Let's talk "low fuel level lights"

I wasn't referring to your lights. What I was referring to was your fuel tank and the vapors therein. You have to determine the low value with a multi-meter and a powered up circuit. Of course you'll have the assembly removed from the tank but it will be nearby simply because the wire harness isn't that long. I just want you to be careful so that you may continue posting and riding.

Yeras ago I had an experience with an empty 5 gallon gas can and a spark and they do go off real quick. A big wooooosh and she's gone.:D
 
Come on Flipper, Wrigles chewing gum. Sorry my speeling is atrocious. OK, 4.2 volts is empty.

Sightglass said: The is a spacific voltage for the sending unit when at empty, .5V using the Triumph hand held tool. The fix is to bend the arm to get this reading. It can be done with the tank in place, but a real pain in the stones. Bending the arem is the only fix, and it takes trial and error. Cheers
 
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Rocky:

I don't know about a pain in the stones. Most likely a pain in the ass. Why not use a pair of hemostats to reach in there and bend it?? I'm sure we all have those laying around from our roach burning days............................Your spelling is bad but not as bad a Gunshots by a long shot.:)

I've never taken the instrument apart to see if you can extract the offending bulb but I hear you can't. If indeed you can't what do you do when the backlight burns out? Get a new instrument? Hell, I've had my instrument for 57 years. It might be burn't out but I still piss with it just fine.........

Finally, I know what you meant...Wrigley's Spearmint Gum.....good stuff.
 
I just adjusted mine the other day. Not hard and it can be adjusted, but only so much. The first thing that you notice when you pull the sender/fuel pump assembly out of the tank is that there is only so far you can bend the arm and still have a working low fuel light. The design of the tank and the way the fuel level sensor sits in the tank, facing forward toward the front of the tank limits the amount of movement the sender has. My sending unit would cause the low fuel light come on when the sending unit put out 2.3 volts (the lower the sending unit arm sinks in the tank the more volts it puts out) but it doesn't happen instantaneously, it takes about 10 or 15 seconds before the fuel light would come on. Ideally you would want the sending unit to be putting out 2.3 volts when it is resting on the bottom of the fuel tank. But here is the problem, if you bend the sending unit's float arm too much it will hit the bottom of the tank before it can put out 2.3 volts and the low fuel light will never come on.

The way I adjusted mine was I removed the sender/fuel pump assembly from the tank. I then disconnected the fuel pump electrical connector so the pump wouldn’t be coming on when I reconnected the 4 pin connector that sends juice to the fuel pump and fuel level sender. After reconnecting the 4 pin connector I found the wire that carries the voltage coming from the fuel sender and hooked up a digital voltmeter and turned the ignition on. I then move the fuel sending unit’s float arm up and down and watch as the voltage output went up and down, the higher I lifted the arm the lower voltage output was. When I let the arm rest on the bottom of the assembly the voltage was something like 2.6 volts. I then raised the arm and slowly lower it until my low fuel light came on and this is how I determined that if the sending units voltage hit 2.3 volts or more the low fuel light would come on.. I then bent the sending unit’s float arm slightly so the voltage output would read 2.3 volts when it was slightly raised above the bottom of the assembly. I raised it slightly to take into account the thickness of the bottom of the tank where the assembly bolts to the tank so it will read 2.3 volts. After putting it all back together I filled the tank and then went for a long ride. Prior to the adjustment my low fuel light would come on at 130 miles or so. After the adjustment it comes on at just under 160 miles.

The best way to calibrate the fuel sending unit would be to have a bottom section of a beat up damaged fuel tank that you could cut the top section of the tank off and then bolt to the sender/fuel pump assembly to it. That way you could insure that the sending unit was putting out 2.3 volts as it would rest installed in your tank.

If you want to do this adjustment pick up a few things from your dealer first. 2 new crush washers for the fuel line that bolts to the bottom of the fuel pump assembly and a new rubber seal that goes between the fuel pump assembly and the fuel tank. You might also want to get a new fuel filter if you bike has some miles on it as the filter sits on the fuel pump assembly and you’ll have easy access to it while the pump is out of the tank.

One word of caution, be careful when you are removing the fuel pump assembly out of your tank. The fuel sending unit’s float arm is easy to damage and will get caught on the tank as the fuel pump assembly is being pulled from the tank.

Also, if you decide to try this you do so at your own risk. I’m not a mechanic just a guy who fixed something that Triumph should have. If you break your bike or burn your garage down don’t come crying to me.
 
That's a good play-by-play. I take it the float rests on the bottom of the tank forward of the assembly? Since the tank is 18 gage cold rolled AKDQ (aluminum killed drawing quality) steel, would it be possible to set the assembly on a flat surface and put a brass or steel 18 gage shim under the flaot end to calibrate it?
 
I just adjusted mine the other day.....................

Azccj,

Thanks for the thorough write-up. Everything you did seems to be within my comfort level for working on a bike. I'll give it a try, maybe this winter once the bike is napping. :)
 
What, no SAE number?

Since the tank is 18 gage cold rolled AKDQ (aluminum killed drawing quality) steel.................

Sheesh Flip!!! At least you could give us the SAE number for the sheet metal. What do you expect anyone to do with such a vague specification? :D
 
Sheesh Flip!!! At least you could give us the SAE number for the sheet metal. What do you expect anyone to do with such a vague specification? :D

Well, in as much as the tank is hydroformed in Taiwan, the only way I could get chems on the tank would be to plasma cut a section out of mine and send it off for a spectroanalysis or spark test it and I'm not gonna do either. Somehow I don't believe Triumph is going to give me the grade. That's proprietary data.

I know it's AKDQ drawing quality, most likely 50X-Cabinet Quality, that can be ascertained by looking at the amount of draw, the surface quality and the amount of deformation but the SAE grade would be conjecture without destructive testing. I didn't spend 18 odd years working around steel not to be able to identify a grade by the in-use properties.

It works, it holds fuel, it readily takes a comercially acceptable top coat and it don't leak. The key is the gage. It don't matter what material you use for the benchmark shim, whether it's ferrous or non ferrous or even plastic. It's the thickness that is important.

Per chance do you want to 'donate' your tank?:D
 
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