Electric Fuel Shutoff

Rationale

This one is really important. The purpose is to ensure against hydro-lock.  What is "hydro-lock"?
That's what happens if fuel leaks down into a cylinder while the bike is parked, and you go to start it.  The piston in the filled cylinder tries to compress the air-fuel mixture, but instead it slams into the incompressible fuel.  On the Valkyrie, the starter motor is so strong that it destroys the starter and/or ring gears.  With NO warning, you're walkin and about to shell out a couple thou to fix it.  You have to pull the engine and that gets spendy.

"Oh, but no problemo, that's what the vacuum petcock is for, even if I forget to turn it off..."

Nice try.  That $150 petcock is a P.O.S.  It leaks.  I've replaced mine once under warranty, and rebuilt it several times.  All it needs is a little sand in it, and you have a leak.  It WILL get sand in it - there's no fuel filter, just an inadequate screen tube, and fuel from the pump is notoriously unclean. Have you ever been surprised that you didn't hit reserve yet -  you usually hit it 20 miles ago?  Oh, OK, there it's stumbling, guess I just got some great mileage.  Hey wait a minute - I turned the petcock, how come it's still stumbling?  Oops.  Because you've already used up your reserve, thanks to that leaking P.O.S. 

OK, so now the petcock leaks, doesn't shutoff either manually or by vacuum - now you're depending on ALL SIX carburetor float valves to not leak.  But the sand is already getting through the screen tube and the petcock, guess where it goes next?  All you need is ONE grain of sand to block ONE float needle valve open, and for the engine to stop - one chance in four - with the intake valve for that cylinder open.  (That's a duration of approx 180° out of 720° of the 4-cycle engine's possible states.)  Sounds a bit like Russian Roulette, only with worse odds, but not quite so bad results.

There are other ways to address this concern.  Some folks replace the petcock with a Pingle.  Not a bad idea - though it's more spendy, and they don't have one that hooks up to the knob so you have to reach under there.  Around $120 or so, if I recall.  Another fix, is to install a fuel filter to keep the sand out.  Well, that's a good idea - but not great.  Only helps if the leakage is caused only by crud in the gas.  Could happen for other reasons too, like worn parts, or failing gaskets.  Some folks do two, even all of these anti-leaking solutions. 

Installing a Dan-Marc electric shutoff valve gets the most bang for the buck.  The valve is about $29 online including shipping.  Fuel line and fittings, $10 at most.  And you have a system that will pass gas only when the ignition is on - and there is a vacuum (engine is running) - and the petcock is turned on.  Unless the petcock has failed.  Then the ignition shut-off is your fail-safe backup. Bonus - you can install a switch in a hidden location, say on the handlebar under a lever, and you have an anti-hijack/theft device.

Cost

$29 for the Dan-Marc.   $10 or so for fuel line & fittings.

Time

An afternoon.  Half the time is spent pulling the tank and the airbox.

Materials
 

• Dan-Marc Valve from http://www.dan-marc.com/79-afc11112.html Just google if the link breaks.
• a couple feet of 3/8" (I think) fuel line.  Take your fuel line with you to match it up.
• I replaced those spring hose clamps with 8 screw hose clamps
• Inline fuse holder
• toggle switch (optional)
• several feet of multistrand 18ga wire (optional)
• wire ties

Tools I used
 

• Screwdriver
• hose cutter
• soldering equipment including shrink tube
• Long needlenose pliers
• 1/4" drive metric socket set

Process

Drain the tank using a siphon hose.  Remove the tank and airbox.  Remember to unscrew the knob, there's a phillips screw inside the knob hole.  You also have to pull off the main fuel line and the vacuum line (other side).  Front and back screw (10mm & 12mm hex heads) and it comes off.

Check the picture above.  I added fuel line to the left and right sides of the T fitting so I could move the fuel line T fitting forward to allow the Dan-Marc to sit ahead of the crossmember.  This is to make it easier to reconnect the fuel line at the petcock - provides some flex movement.  Found this out the hard way. Don't worry about those glass tubes below in the pic - it's neon for my night lights, which I decided wasn't such a good idea - potential sparks from high voltage in this location, maybe not so good.

Connect the two wires on the Dan-Marc:  one of them to a ground - solder on a ring connector and secure it with a screw to ground.  The other wire - connect to the accessory circuit (Lg/R), or to the running lights circuit Bl/Br).  It doesn't matter which is hot & which is ground. Put an on/off toggle switch in this line (or the ground line) and hide it, if you want to have a hidden fuel shutoff.  Or install a relay as a "latch" - so if you kill the engine by the kill switch, the fuel shuts off and won't turn back on unless a hidden switch is cycled, or (using relays) a sequence of operator switches is used - e.g. left turn first, then right with brake light.

This is also a good time to desmog if you haven't done that already.  While you have the air box off.  I did it now, anyway.  Here's a link to some good instructions: http://www.valkyrieriders.com/shoptalk/desmog.htm

Use

It's automatic.  Enables fuel flow when the ignition is on.  Now you can stop worrying about hydrolock.