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Discussion Starter · #1 ·
Up here in the Northeast it's about that time to get ready for "the season"
Before I got going this spring, I wanted to get my V-Rod dyno tuned. Of course, I wanted fresh 93 in the tank and not 2-3 month old gas with Stabil in it when I'll be looking to dial in A/F ratio. I couldn't find any good procedure to drain the gas tank on this forum or anywhere on the internet.
Staring at the problem I came up with this.
It worked for me and may be useful for you. Proceed at your own risk. Keep all your fuel lines clean and don't forget about the fire hazard!!!

#1 Pull up the rubber skirt under your gas cap and expose the fuel lines. Locate your fuel out line, pinch the blue tabs to remove and push on a suitable hose and insert the other end into a proper container.
Fuel lines.jpg


#2 Locate the fuse for the fuel pump and remove it and save it to reinstall after you're done.
Fuel pump fuse.jpg


#3 Find an old or unneeded fuse and with plyers break it and remove one of the blades.
Fuse Blade.jpg


#4 Insert the single blade in the side of the fuse that the wire goes TO THE FUEL PUMP
Blade instert.jpg


#5 With the bike OFF, use a wire to jump from the positive terminal on the battery itself to the blade. The pump is grounded so no need to worry about the negative.

Jumper wire.jpg


The fuel pump will empty a full five gallon tank all the way to the bottom and rather quickly. Disconnect when empty. Done.
Collect.jpg
 

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EXCELSIOR
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I figured all you had to do was step one and turn on the key, the fuel pump will run till the tank is empty then turn off key because the system will never pressure up.
Does everything you've done without all the extra steps. What am I missing?
 

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I figured all you had to do was step one and turn on the key, the fuel pump will run till the tank is empty then turn off key because the system will never pressure up.
Does everything you've done without all the extra steps. What am I missing?
That won't happen actually as the pump only runs for 2secs when key is turned on, then the ECM removes the ground to the system relay until it sees life from the CPS. It is not based on pressure. However if you just ground out the the orange/green wire on the system relay it will then do as you say.
 

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Discussion Starter · #4 ·
I thought the lack of fuel pressure in the system is why it only ran for a second or two.
coastrider may be correct. There may be 5 steps in this process but snapping a fuse in half and holding a wire to it took all of 30 seconds.
Either way, it's cleaner and more efficient then a siphon.
 

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No, there is no pressure sensor in the system. When the ignition is energised the ECM sends a timed 2 sec ground output to the system relay activating the pump to prime the fuel rail. Then the system relay is deactivated until you crank the motor, then on receiving a signal from the CPS the ECM then returns the ground signal to the system relay activating the fuel pump again. This way if the engine is not rotating then the fuel pump has no power, for safety.
 

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Discussion Starter · #7 ·
Agree with Knut J lol.
coastrider has a much greater theoretical approach with a touch of finesse. I'm just swinging a hammer I guess.
At least anyone reading this will now have 2 options.
 

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#4 Insert the single blade in the side of the fuse that the wire goes TO THE FUEL PUMP
If I accidentally use the wrong side of the fuse, will I burn anything out or will the pump just not run? Like a USB plug, you have a 50% change it is oriented correctly, but you choose incorrectly 98% of the time. :)
 

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If I accidentally use the wrong side of the fuse, will I burn anything out or will the pump just not run? Like a USB plug, you have a 50% change it is oriented correctly, but you choose incorrectly 98% of the time. :)
It is much simpler to just put a ground wire to the orange/green wire on the system relay and turn the ignition on. The pump will then run permanently.
 

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I don't like combining electricity, half ass electrical connections and gasoline fumes. Just put a siphon hose in the tank, pull a suction with a hand operated vacuum pump and let it flow into a 5 gallon jug. I thought I killed myself once final defueling a jet using the one operational aircraft fuel pump using a static grounded ( I thought ) fuel hose from the engine to a grounded 55 gallon drum - after a couple minutes I heard a snapping sound, thought I had turned on the bad electric fuel pump but no, it was dry air static electricity snapping down the defuel hose. Panicked, I ran up into the cockpit to shut it all off. Was still snapping for a few seconds after shut off while I wondered why I was still alive and not on fire. Turns out ground wire must be spiraled around defuel hose, not simply run along side it. Lesson learned. Ride & Run the bike low on fuel, then refuel it with fresh 93 and don't worry about defueling it. If pumps inop. siphon it out. The less time you fool around with gallons of gasoline and electricity the better. I saw a pilot get burned to death by 100 octane once, he fell at my feet, and that's something you'll never forget - believe me.
 
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