Aftermarket fuel gauge?

Hi guys, I hate having to guess when I am running low on fuel, is there anyway I could make/mod a gauge to work with my bike? Any ideas or ways would be great.

 

Ok, not all at once lol.

I came up with this...



but theres a few problems running through my mind, if the whole thing is submerged in gas, will the gas conduct the electricity and make the light stay on? Is there any risk of shock?

And more flaws please point out.

 

Bigger problem is when tank is almost empty, contacts close, spark -----

You really won't need an indicator light.

 

lol ya, that's what I was worried about...

 

Hah, wow...
Good incentive to keep her topped up.

 

Fuel gauges are problematic in many ways... first they're measuring small volumes that slosh around way more than a car so they're accuracy is mediocre at best. Secondly, they're not that easy to find/install and even when you have it installed running the gauges isn't that trivial.

I really recommend instead learning how to use the odometer. You have a reserve for a reason -

Figure out the approximate fuel milage of the bike. Fill the tank and go for a normal ride. Fill the tank again. Divide the odometer reading by the lires to get km/L. You know the tank is either 10L + 3 reserve or 15L + 3 L reserve. So - if you get 15km per litre then on a 10L tank you'd get about 150km before reserve and up to 45km on reserve.

So - zero the odometer each tank - (with these numbers) when the odometer reads 100km you've used about 2/3 of the tank. You know that when the odometer approaches 150km you're near reserve and should start planning a fuel stop in the next 30-40km.

I trust my odometer far more than I trust my factory fuel gauge (a warning light) and I'd trust my odometer far more than a home brew gas gauge.

Just my HO.

 

Alright then, odometer it is!

 

Don't take my word for it... I'm a grumpy old man who just wants to hear his own voice

Try it and see how you get along with it... nothing wrong with inovation

 

Instead of using voltage, you should measure resistance. The sending unit on my turbo uses a similar idea with the float. The float rises and lowers with the gas and moves a wiper across a potentiometer. A resistance measurement would then indicate fuel level. Big plus is no spark.

You still have all the other issues with gas sloshing around etc. The gauge is only good when you first start the bike and you can see roughly how much gas is in the tank. For the time and effort, the odometer idea is your best bet in my opinion.

 

Ok, thanks for the help guys.

 

The wiper measuring resistance method is the most commonly used method for a reason. No spark (provided you wind the coils close enough) even with current flowing through the wires. Your idea has merit but I would think it unwise given the arc/spark as the contacts close. Not a good thing in/on/around gasoline. Yes, I know you need oxygen to sustain combustion but just imagine what would/could happen if the bike fell over. Go with the resistive wiper.

 

I've actually been thinking about this idea for a while but haven't had the time to work on it (among other projects) for a number of reasons - not the least of which is riding my Seca to work each day. ;-)

The best thing I can come up with is use three thermistors on a long board - one for Full, one for Half, and one for Empty. (Or Reserve if you prefer.) As the gas drops past each thermistor it changes temperature - it gets warmer - and the resistance changes which will allow you to trigger a light or something else. All this could be dipped in a light coat of gasoline safe plastic to protect the thermistor.

You don't even need to use a complex microcontroller or anything either. If you set up a simple resistance circuit where the "cold" value of the thermistor is high enough to prevent an LED from lighting then you could just use three LEDs.

Best of all - no sparks!

This doesn't help you with sloshing and would be useless in winter. However if you're not keeping 3/4 of a tank riding in winter then you're asking for your tank to frost anyway.

 

I know that I have about 20-25 miles remaining when I switch to reserve. That way, it doesn't matter if I forget to reset to zero, if I don't fill up all the way, or if I forget. I DO have to remember to put the petcock (heehee, he said "pet cock") on RUN whenever I put gas in. Then.......ride 'til I hit reserve. Now I gotta get gas in less than 30 miles.

easy. Plus, if I ever DO want to get an indicator, I have a 750 tank on my 650 so all I'd have to do is hook up the circuitry and install a gauge.

fwiw,

dave

 

Unfortunately those of us with Secas don't have a lot of tank swap options short of custom sheetmetal as the Maxim tank would look mighty weird on a Seca in my opinion.

 

550 Seca has a fuel guage. Any way to find one of these and install in your bike?

 

Y'know I did think of something else while working on my dad's Honda - his CB550 Four has a gas gauge in the cap that is spring loaded and has a float attached to a chain at the bottom.

As the tank empties itself the float drops lower pulling on the spring and moving the indicator.

A neat little mechanical system with many flaws but one that could probably be replicated by someone with a little tinkering ability and a spare gas cap.

 

put a "T" off your fuel line and run some small clear plastic line up the triple clamps someplace, cap it and have a very small vent hole

 

So kind of like the home-made carb sych tool then? As the "offshoot" line drains so drains your tank. I'm not sure how that would work. Wouldn't it drain the offshoot first?

The only thing that I could think that would make that workable would be a thumb valve on the end that you could custom-set the amount of "leak" in the offshoot and match that to how fast the tank drains.

This does bring up another idea. You could use a vacuum gauge like one of the sensitive 0 - 10 psi ones. Drill a hole in the gas cap (or in the tank if you're so bold), mount a vacuum nipple and hose to it, make sure the gas cap seals, and then attach the hose to the vacuum gauge.

Not all that pretty but it would work.

 

if the carbs sucked the fuel from the tank, it might drain the offshoot first but they are gravity feed, if the tank was almost empty it might
i saw it one time at a antique tractor show
no vacuum gauge, the tank needs to be vented

 

Ahhh! That makes much more sense to me now. Thanks for clearing that up!