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Possible fix for older fuel gauges.

102K views 114 replies 67 participants last post by  michael morgan 
#1 ·
Gas float fix

Well, this is as good a place as any to post this. Here's the problem IMO:

The gas gauge (pre-07 at least) is a long resistor strip with a float. The float has two contacts - one on each side - that run along the resistor strip, thus changing the resitance reading which is interpreted as your fuel level. In the past, peopl have tried to fix erratic reading by taking Scotch-brite to the resistor strip, with the theory being that the strip was getting 'gummed up'. This helped at times - but sometimes not, and not for long. We were barking up the wrong tree.

If you pop the bottom off the float (it is glued or plastic-welded) you will find that the two contacts are separate pieces - one for each side. Now this is the important part: THE TWO PIECES ONLY LAY ON TOP OF EACH OTHER UNDER THE FOLAT BOTTOM (see pic with my hand in it) In other words, the circuit depends on thos two piece of metal laying on top of each other (!!!!!) There is NO connector or screw to secure the plates and ensure they stay in contact (double !!!!!!!!!!).



When I took my float apart, I found that the two contact plates (brushes) were discolored from time and fuel exposure - including where they overlapped and were supposed to be closing the circuit. I cleaned them up and placed a TINY drop of solder to hold them to each other. (Disclaimer - I have NO idea if solder in your gas is a BAD idea, but the amount was tiny and then I slathered the whole thing in epoxy to glue the float back togther.

So far, so good! But what a terrible design...

 

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#2 ·
Alex this was a very good post so I cut a copy of your post out so it wouldn't get lost.
 
#3 ·
My gauge better keep working then... :) And you could've at least fixed the typos...

Again, I emphasize that the two pieces were just laying on top of each other - not even glued to each other. Just the bottom plate of the float supposed the keep them pressed together. Sort of like trying to wire a circuit by stripping wires and then just setting them on top of each other and laying a book on top.. This approach for a circuit that is going to remain immersed in gas!!! :chair:

Despite the fuzziness of the pics, you can still see how discolored the contacts were - on an '06 with about 12.5k miles.
 
#46 ·
Don't waste your time



Harley designed the part and showing them a good fix rather than them being able to sell you a whole new sending unit is not in their game plan. They stopped listening to customers and employees regarding issues like this right after the 100th. They'd already made their money.
 
#6 ·
From when I bought my 03, around 7,000 miles on it to about 11,000 miles my gauge never worked.
Last winter I ran Sea Foam through the thing and my fuel gauge has worked ever since. Now at almost 16,000. I will say I still set the trip just in case, but it seems to function dead on now...
 
#12 ·
Has anyone else tried this fix? I'm looking for a follow up report.

Thanks.

RJ
 
#84 ·
Has anyone else tried this fix? I'm looking for a follow up report.

Thanks.

Yes, I have used this fix and it has worked on my bike for 4 years and counting. Be very careful when working with the large opening of the fuel tank exposed and disconnect the maxi fuse before you start work. Not a bad idea to cover the opening,have a fire exingisher,and maybe work outside if possible and not raining.

Sea foam is good to through in you fuel tank for storage and I do notice a tendency for the fuel gauge to stick for the first rides of the season after sitting for 5 months.
 
#15 ·
Been reading about these problems a bit and I don't have the problem BUT oxide on Copper is conductive, shouldn't be a problem. Is the plating on those contacts copper ?

John
 
#17 ·
I believe the are Brass not Copper
 
#20 ·
Sea Foam...

I am not a mechanic, can barely get through changing the oil on my '04 VROD in under two hours so I am not sure if I want to A) try this fix on my own or B) pay someone at Harley to fix my gas gauge if I can use the Sea Foam.

I appreciate the link to the Sea Foam site but I was not able to find anything that specifically talked about motorcycles or how much to add to a motorcycles talk of gas?! They did say about 1 ounce per gallon. Is this 1 ounce per gallon recommended for the VROD as well? And it says when the engine is warm.

So maybe fill up the tank, drive around for a few miles, then drop in 3-4 ounces, wait five minutes, and then start the engine again? I am nervous about this so I wanted to post for some reassurance before attempting this.

Thank you ahead of time. First time on the site, first post, but excited now to read through the threads. I have had many small issues with the bike now over the years and the gas gauge not working is just the latest. I am happy I hopped online to google some questions-this looks exactly like the site I was hoping would exist!

smerks
 
#22 ·
I've used Sea Foam alot in all kinds of things including my bike. I don't know if it helps all the thing they claim, but its never hurt anything. All auto parts stores carry it.
 
#28 ·
I have used both Sea Foam and Marvel mystery oil. IMHO the marvel mystery oil worked better on the fuel level sensor than the sea foam did.
 
#29 ·
You used Marvel Mystery Oil on your bike & it didn't mess up the sensors etc? Years ago my buddy put that in his 1988 Camaro 305 V-8 & afterwards it never ran right again... He eventually sold the car... so frustrating.
 
#30 ·
there are no sensors to mess up using Marvel mystery oil in the bike
 
#31 ·
Hey Hal64HD:

What is a "30 Tooth HDI Sprocket"?

Did you lower your rpm's in 5th gear by switching your sprocket?
 
#33 ·
I actually have an 07 CD that is doing this. Except it has a miond of its own at times. Once time going down the road I actually watched the fuel gauge go back up to full. (never knew you could make gas go into your tank while going down the road) Mine will stick... then un stick... I use to work in Auto Parts over 10 years ago and I can remember when we first got Seafoam in. It was new to the area. Someone put their Oil Solution in and it hand grenaded the 454 ( guess it cleaned it out too good ) So I know the stuff cleans real well (bad thing was I was the one that sold the can... and sold it to the family farm so i was stuck between a rock and a hard place on this one.... blame was going back and forth... but anyhow) They make a good product. I know my bike seems to be doing the same as the Pre 07's....Guess I will try it and we will see.
 
#34 ·
Just came up with another problem with my resistor strip, namely a dead spot. About 80% into a tank of gas my gauge drops to zilch then 10 miles or so comes back alive. Metering out the strip I found a dead spot about 2 inches from the end of the strip. No conductivity whatsoever. Won't take solder either. Don't know what to do about it. New one costs $200.
 
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