Author Topic: How come we don't all install in-line fuel valves to block hydolock?  (Read 22550 times)

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Offline connie_rider

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Re: How come we don't all install in-line fuel valves to block hydolock?
« Reply #250 on: August 08, 2017, 07:14:06 pm »
m in sc, I kinda question your statement?

The reality of the max requirement is  = or > than the flow capacity of ( the main and pilot jets per carb, which will be less than the float needle seat per carb) x4. That's just the way it works on a gravity feed system.

I agree that flow thru the float needle seat per carb is gravity feed. But the Jetts have a vacuum on the back side of the jett.
 I would think that makes that flow thru the main jets, a pressure feed? (approx. 14.7 psi)

MOB: I think the fuel line ID is about 5/16".
         But the size of the fuel line is not the fuel restriction.
         The limiting diameter is inside the petcock, or (if smaller) inside an add-on valve.

Harry sed the port size in the stock petcock is 1/4".
 That surprise's me a little.
I thought the orifice size in the petcock (at the selector valve itself) was smaller than that.
  Guess I'll have to open my spare petcock and check Harry's dimensions..

The point is; These guys have successfully used various valves to stop fuel flow for multiple years..
                    So, we can't say their idea's didn't work.
                      I guess it's possible that they haven't rode long and hard e'nuff for fuel restriction to be a problem?
                      But, I suspect they've thrashed their bike's {at some point} to check things out.

Again; I'm not interested in using a {additional} valve for preventing hydrolock.
          That's already solved with the overflow tubes.
I'm only looking for a way to stop petcock leakage while stored.

I'll add that if you stop petcock leakage, hydrolock is far less likely.

Ride safe, Ted
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03 Connie (Buddy)

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Re: How come we don't all install in-line fuel valves to block hydolock?
« Reply #251 on: August 08, 2017, 07:41:57 pm »
Yeah Ted... that's why I implied, jokingly, about the fuel line size... because its 5/16"..... and kinda throws off the 1/4" barbed fitting theory in my mind.
I just figured "let it flow.." and didn't say anything. :rotflmao: :)

Liquids flowing via gravity, thru a circuit, reduce in flow and increase in pressure when the encounter a reduction in cross section.
The opposite occurs when a smaller diameter turns into a larger diameter, flow increases and pressure reduces.
When this occurs in multiples in the same circuit, large to small to large to small to large again, the effect, especially if ocurring in a fairly short length of circuit, wreaks havoc on calculations.  Just mentioning that.

I do agree that "if it works for someone, its fine".... for the person its working for. :great:

Edit...darned spell check changes words to other words... but never corrects my poor spelling...heheheh
« Last Edit: August 09, 2017, 06:36:17 pm by MAN OF BLUES »

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Offline m in sc

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Re: How come we don't all install in-line fuel valves to block hydolock?
« Reply #252 on: August 08, 2017, 07:45:29 pm »
basically, yes, you are right... i didn't want to get too deep into it, but.... i have to size this stuff with my 2-strokes all the time.  its not pressure feed, but pulled through by a pressure drop. still... the point being is it will never exceed the the ability of the needle seats to flow in a gravity situation. which is being pushed by a column of fluid above it. (there is no pressure increase here.. column height is column height) the main jets can not exceed this. If they do, you need to upsize the needles and seats, have had to do this on some very high hp setups on the old stuff. (up to 3mm). this is why i didn't bother with giving diameters of the jets, which is usually in stock applications about 45-50% of the flow provided by the needle and seat at max. (keihin and mikuni follow this general rule of thumb when sizing).   

please, keep in mind, this is NOT an argument against vent over flows or the electric solenoid.