Reserve fuel question

[Dialtapper]

Last couple of rides when the low fuel light would come, engine would start to cut out, go to reserve.

No problem, for maybe 20 seconds, engine would start to cut out again. Recycle reserve switch, runs good, cuts out again.

Nursed to next gas station.

Any ideas?

 

[Karmakatt]

Had same problem. In a hard start off a line the light comes on, the oil light comes on and I miss shift. She starts to bog than I switch it to RES. It gives me enough for half a block than cuts out and I switch to ON and get another 1/2 block than hit RES and blah blah make it home. Pick up some fuel in a Gerry Can, run it in On and never had a prob since..

That's just me..

Karma

 

[Traumahawk]

Ive got the same problem...Ive wondered if its bad fuel...becuase afterward had to run some sea foam thru it to get it running right.

 

[jfeagins]

Don't the fuel pick up from the very same place regardless of which setting you have selected on the handlebar switch? Difference being - when the sensor detects low level and turns on the red light, the pump quits running?

 

[Dialtapper]

Don't the fuel pick up from the very same place regardless of which setting you have selected on the handlebar switch? Difference being - when the sensor detects low level and turns on the red light, the pump quits running?

Damn good question.

I thought it's like every other bike I've owned, reserve is the very bottom part of the tank. It makes sense that that water and crap have settled there and that's why it doesn't want to run when you go to Res.

If you read my post under "Motor" and "Hard to start cold" both these problems started at the same time. Are they related? Sounding like it.

Anyone got a definitive answer on how reserve works on a VMax?

 

[DMAN999]

The reserve just turns the fuel pump off when the sensor in the tank is dry (fuel level is below it).
That happens with about .8 gallons left in it.

 

[jfeagins]

Again, I believe there is only the one fuel pick up, and it is at the very bottom of the tank, drawing from the lowest point at all times. The fuel sensor falls short of the bottom, and when dry, turns on the fuel light - at which time the pump shuts off - to remind everyone that it's time to fuel up. Then, when you switch over to reserve, you are bypassing the low fuel warning system, and restarting the pump to continue using that last .8 gallons.

 

[[email protected]]

Make sure you are using the switch properly. I made that mistake before.
ON is normal position
RES is when the fuel light is on.

 

[johnpclynch]

Again, I believe there is only the one fuel pick up, and it is at the very bottom of the tank, drawing from the lowest point at all times. The fuel sensor falls short of the bottom, and when dry, turns on the fuel light - at which time the pump shuts off - to remind everyone that it's time to fuel up. Then, when you switch over to reserve, you are bypassing the low fuel warning system, and restarting the pump to continue using that last .8 gallons.

Correct, so guess what happens when there is a bad connection in the bypass circuit? the pump won't turn on
When you switch back to "On" it has the same effect as turning on the ignition - the pump will run for about 10 seconds, filling the carbs, but disengages again because the reserve light is on

So... check for a bad connection between the reserve switch and the fuel pump relay

 

[Traumahawk]

So... check for a bad connection between the reserve switch and the fuel pump relay

I was laying in bed thinking about this...thanks for confirming.

 

[jfeagins]

Correct, so guess what happens when there is a bad connection in the bypass circuit? the pump won't turn on
When you switch back to "On" it has the same effect as turning on the ignition - the pump will run for about 10 seconds, filling the carbs, but disengages again because the reserve light is on

So... check for a bad connection between the reserve switch and the fuel pump relay

Yes. Thank you for inserting the rest of the story on our reserve setup. :clapping:

My point was that hitting reserve, then flipping the switch was not going to cause the pump to begin picking up bad gas from the bottom of the tank. I should have gone further in my explanation.

 

[Dialtapper]

Correct, so guess what happens when there is a bad connection in the bypass circuit? the pump won't turn on
When you switch back to "On" it has the same effect as turning on the ignition - the pump will run for about 10 seconds, filling the carbs, but disengages again because the reserve light is on

So... check for a bad connection between the reserve switch and the fuel pump relay

That is exactly what it it doing, running for about 10 seconds and cutting out again, thanks.

Do you know where about to start looking for the fuel pump relay?

 

[Traumahawk]

Hmmm well I took off the airbox, and then the carbs the other day...I wonder if I couldve jostled a wire going to the relay...or else something just doesn't have good connection anymore, after I bumped it.

 

[jfeagins]

Square black box located under the left hand scoop.

Find a VMX12 service manual. There may be one posted around this forum some place. I believe it contains a "how to" section for testing this relay.

 

[DMAN999]

Here's the Haynes Manual:
https://dl.dropboxusercontent.com/u/55030067/Haynes%20VMax%20Service%20Manual.rar
And the Factory Service Manual:
https://dl.dropboxusercontent.com/u/55030067/VMX12 Service Manual.pdf

 

[johnpclynch]

#1, make sure there is power getting to the switch (Red/White)
#2, when switch is in "Res" make sure it is sending power to the relay (Red/Green)
#3, check if the power is getting all the way to the relay behind the left scoop (Red/Green)

 

[Dialtapper]

Here's the Haynes Manual:
https://dl.dropboxusercontent.com/u/55030067/Haynes VMax Service Manual.rar
And the Factory Service Manual:
https://dl.dropboxusercontent.com/u/55030067/VMX12 Service Manual.pdf

Thanks, much appreciated!