This is kinda old, seeing as it dates wayyyyyy back, but the 1/4w. Resistor thing is more dependant on the resistance value ( ohms) than the wattage...
It was found that a 220 ohm value seems to work close, but is still not adjustable... to truely make it adjustable you need a variable resistor, or pontiameter...
Radio shack has a 3/4watt 220 ohm unit for about $2, which does allow you tto trim the gauge correctly and to the point you want.
Its in the COG library, for those of you with current membership, and can be found here
http://cog-online.org/clubportal/clubstatic.cfm?clubID=1328&pubmenuoptID=30728Sorry, you had to be a member to read it, but it goes thru installing one...
It allows you to adjust the sensitivity of the gage sender unit to allign it when the level is right at reserve... and it has worked for 20 years or so...
I'll probably get slammed for posting this, but its worth reading...
Article By: Dave Cavanaugh
Fuel Gauge Adjustment
Go to Radio Shack and get a multi turn 1000 ohm .75 watt variable resistor (or "trimmer"). Part # 271-342 $2.49
http://www.radioshack.com/1k-ohm-15-turn-pc-mount-cermet-potentiometer-trimmer/2710342.html#.VT_sj7PD-AgEditor's note: a number of riders have been successful with a 220 ohm resistor instead of going through the trouble of fiddling with the variable model.]
Solder leads six or eight inches long, number 18 wire, to the center and one of the outer pins. Doesn't matter which as long as one is the center lead. Attach the resistor and leads to something so the pins don't get damaged (see below). Put some shrink tube on the solder joints so people won't think you're an amateur.
Remove the two bolts, raise the back end of the gas tank and fish out the plastic connector you disconnect when you remove the tank. (Jam a block of wood or a wadded up towel under the tank to hold it up. If you raise the tank too high, the black rubber knobs under the front of the tank will probably fall off.)
Disconnect the plastic connector, and temporarily jam the stripped ends of the two leads from the resistor into the two holes in the female side of the connector, and reconnect. You want the resistor to be in PARALLEL with the sending unit.
I made my trial pigtail long enough so the resistor stuck out a couple of inches between the seat and the gas tank, and messed with the adjustment over two tanks of gas or so.)
Ride (or drain the tank) until you switch to reserve. Use the small screwdriver you use to adjust your eyeglasses to adjust the resistor. Adjust slowly; the gas gauge is heavily damped and doesn't move very fast. When the needle is where you want it, you're more or less done. (I adjusted mine so the gauge is just touching the red square when it hits reserve).
Once it's adjusted you can solder the resistor wiring into the main wiring below the connector permanently. That way, when you remove the tank, the resistor won't come out.
You should attach the resistor and leads to a piece of circuit board or thin piece of wood to protect the pins (I used a tongue depressor because it was handy). I used little wire ties. Hot glue would work, too.
Dave
[Editor's note: put a dab of silicon on the adjuster screw. This should stop it from adjusting itself from the bike's vibrations.]
This was gleaned from
Article By: Dave Cavanaugh
