Vaccum petcock convert without replacing?

[Anonymous]

I now know!!! Thanks!!!

[kinch]

If you open it up and take the diaphragm and spring stuff out, you can easily convert it like I did.

Take out the selector barrel and figure out which of the two holes is used for "prime".

Fill that hole with JBWeld. Be careful to only fill that hole, and don't get any on the exterior of the barrel. Let dry overnight.

Put the barrel back in.

Use Form-a-gasket or something similar when you put the rear cap (vacuum cap) back on. This area will be flooded with gas after the mod.

Cap the vacuum line nipple with something fuel resistant. You could also stuff it full of JBWeld for a permanant solution.


Doing this mod will let you use the stock petcock as a manual system while still retaining the reserve function. Turning the switch to "prime" now shuts off the fuel. I have been using it this way for 3 years now with no problems.

Good luck....

This is an old post that came up in a search. I've been having all kinds of problems with the vaccum system on my 1980 GS850L. I saw this post and it seems like a great solution but I opened up my petcock and I can't tell which parts are referenced in this fix and I'm wondering if I just have a different petcock? Here's mine:

[SqDancerLynn1]

1980 you may have the petcock with the screwdriver slot!! If so REPLACE IT

[kinch]

It does which is the bane of my existence. I was having issues with it, replaced it with NOS but started having problems again after while. Also, why they made the screwdriver slot out of plastic with the same density of margarine is beyond me.

I'd drop cash on a pingel (or any other after-market) but I can't find a non-vaccum replacement for that year.

[kinch]

Hmm, looking at the adapter plates on Z1 wondering if they would work....

[kinch]

So I'm thinking this:

http://www.z1enterprises.com/detail.aspx?ID=2718

Plus this: ('kinell, $89!)

http://www.z1enterprises.com/detail.aspx?ID=1743

Or this:

http://www.z1enterprises.com/detail.aspx?ID=1744

If anyone's tried it before please let me know. Off for a ride, I'll check back in a bit.

[don]

I'm not sure what exact problem your valve is causing, but I also had valve problems. My solution was to buy a $4.00 spring loaded vacuum ball check valve and put it in line with the vacuum hose between the carb and the fuel valve. Poof.... like magic...and it was only $4.00 in stead of $90.00. No muss, no fuss.

[don]

Oh. Forgot to mention. All functions of the fuel valve work as they were intended to also. (Pri,Run,Res)

[kinch]

I'll have to admit to a lack of understanding of the vacuum system here. I wouldn't have thought to put a valve in-line with the vacuum hose. I thought about just putting an off/on valve onto the fuel line in between the petcock and carbs and just leaving the petcock on reserve but sometimes it seems like even the reserve closes up from time to time and I have to take the vacuum line off of the carb and siphon to pop the fuel valve open because the engine isn't doing it.

[don]

Ah. Now I understand. You are haveing a problem with lack of fuel. It sounds like the vacuum isn't getting to the fuel diaphram. Putting a check valve in line won't help you then. If your petcock is like mine, there is a "built-in" check valve in the vacuum "cover", ( the part of the petcock assembly that has the vacuum port to put the hose from the carbs onto). In my case, that "built-in" check valve was decintegrated. That made the fuel diaphram act like a fuel pump and pressureized the fuel system. You too may have a problem with this "built-in" valve. I removed mine completely. But if you do that, you WILL have to put a check valve in the vacuum line or it will pump fuel in sted of simply opening the fuel diaphram.

A bit long winded. (sory) But, hope it helps somehow.

Good luck.

[kinch]

Thanks Don. With as much trouble as this thing has given me I just bit the bullet and picked up the pingel adapter plate and the cheap petcock to fit it:

http://www.z1enterprises.com/detail.aspx?ID=1744

Hooked it all up, it fit great and solved the problem...that is until gas started leaking from under the gasket that's provided with the adapter plate

I'm hoping that I just didn't prep it well enough with the sealing compound. Going to clean it all off and try again, we'll see.