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Author Topic: A new idea for hydrolock prevention.  (Read 1210 times)
rekit
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Posts: 61


Let's Go!

77532


« on: January 13, 2014, 06:46:36 PM »

Reading a lot of petcock threads it occurred to me that there may be a much simpler solution, as far as fuel to #6 intake goes. How about just lengthen that tube that goes from the petcock to #6 and put a loop above the gas level (if there's room up by the front of the tank?), or a valve in that line. Some clear tubing so you would have a visual indication of fuel in the line. Now it would still suck gas into the line when it was running if there was a petcock failure, but while parked the loop should prevent gravity flow to #6 intake, as long as your tank vent was ok.
  A quality valve on that vacuum hose would also help while parked, and you would know right away to turn it on (G), might help train you to turn it off. An electric valve would be great as well and being smaller, shouldn't be too expensive.
  I haven't tried it yet on my Interstate, and I have a Dan-Marc on the way, but will look into it. So, any thoughts?
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Bought a brand new Z1 in 74 and sold it later to get a "family car" DOH!! My brother had a Kaw H1 at the time as well. Oh well, good times! Lately Mean Streak, CBX, Nighthawk 750, Connie, KZ1000, Yamaha TTR 250, KTM 250
snakemeister
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Posts: 90

Alabama


« Reply #1 on: January 13, 2014, 09:09:54 PM »

  For the loop in the fuel line to work the top of the loop would have to be above the top of the fuel tank. Any one way valve in the fuel line would probably have to be electrically operated as any valve strong enough to hold back the pressure of a full tank of gas might not open with just engine vacuum.
  I just replaced the stock original petcock on my '97 Tourer with a stock petcock just for peace of mind and I'm not going to worry about hydrolock anymore.
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Chrisj CMA
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Crestview (Panhandle) Florida


« Reply #2 on: January 14, 2014, 05:08:10 AM »

Ive never had, nor seen a hydrolocked Valkyrie...however I think you are assuming that fuel entering the vacuum line to #6 is the primary cause.  I dont think that is the case.  My understanding is fuel flows into the cylinder from whichever carburator has a stuck needle valve and fuel enters the carb from the normal fuel supply , not a vacuum line.
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jmann
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Mesa,Az.


« Reply #3 on: January 14, 2014, 07:43:32 AM »

I can certainly appreciate wanting to prevent the hydrolock condition but it seems as though you are wanting to reinvent the wheel. The dan marc appears to be the BEST solution if concerned and if not then get in the habit of each time you start your bike only tap the start button to see if she turns. If she does then GTG if a clunk then pull the plugs.   cooldude
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Valkpilot
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What does the data say?

Corinth, Texas


« Reply #4 on: January 14, 2014, 09:23:33 AM »

Ive never had, nor seen a hydrolocked Valkyrie...however I think you are assuming that fuel entering the vacuum line to #6 is the primary cause.  I dont think that is the case.  My understanding is fuel flows into the cylinder from whichever carburator has a stuck needle valve and fuel enters the carb from the normal fuel supply , not a vacuum line.

I agree.

For fuel to get to the vacuum line connecting the petcock to the #6 carb, the manual shut off either has to have been left open or the ball & detent system has to have failed, the diaphragm that seals the flow from the outlet to the fuel line has to have failed (or the spring that holds it shut needs to have slipped), the fuel line has to have filled to the point of backup, the weep/pressure relief hole has to be clogged, and there has to be a hole in the vacuum diaphragm.

Not an impossible combination, but not a probable one either.

Leaving the petcock in an "on" position, with a coincidental failure of the spring that holds the sealing diaphragm closed is the more likely path to hydrolock. (To the best of my knowledge, no one has ever discussed a hole in the sealing diaphram.)  And, as Chris points out, some failure of the floats and/or fuel filling the carb rail vent lines must happen as well.

Two separate polls of this forum done a year or so apart both indicated that over 86% of the respondents had never had a problem with fuel in their cylinders.  And, such polls tend to be biased toward negative responses from those who have had an issue, so I'm inclined to believe that actual incident rate is much lower than the 14% indicated by the polls.

Petcock failure resulting in hydrolock is much discussed and feared, which leads to the impression that it is a very frequent occurrence.  It's not.

The more likely way the petcock will let you down is wear on the vacuum diagphragm, which eventually results in restriction in fuel flow to the point that the bike quits running.  If there is a compelling reason to go to a manual petcock/Dan-Marc solenoid shutoff setup, this is it.
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