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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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#35 ·
I wonder if this is a high humidity issue. My '06 fuel sender works flawlessly and so does the same technology one in my '95 GPZ1100. Guess I'm happy to live in relative low humidity Colorado....

John
 
#38 ·
Fuel gauge sender problem fixed!!

Tried this "possible fix for the faulty fuel gauge" 2 days ago on my bike that has read empty after I fill the tank up then goes to full slowly after about 15 miles. It worked and now the gauge works as it should. Thanks Steppenwolf!
 
#40 ·
Thanks Steppenwolf!
You'll have to forgive him when he doesn't reply. Our friend Steppenwolf has been gone a bit more than a year now. RIP, my friend.:angelwin:
 
#39 ·
Since my bike was badly burned in a fire I 've had the opportunity (if you can call it that) to extensively dismantle and rebuild it...still in the process. Fortunately I purchased a Rick's tank sometime back and didn't install it at the time.

I've since fitted it and another complete fuel pump assembly. Before fitting this 'new' (second hand) unit I thought i would check the float to see if it was working properly 'electrically'.

Checking out both strips on either side of the fuel strip you'll find that one is plain and the other side a resistance strip. Both appeared to have a residue or light film coating over them probably from continuous fuel immersion? I cleaned both strips with a mild abrasive paper. I then got my multimeter and set it to the ohms scale. Placing a probe on either side of the fuel strips at the top most point I then slid the fuel guage sender float up and down the strip and noted changes in the resistance value from the top (least resistance) to the bottom (highest resistance). The fuel guage reads the resistance values not fuel.

I think removing the plastic base plate and soldering the contacts is a good idea. From the pixs posted initially it looks as though the pins are removed at the top plate and the base plate pulled down.

The epoxy worries me a bit as current fuels seem to dissolve most adhesives I'm aware of, especially if continually immersed.

At this time I don'r need to add another task to my rebuild list.

Is there a better method of securing the plate?
 
#41 ·
I am sure he will get my PM wherever he is.
 
#42 ·
I was a doubter for the magical mystery oil, however I did try it and after 93 miles my gauge became un-stuck. My float was hanging up just below the red indication. My guess is maybe the oil made it just slippery enough
 
#44 ·
ok, so after heaps of mucking around i have come up with something, my gauge has dead spots through the middle but it's not the strip thats the issue rather the two prongs either side as they dont seem to be putting enough pressure onto the strip so as to provide an easy slide action, i have bent them in harder but with to much pressure the float does not move at all so it needs just enough pressure, soldering them together is not the answer. maybe the float and srip design from he marine engine would be better if modified to suit.
 
#47 ·
Well i can confidently say that the gauge seems to be good as gold, i believe that the issue of the prongs not making good contact with the strip is the issue as it needs little resistance to be able to slide up and sown, i have been on the bike everyday since the fix and gone through 4 tanks and from barely reading the fuel level at all to now reading consistantly at all the levels i am happy with the results. it might just mean that the float needs to be disasembled and the prongs tweaked every so often .
 
#50 ·
Read the instructions for the Fuel Cap Remover/Installer in the attached pdf file. You will get the idea.
 

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#49 ·
Unscrew The Retaining Ring
 
#51 ·
Yup, that a pretty dumb question. Take it to the dealer if you can't follow the simple instructions.
 
#54 ·
I never got accurate fuel level readings, but my gauge is consistant(ly wrong!) showing me empty at 1/2 tank (refill at about 1.9 ~ 2.1 gal). I tried Seafoam and it made slight changes to my engine, it didn't help my fuel gauge. I'm beginning to think that the damn thing was designed by a frustrated fisherman!
 
#55 · (Edited)
08 NRS same problem

I have a 2008 NRS and my fuel gauge hasn't worked right since about the fourth tank of gas. I had it fixed under warranty and that lasted until a week after warranty ran out. I don't even bother looking at it anymore, just been using the trip meter. I called and was treated like I was stupid b/c this is a known issue with earlier model years. It is a known issue on my bike, which is the only one that matters to me. Is my fuel gauge the same as the one on earlier models? I haven't taken it apart yet, just asking before leaping.

p.s. Seafoam has worked great in all my stuff. gas engines 2/4 stroke, diesel, lawnmower, atv, tractor, truck, corvette, motorcycle all with no problems. This is the first fix I try when I have a fuel problem.
 
#56 ·
...Is my fuel gauge the same as the one on earlier models? I haven't taken it apart yet, just asking before leaping.

p.s. Seafoam has worked great in all my stuff. gas engines 2/4 stroke, diesel, lawnmower, atv, tractor, truck, corvette, motorcycle all with no problems. This is the first fix I try when I have a fuel problem.
No.

The 2007 and newer VRSC models have “non-contact” ultrasonic fuel level sending units. These have a different (and well documented) problem. Here's a few other threads that discuss it:

Thread 1
Thread 2
Thread 3
Thread 4

I don’t think “Seafoam” or any other cleaner will make any difference on your ultrasonic sending unit since there’s nothing to clean.
 
#57 ·
HD recently released a new fuel sending unit for the sonar bikes
 
#58 ·
I just installed a Rick's tank in my '04 and noticed alot of deposits on the resistive strip in the fuel sending unit. It was a dark brown film. I have only had 4 or 5 instances in which my bike showed empty when I knew it had fuel, happened at startup and the needle slowly rose to the correct reading. I cleaned the resistive element with carb/injector cleaner, real easy, I have a pic of the dirty vs clean resistive element and will post it later.
 
#59 ·
Here is a pic of the deposits I found on the resistive strip, left side is the way I found it and the right side after being cleaned. Used carb/choke cleaner, spray on and the residue wipes of real easy onto a clean rag, DO NOT use anything abrasive to clean this. When the resistive strip is clean, then shoot cleaner down the float where it rides up and down against the resistive strip, you can't get a rag in there to wipe so just move the float up and down to clean.

 

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#60 ·
Tnx sammy worked great for me....my gauge did read empty all the time, pulled out the whole sending/pump unit

disconnected/unscrewed the resistive strip and cleaned it with carb.cleaner, brakecleaner and a very fine sanding paper ( very soft rubbing with that).

gauge now reads good, hope it will do that for al long time
 
#67 ·
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