Jump to content

Rebuilt vacuum petcock, but...


johnsnownw
This post is 5248 days old and we'd rather you create a new post instead of adding to this one. You can't reply in this post.

Recommended Posts

Right, so I rebuilt the petcock and have just installed it back in the tank. However, before putting it back on the bike I wanted to make sure that there were not leaks. Well, after putting gas in the tank fuel will leak out of the petcock no matter the position of the lever, i.e. Res, ON, Prime. Seems to leak more on Prime though. I guess I need to know if there is anything wrong, or whether it will do this until I hook up the vacuum bit for the first time?

Thanks.

Link to comment
Share on other sites

Do you want an ad-free experience? Join today and help support the Yamaha Owners Club.

Summick not right there Johnno :mellow: , it should pour out on PRIme, but not the other two positions, the prime allows petrol to flow to the carbs without the presence of vacuum, ON and REServe need vacuum, you need to take it back off the tank and check the diaphragm in the pet-cock

Link to comment
Share on other sites

Summick not right there Johnno :mellow: , it should pour out on PRIme, but not the other two positions, the prime allows petrol to flow to the carbs without the presence of vacuum, ON and REServe need vacuum, you need to take it back off the tank and check the diaphragm in the pet-cock

Well, just took it apart and put it back together. There is a little notch/channel in the rubber/plastic piece that fits between the two diaphragms. Is there a place where the notch should be in particular? i.e. facing the top or bottom when the petcock is in the tank.

Link to comment
Share on other sites

Absolutely no idea m8, I dont have your model of bike, but it shouldn't be pissing petrol as you describe :mellow:

Link to comment
Share on other sites

P.S. if this is on the XS then Drewpy's your man ! ;)

Link to comment
Share on other sites

P.S. if this is on the XS then Drewpy's your man ! ;)

Oh it's the XS alright. Well I tried again and it still leaks. No idea what the problem could be.

Link to comment
Share on other sites

  • Moderator

MMM, last time I rebuilt the petcock it leaked. <_<

Can't remember what I did to fix it though, I got an old one in me bitz box somewhere, give me till tomorrow and i'll dismantle it and check for you

Drewps

Link to comment
Share on other sites

MMM, last time I rebuilt the petcock it leaked. <_<

Can't remember what I did to fix it though, I got an old one in me bitz box somewhere, give me till tomorrow and i'll dismantle it and check for you

Drewps

Thanks drewps, so far I've dismantled the thing 3 times. Hasn't made a bit of difference. I keep thinking it has something to do with the notch in the plastic bit. It's located in one of the corners on the side that doesn't hold the metal circular plate.

Link to comment
Share on other sites

  • Moderator

This would be the notch/channel I've mentioned:

img1491ts.jpg

right had a looksey;

the diaphram has two layers between which the plastic sandwich plate is positioned.

the groove/notch is some sort of pressure release thng to stop air being trapped and preventing the full travel

the O ring at the tip of the piston seals the gas in.

the notch is where the vacuum spigot is which is facing up when mounted on the tank

hope that helps

Link to comment
Share on other sites

right had a looksey;

the diaphram has two layers between which the plastic sandwich plate is positioned.

the groove/notch is some sort of pressure release thng to stop air being trapped and preventing the full travel

the O ring at the tip of the piston seals the gas in.

the notch is where the vacuum spigot is which is facing up when mounted on the tank

hope that helps

Thanks Drewps. Would you happen to know if it makes a difference that one of the cut out holes in the diaphragm is directly over the channel.

Link to comment
Share on other sites

  • Moderator

Thanks Drewps. Would you happen to know if it makes a difference that one of the cut out holes in the diaphragm is directly over the channel.

it was on the one i looked at, the casting blocks it off anyways

Link to comment
Share on other sites

it was on the one i looked at, the casting blocks it off anyways

Well, I decided to stretch out the spring a bit, so that it puts more pressure on the nipple. Now, instead of leaking fuel like a sieve it only drips. Now, since I already have an inline shut off valve, I think that's acceptable. Or should I just say screw it a purchase a manual petcock?

Link to comment
Share on other sites

×
×
  • Create New...