Question about Petcock rebuild kits

85 XJ700 N--I bought the rebuild kit from Chacal. Cleaned and polished the petcock according the Fitz's instructions and put everything back together. It doesn't work, and I have been able to determine that the plunger is not reaching the seat of petcock. I am wondering if I received the wrong plunger. Does anyone know if the plungers for the two kits are different? I've checked and rechecked the instructions, pictures, and posts, and either I'm absolutely stupid or this plunger is simply too short.

 

Re: Question abut Petcock rebuild kits

As long as you didn't get the plastic diaphragm spacer plate installed "flipped over"--- You may need to "adjust" the profile of the metal plate on the other side of diaphragm, away from the plunger.

If it's not flat, or the plunger isn't sitting at exactly 90 degrees to it, it will prevent the plunger from seating correctly. The problem occurs more often on the "large body" petcocks, because the aforementioned plate is of a much larger diameter.

If it needs adjusting, a couple of appropriately sized sockets and some gentle tappage is all that's required.

I've encountered the problem myself to varying degrees with large-body petcocks; I'm going to be adding some additional pics and text to the how-to.

 

Re: Question abut Petcock rebuild kits

the plastic plate is as shown in your pictures, with the vent on the plunger side and pointed down and to the rear.

When you mention the metal plate I assume you mean the quarter size metal plate that is part of the diaphragm/plunger, and is on the vacuum side of the plastic piece. It appears to be flat and in place with the plunger at a 90 degree position, but I'm just eye-balling that. I had considered trying to tap the vacuum side to see if I could lengthen the plunger but decided that wasn't a good idea.

If that is the piece your are talking about adjusting, I don't understand what you mean by two sockets and some gentle taping. Can you explain how to position the sockets, and a picture would be great.

By the way, I substituted my original diaphragm which was working when I removed it, and now it doesn't work either. I replaced it because the o-ring was showing signs of wear. All I really needed was the rubber piece on the lever side because it was torn a little and allowing the petcock to leak slightly. Should have left well enough alone.

Thanks for your help. Got my carbs spotless and ready to get it all back together and see how it works.

 

Re: Question abut Petcock rebuild kits

A CLUE!

Define "doesn't work." Won't flow; or won't shut off?

Adjusting/straightening the metal plate involves using a large socket that just "fits" the outer flange as your anvil, and then using a much smaller socket that just fits over the rivet head that is the backside of the plunger as your swedge.

But I suspect that if the old one has now suddenly ceased working altogether there might be something else afoot.

When you said you polished it-- did you polish the valve seat itself? Did it have any pitting or "rings" worn into it?

Are you using the stock spring or the aftermarket spring? "Booster" washer?

Don't start hammering the metal disc just yet. You need to compare the old and new diaphragm assemblies carefully, for the height of the plunger tip-to-disc, and plunger alignment, etc., before doing any tweaking there.

 

Re: Question abut Petcock rebuild kits

I'm going to try and post pictures. The new diaphragm is the one installed on the plastic plate.

it will not shut off. Pours gas in reserve and on almost as fast as in primary

I polished the seat only--with a cotton attachment on my dremel. There was not pitting at all, no grooves, nothing. I polished it just because I had it apart and you said to in your instructions. Didn't use anything other than a little carb cleaner, so all I did was just shine it up.

I'm using the original spring, but with the added washer. With the vacuum portion off, I can press on the plunger and it still doesn't seal. That's how I determined that the plunger doesn't seem to bet seating.

 

Re: Question abut Petcock rebuild kits

I had exactly the same problem with my old XJ700X.
All the after market rebuild kits would result in the same issue.

But there is a kit from Kawasaki that will work:

Kawasaki Part#: 43028-1015

 

Re: Question abut Petcock rebuild kits

Success at last. Based on what Fitz and Chacal suggested, I put the diaphragm in a long socket, plunger down, (about 1/2 inch, but 3/8 would probably better) and gently tapped the vacuum side of the plunger with a hammer to create a small dimple and effectively making the plunger a little longer. It seats well and works like a champ. If you try it, remember just a very light tap--the metal disk is very thin and bends easily. Initially I tried to stuff the rubber flaps into the socket but decided against that and no damage was done to the flaps.