Kawasaki Vulcan Forum banner

661 - 680 of 729 Posts

·
Registered
Joined
·
10 Posts
Hi

Oh well, im the "Lets just do it" kind of guy.

Took the instrument off of the bike today, unplugged the fuel sender connector and verified that it is indeed pin 13 & 16 that goes to the sender.

Found 2 solder spots on the PCB, inside the speedometer housing that was connected to those 2 pins and added one 220 ohm and one 47 ohm resistor in series across the 2 solder spots.

Have put the bike back together and will report back if this makes the fuel gauge more precise than before.

Use at own risk.

PS. When i confirm that it solves the problem, i am going to glue the resistors to the PCB to avoid them shaking loose.
 

Attachments

·
Registered
Joined
·
21 Posts
Can someone post the pictures on when it is all connected up on the bike? I do better with looking at a picture than trying to follow an explanation in words.

thanks
 

·
Registered
Joined
·
74 Posts
Found this "This Indication comes from the fuel level indicator inside the tank. This is a float that "floats" in your fuel (like the float in your toilets). It is attached to a potentiometer (variable resistor), who's resistance increases as the float sinks.

Bike voltage (12V) is shared between the float potentiometer in the tank and the fuel gauge you look at.

With a full tank, the resistance at the float potentiometer is zero, so the gauge gets the full 12 volts and indicates a full tank. As the float potentiometer rotates, it increases in resistance and takes some voltage away from the fuel gauge, so it's reading drops.

The design problem with the 900 is that the resistance of the float potentiometer is too high in its middle section, so it takes too much voltage too soon (half a tank), causing the gauge to read empty too soon.

By putting a 260 ohm resistor in parallel with the potentiometer (Tamj's solution), we lower the potentiometers effective resistance and the voltage it takes, causing the fuel guage reading to drop off slower. But the size of the resistor works opposite to want you would think. A resistor smaller than 260 ohms, put in parallel with the float potentiometer has the effect of lowering the potentiometers effective resistance even more (it's an inverse relationship). This will cause the fuel guage to drop off even slower.

What I am going to do is run my bike to the point that I want the gauge to read empty (1/2 gallon) and then I will play with various resistances to get it exact. My guess is that a 240 +/- ohm solution will get me where I want to be.

This is not meant to take away from Tamj's solution. It will correct the gauge to read empty at 1 gallon, as Tamj stated." Got it Thanks
 

·
Registered
Joined
·
37 Posts
how much gas will be left in the tank before the gas light comes on? i was down to about a 1/2 a gallon left in the tank. Im guessing the 900 has about 4 gallon tank. anyone know whats going on? i put on a 260 ohm resistor. No idea if that should effect the gas light.
 

·
Registered
Joined
·
761 Posts
how much gas will be left in the tank before the gas light comes on? i was down to about a 1/2 a gallon left in the tank. Im guessing the 900 has about 4 gallon tank. anyone know whats going on? i put on a 260 ohm resistor. No idea if that should effect the gas light.
The bike has a 5.3 gallon tank.Last week when my low fuel light came on I rode an additional 20 miles then filled up.It held 4 gallons.
 

·
Registered
Joined
·
10 Posts
Quick update

I drove 224,4 kilometers on the bike, the fuel gauge position can be seen on the picture and i was able to put 10,5 liter's into the tank.

Did not dare drive any longer before refuelling the first time after i modified the fuel gauge, but now i know that i will not run out and will try to get it even lower next time.

Was pleasently surprised at the 21,4 km/l (50mpg) fuel consumption. Most miles was done on 80kph roads with a small trip to the motorway.

I dont know if the low point is going to be right, but right now i would suppose that i would need to adjust the resistors as the tank is more like 1/4 full on the gauge, but nearly 1/2 full in reality.

Most important is that "empty" means "Damn near empty, refuel now you fool" :)
 

Attachments

·
Registered
Joined
·
37 Posts
The bike has a 5.3 gallon tank.Last week when my low fuel light came on I rode an additional 20 miles then filled up.It held 4 gallons.
Ive never even seen my light come on. and ive ridden when it was pretty low and put 4.5 gallons of gas back into it. ive owned the bike for almost 2 years and i still have yet to see it come on. i should get a small gas can and keep it in my bags and just wait and see if and when it comes on and how far i can go.
 

·
Registered
Joined
·
7 Posts
Installed a 270 ohm 1/2w resistor today but didn't notice a difference. Was at about 3/4 before and after the resistor. Tested the resistor and confirmed it's good, at about 266 ohms. Installed by pushing the resistor ends into the plug connector as show on a few photos here.
 

·
Registered
Joined
·
166 Posts
This mod has worked for me. Reads alot better now, still isn't perfect but 100 times better than what it was.

Fuel light now comes on just as the needle reaches E.
 

·
Registered
Joined
·
46 Posts
Hi guys and girls wastedthelight can't see any pics . My fuel gauge is doing me head in , would love to know how to fix it , any way you could repost pics


Sent from my iPad using Tapatalk
 

·
Registered
Joined
·
507 Posts
Installed a 270 ohm 1/2w resistor today but didn't notice a difference. Was at about 3/4 before and after the resistor. Tested the resistor and confirmed it's good, at about 266 ohms. Installed by pushing the resistor ends into the plug connector as show on a few photos here.
The magic "268.8972 ohms fixes it" (or whatever the number is) figure presumes a level of precision in that fuel gauge potentiometer that ....uhhh..... "probably" doesn't exist. Even if that potentiometer was made to 5% tolerance -- which, LOL -- it would still leave you with about 13 ohms of variation on either side. More likely, it's in the 20% or even higher tolerance range, so 50 ohms plus or minus at least.

It's going to be one of those "try/fail, try/fail, try/success" deals with various values if you really want to get it spot on. On one bike it might be 350 ohms, on another 250, and another guy might even be scratching his head wondering, "What fuel gauge problem?"
 

·
Registered
Joined
·
166 Posts
Think I'll just stick to resetting the trip meter and fuel up when it gets to 145 miles that's accurate enough for me ??


Sent from my iPad using Tapatalk
I just had my fuel tank up doing a coolant flush and could have taken photos for you.

Well worth doing the mod make the fuel gauge work so much better and is easy and cheap to do.

No need to get the exact resistance just some where in the ball park is fine.
 

·
Registered
Joined
·
73 Posts
I tried the fix but do not see any difference.
Thing is my low fuel light functions , it remains steadily on at about 270 kms but the again the needle has a mind of its own.
as it gets below the middle, sometimes it goes to full when moving then slowly to empty then to the middle or 3/4 again, even when light shows empty.
So I removed the resistors and will be only using the light.
 

·
Registered
Joined
·
95 Posts
My low-fuel light comes on consistantly at 180 miles + or - 1-3 miles according to the trip-odometer. I ride to 200 miles on the on the odometer and fill the tank. It always takes around 4.3 gallons which supposedly leaves me with a gallon or 45 more miles if I needed it. That seems like a comfortable cushion to me. Simple.
 
661 - 680 of 729 Posts
Top