84 Venture gas seeping out of petcock

[venturesome]

Will I need to remove the petcock to fix this problem, or can I rebuild "in place"? I noticed that there is an o-ring that I can get to just by removing the plastic knob and two screws holding the plate on. Does anyone know the size of this oring? It appears to be 17mm OD, but I don't know ID. Hopefully replacing this oring will stop the leak, looks like a new petcock is about $75.00!

[Prairiehammer]

I can't help you as to the size of that O-ring, but here is a pic of a disassembled 1983 '26H' petcock. The '41R' (since superseded by the '3JJ') petcock on your 1984 may be similar.

Of course, make sure your fuel tank is empty before disassembling the petcock!

 

The 1984 41R:

 

This MIGHT be the O-ring you require:

http://www.ebay.com/itm/YAMAHA-FUEL-VALVE-PETCOCK-GASKET-LEVER-SEAL-YFP350-YFS200-YFA1-XVZ1300-XVZ12-/360924277737

 

Here is a complete used 1984 petcock:

http://www.ebay.com/itm/1984-Yamaha-Venture-XVZ12-D-fruel-shut-off-fuel-petcock-/201323851491?hash=item2edfd62ee3&vxp=mtr

Edited April 25, 2015 by Prairiehammer

[H2O]

Looking at these pics I see a small in-line filter. Is this in the later model XVZ's too?

[Prairiehammer]

Looking at these pics I see a small in-line filter. Is this in the later model XVZ's too?

 

If by 'small inline filter' you mean the two upright vertical plastic strainers, yes there are two of those strainers on all the First Gen Venture petcocks, except for the 1983, where there is just one strainer, because the 1983 petcock does not have a reserve.

[venturesome]

I drained the tank and disassembled the selector parts. The o-ring appears to be a 14mm ID x 1.5mm. The original o-ring was shrunk and somewhat loose. I ordered new viton o-ring (and some spares) from oringsUSA. Hope this works!!

Is there a lubricant that can be used on the selector that makes it turn easier?

[H2O]

If by 'small inline filter' you mean the two upright vertical plastic strainers, yes there are two of those strainers on all the First Gen Venture petcocks, except for the 1983, where there is just one strainer, because the 1983 petcock does not have a reserve.[/quote

 

Okay. The pic with all the parts laid out shows what appears to be a small orangish filter/strainer near the top of the photo. Does this thing, and the upright strainers become dirty and clogged?

The small orange colored strainer closely resembles what's inside Mikuni carburetors on Seadoo jet skis, and they can become clogged up. Looks like I should've taken this apart during my recent tank draining and fuel pump replacement...?

[Prairiehammer]

Is there a lubricant that can be used on the selector that makes it turn easier?

 

I've contemplated that question myself in the past. The valve consists of a hollow plastic tapered plug. Tapered plug valves are inherently difficult to turn because of the high friction between the tapered plug and the matching tapered cavity in the valve body. Add the accumulated gasoline varnish and detritus of 25 years and the friction is even greater. If the tapered cavity within the potmetal petcock body becomes corroded (likely) then the tapered cone/plug gets even harder to turn.

I would clean the plastic plug/cone and clean the internal cavity, ensuring there is no pitting or abrasive crud. If you decide to use an aggressive abrasive on either, be very careful to not remove any material or change the shape and fit of the tapered cone or cavity.

Finally, a bit of grease (silicone or petroleum) will undoubtedly help relieve some of the friction, but I have my doubts as to longevity of the lubricant in the gasoline environment.

[Prairiehammer]

Okay. The pic with all the parts laid out shows what appears to be a small orangish filter/strainer near the top of the photo. Does this thing, and the upright strainers become dirty and clogged?

 

The small orangish filter/strainer is actually the standpipe. It has been removed from the petcock body in that picture. Yes, sometimes debris from the tank will plug the strainer(s). Unless the debris is adhered gasoline varnish, back flushing will usually clear the screen.

More commonly, the plastic standpipe(s) fall out of the petcock body. Then of course, there is no strainer to plug, but the debris will pass through the open petcock, hopefully to be captured by the main fuel filter. If the taller standpipe does fall out, then there is no reserve capability.

In the Venture carbs there is also a small, stainless steel, fine mesh filter (called the net filter) immediately before the float valve assembly. It is rare to have a plugged net filter.

[H2O]

The small orangish filter/strainer is actually the standpipe. It has been removed from the petcock body in that picture. Yes, sometimes debris from the tank will plug the strainer(s). Unless the debris is adhered gasoline varnish, back flushing will usually clear the screen.

More commonly, the plastic standpipe(s) fall out of the petcock body. Then of course, there is no strainer to plug, but the debris will pass through the open petcock, hopefully to be captured by the main fuel filter. If the taller standpipe does fall out, then there is no reserve capability.

In the Venture carbs there is also a small, stainless steel, fine mesh filter (called the net filter) immediately before the float valve assembly. It is rare to have a plugged net filter.

[ATTACH=CONFIG]98992[/ATTACH]

 

Good to know. Thanks for the info!