-ring for my petcock vacuum valve. I hooked up the shut off valve again and IT STILL TICKS! ?>:(

Don't tell me no one out there has ever had this problem. At low RPM's it's like it's tapping the tank with a nail and it drives me nuts! Usually it happens from 1500-3000 rpm's. I think it's caused by the metal piece on the spring side of the diaphram hitting the petcock body when it pulses at low rpm's. Am I just going to have to deal with it? ?Any ideas out there? ???

[ofstone]

hi dave,

it sounds to me that the small valve the petcock vacuum line for the petcock.

if you carefully remove the brass nipple from the petcock where you connect the vacuum line, a small round pertinax circle fals out. Watch out with it, because it breakes easy.
if that one is missing or damaged, your valve will be opening and closing every time the piston is sucking air and fuel from the carb. The valve is there so the vacuum can quikly open the petcock valve, but slowly close the valve. (via a small air bypass visible when the petcock is opened.) it creates some kind of delay closing. with the valve and engine running idle, the fuel valve will never completely close.
I had the same problem, when i accidentally broke the pertinax circle in 2 during petcock rebuild. I made a new one fron a 0.6 mm thin pertinax board (the one used in electronics) and cut it out.

[Lucky]

See now, my fist thought was that the ticking sound was the built in "self destruct" clock in the stator, lol

not to make light of your problem, but it's late at night, and I couldn't resist...

[Dave T.]

hi dave,

it sounds to me that the small valve the petcock vacuum line for the petcock.

if you carefully remove the brass nipple from the petcock where you connect the vacuum line, a small round pertinax circle fals out. Watch out with it, because it breakes easy.
if that one is missing or damaged, your valve will be opening and closing every time the piston is sucking air and fuel from the carb. The valve is there so the vacuum can quikly open the petcock valve, but slowly close the valve. (via a small air bypass visible when the petcock is opened.) it creates some kind of delay closing. with the valve and engine running idle, the fuel valve will never completely close.
I had the same problem, when i accidentally broke the pertinax circle in 2 during petcock rebuild. I made a new one fron a 0.6 mm thin pertinax board (the one used in electronics) and cut it out.

There is a check valve in the brass fitting. I will check it out. Thanks!

BTW, WTF does pertinax mean??