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Fuel reserve not coming on

2K views 24 replies 7 participants last post by  gixerhp 
#1 ·
Hey guys, I've tried to check everything I could before posting this. I got stranded the other day by running out of fuel. It's 100 degrees (fahrenheit) here so it wasn't too comfortable in full riding gear pushing a 700 pound bike for two miles.
The fuel reserve light never came on. I've always filled up before the main tank is empty, but I let someone borrow my bike for an afternoon and apparently they went on quite the joyride, because they used over half a tank of fuel haha. I got stranded heading home from their house. I suspect it hasn't worked since I've owned it, because I never push it. I checked the white two pin connector inside the headlight as alanh has suggested, and checked the weird clip connector on the reserve tank. Both were clean and not corroded or burnt. I checked all connections around them too and added dielectric grease to all the terminals. The reserve light comes on when the key is turned as a test, so I know it isn't burned out. Any help is appreciated. I just really hope I missed something simple.
I will be draining the tank in the next couple days to put some braided fuel line and jiffy tite dry brake on, so it will be easy to test the reserve light at that point I would think.
Thanks!
 
#4 ·
Since the bulb illuminates at start-up its ok. And you did not find any corrosion or broken wires at the plugs.

Did you notice how many miles were on it since the previous fill-up? Do you zero one or both of your trip meters at fill-up?

Hopefully its just a dry-break issue. Most of the time a loose dry-break stops fuel from flowing from the top main tank into the underseat auxiliary fuel tank, in which case the sensor in the aux tank is exposed to air and the light illuminates as a result.

Since yours does not illuminate when you run out of fuel, it could be the sensor inside the aux tank is still wet (aux tank is full) or it could be the sensor has failed (its wire may have come loose). Its not common.

But I do not know if anyone here has ever located a source for the sensor itself, its only available from Yamaha with the fuel pump assembly.

The e-copy of the service manual has a sequence to troubleshoot. Might get a free copy around here, and hunt that path next.
 
#5 ·
Sorry for taking so long to reply. I completely replaced the fuel line and dry break from tank to reserve tank, and lubed and re-seated the breather dry break.
Checked all connectors and no corrosion on any. Still not indicating when I'm running on reserve. I think it is likely a bad sensor. That fuel pump assembly is rather expensive though. I'll keep my eye out for a used one.
I ordered a fsm on eBay too.
Thanks!
 
#6 ·
Sorry for taking so long to reply. I completely replaced the fuel line and dry break from tank to reserve tank, and lubed and re-seated the breather dry break.
Checked all connectors and no corrosion on any. Still not indicating when I'm running on reserve. I think it is likely a bad sensor. That fuel pump assembly is rather expensive though. I'll keep my eye out for a used one.
I ordered a fsm on eBay too.
Thanks!
Does your mileage tripF come on at all?
You may need to check continuity from the pump to connectors and to the headlight ect.

I guess sometimes the soldering inside the pump where the thermister is attached to it break loose. But the only way to know is to remove the fuel pump and inspect.
 
#7 ·
TripF is when you hit reserve and it counts down or something right?
Can I replicate running out of fuel to test this by disconnecting the dry break or will this create a vacuum?
To be honest it is very difficult to see the LCD readouts on my bike when stopped let alone riding, so I haven't noticed.
I will try to see if that is occurring.
Thanks!
 
#10 ·
Rudy you beat me to it!!
TripF is when you hit reserve and it counts down or something right?
Can I replicate running out of fuel to test this by disconnecting the dry break or will this create a vacuum?
To be honest it is very difficult to see the LCD readouts on my bike when stopped let alone riding, so I haven't noticed.
I will try to see if that is occurring.
Thanks!
You can disconnect the left side dry break and the bike will run off the undertank. But you need to protect the drybreak from rattling against the hot motor.

You can remove the top tank completely and still ride. To me this seems safer in the saddle.
 
#8 ·
When you first turn the key on, does the fuel light momentarily illuminate.

Do you notice on the gauge that the odometer changes from showing current mileage to showing miles traveled since the fuel light illuminated. It might be identified in the display as Fuel or as 'F'.
 
#13 ·
Yes the light illuminates briefly during key on.
I will check the tripF next time I ride it.
After that I would check if the sensor soldering has failed and attempt to repair it, but I don't have a garage so I ride it to my storage unit where my tools are. If it needs a gasket and I don't have one I would be stuck walking home or taking a Lyft/Uber, so just more of a covering-all-the-bases question.
 
#16 ·
Access to the tank is not easy (IMO). I believe battery box removal is necessary. My reserve was super clean , I wanted to see the sensor. My light was coming on too early. I found nothing with the switch, but re-routed the fuel ine from the front of the tank outside of kyles motormount, keeping it flat, and changed to a different dry break. I think the fuel was not feeding the reserve tank enough,(due to a slight rise in the fuel line) causing the light to come on. I would stop, and the fuel would fill the reserve, and the light would go off. I have clear fuel line now, so I can see if fuel is flowing. I could not remove the reserve tank. I think the oil tank has to come out too. Good luck, let us know what you find!
 
#18 ·
My bike seems to be running fine now, the fuel line must have had just enough rise to not allow gravity to feed the reserve tank. The clear line helps me see fuel is flowing too. You may try just looking in the reserve from the top and seeing if there is any rock candy or anything that looks out of place (broken soldering). There is a little nitch/indentation on the top that has to line up before the bolts go back in. Good luck!
 
#24 ·
Since this is a newer fuel thread I'll share this - I was having issues with my fuel light (doing the 8 blinks, pause, 8 blinks) and I had already gone through all the connections - no change. Detected low fuel one time, then left me stranded not far from home on the second tank without warning.

It's working now - I think my old sensor was corroded and not functioning correctly. When i pulled it last time I measured the resistance and it seemed like it was in spec; anyway, another unit replaced it and all is well. That means no wiring issues and my sensor was to blame; considering the crud lining my tank it isn't surprising.

Cheers,

Raz
 
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