Convert petcock to simple gravity feed?

[SuperCell]

With all the petcock issues on these bikes, why not try this:

Remove the 4 screws securing the "vacuum plate" to the petcock body. Throw the plate and diaphragm in the garbage. Make a small block-off plate out of heavy-gauge sheet metal to replace the old vacuum plate. Install this plate with a new gasket. Now, you have a simple, reliable, gravity-feed petcock. Simply install a fuel shutoff valve in the main feed line, and switch it to "off" when you're not riding.

What do you think?

[ptm]

The reason bikes have vacuum controlled fuel flow is so that the fuel is flowing only when the engine is running (and creating a vacuum) which is useful in two scenarios - 1) you can easily take the tank off the bike for maintenance or whatever without any fuel leaking, and 2) if you ever have an accident, it reduces the possibility of fuel leaking all over the place and making a major fire/explosion risk.

Most petcocks have a Prime position which works like the setup you're recommending - it's a straight shot to the carbs (just add the shutoff valve). But it's only intended to be used to fill the bowls with fuel after it's been sitting for a while or after a rebuild.

I've got the stock petcocks on all three bikes and, like most things, once their sorted out, they work fine.

That's my $.02

[koolaid_kid]

I have to agree with ptm. I have liked the concept since my 1966 X-5 Invader; it is not only safer, but easier to work on and you do not have to remember to shut the blasted thing off every time you stop.

[Cyg]

Actually on some of the bikes I had in the past and ended up selling too get a better bike. I did just that when the vaccum part failed. I would just install a shut off valve in between the tank and the carbs. As for dismantenly a fine working one. I haven't done that yet. But for some who find problems with thier petcocks. Yes its an easy fix.

[Footy.]

With all the petcock issues on these bikes, why not try this:

Remove the 4 screws securing the "vacuum plate" to the petcock body. Throw the plate and diaphragm in the garbage. Make a small block-off plate out of heavy-gauge sheet metal to replace the old vacuum plate. Install this plate with a new gasket. Now, you have a simple, reliable, gravity-feed petcock. Simply install a fuel shutoff valve in the main feed line, and switch it to "off" when you're not riding.

What do you think?

This is what i did on my 78 GS750E.

To do it properly, you need to blank of a port in the petcock that feeds the prime position. Then prime becomes "off".

On and reserve stay the same.

Footy.

[Billy Ricks]

Somewhere in the archives is a post about converting the stock petcock to gravity fed and having an off position. It involved cutting the stop off the petcock for the lever so it can be turned straight up to block fuel flow.

[feelergaugephil]

With all the petcock issues on these bikes, why not try this:

petcock. Simply install a fuel shutoff valve in the main feed line, and switch it to "off" when you're not riding.

What do you think?

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