Harley Davidson V-Rod Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
63 Posts
Discussion Starter #1
This may be a REALLY dumb post, but this morning I was low on gas and the power was all over the map. (I have a 2008 VRSCDXA.) When opening the throttle, the power would come up, lose all power and then come screaming back.

At the time, I guessed that I must have been very low and the gas was sloshing from the front to the back of the tank causing an intermittent loss of fuel. When I filled up, it only took 4.4 gallons. I wouldn't have expected to have this problem with more than 1/2 gallon in the tank.

The only theory I have on this is that when I filled up, the tank is not getting completely full. So, what do you think of this theory? Also, when HD says that it has a 5 gallon tank, does that measure to the very brim of the tank or does it account for the gas nozzle shutting the gas off some distance below the top?

Thoughts?

PS - I have more fun on my VRSCDX than I ever had on my Z.
 

·
Premium Member
Joined
·
11,245 Posts
Sounds like you have a leaky hose somewhere in the gas tank. When fuel gets below the hole you start losing pressure. The fuel pump keeps 62 lbs pressure to the fuel rail.
Borrow a Fuel pressure gauge from a local Autozone etc and hook it up the the Schroeder valve on the right side of the engine and look for 62 lbs nominal pressure. DO this when the tank is almost empty and the problem is there.
 

·
Premium Member
Joined
·
11,245 Posts
Another way to test is to remove the pressure side fuel line and hook up a length of hose to the nipple on the top of the tank. Blow real hard into the hose. It should be sealed and you should not be able to expel air into the tank. If you do then you got a leak.
 

·
Registered
Joined
·
63 Posts
Discussion Starter #4
Thanks for the insight Rusty!

Another way to test is to remove the pressure side fuel line and hook up a length of hose to the nipple on the top of the tank. Blow real hard into the hose. It should be sealed and you should not be able to expel air into the tank. If you do then you got a leak.
I assume that I should be doing this when the bike is low on gas and having the power fluctuation problem...
 

·
Premium Member
Joined
·
11,245 Posts
Thanks for the insight Rusty!



I assume that I should be doing this when the bike is low on gas and having the power fluctuation problem...
It would be easier but not necessary. The system should be sealed so you should not be able to blow air into it.
 

·
Registered
Joined
·
11 Posts
This may be a REALLY dumb post, but this morning I was low on gas and the power was all over the map. (I have a 2008 VRSCDXA.) When opening the throttle, the power would come up, lose all power and then come screaming back.

At the time, I guessed that I must have been very low and the gas was sloshing from the front to the back of the tank causing an intermittent loss of fuel. When I filled up, it only took 4.4 gallons. I wouldn't have expected to have this problem with more than 1/2 gallon in the tank.

The only theory I have on this is that when I filled up, the tank is not getting completely full. So, what do you think of this theory? Also, when HD says that it has a 5 gallon tank, does that measure to the very brim of the tank or does it account for the gas nozzle shutting the gas off some distance below the top?

Thoughts?

PS - I have more fun on my VRSCDX than I ever had on my Z.
 

·
Registered
Joined
·
11 Posts
Man I had the exact same thing happen to me on my 2012. I was cruising along the highway and I was getting this power surge, but fuel gauge read I still had a quarter tank left. I was actually bone dry.had to call my son to bring me fuel.
 

·
Registered
Joined
·
92 Posts
Man I had the exact same thing happen to me on my 2012. I was cruising along the highway and I was getting this power surge, but fuel gauge read I still had a quarter tank left. I was actually bone dry.had to call my son to bring me fuel.
Gauge is piece of shit, i never trusted, as soon that i reach the last quarter, I fill the tank!!
 

·
Premium Member
Joined
·
11,245 Posts
I thought I would mention, I ran out of fuel on my 2007 VRSCX with 5 gallon tank. I coasted into a gas station where I pumped 5.2 gallons into it.

Not saying you have a 5.2 gal capacity only that is what I pumped.
 

·
Buy American!
Joined
·
3,960 Posts
The problem described indicates a loss of fuel on the suction side of the pump, not the pressure side. The fuel hose will leak just as much when under the fuel as it will when its not under the fuel.

The only attachment on the suction side is the sock. It is less than 1/2" tall. The OP is out of gas at the point when fuel starvation occurs.

Don't run it that low and expect that the fuel will be at the suction port under high Gs.
 

·
Premium Member
Joined
·
11,245 Posts
Wasn't there a problem with plastic parts in the sock breaking and causing a blockage on some model of V-Rods. I seem to recall that.
 

·
Premium Member
Joined
·
11,245 Posts
The problem described indicates a loss of fuel on the suction side of the pump, not the pressure side. The fuel hose will leak just as much when under the fuel as it will when its not under the fuel.

The only attachment on the suction side is the sock. It is less than 1/2" tall. The OP is out of gas at the point when fuel starvation occurs.

Don't run it that low and expect that the fuel will be at the suction port under high Gs.
He was having problems with 1/2 gallon left. I regularly run to that point and less without any problems.
His best bet is to get that fuel pressure gauge I mentioned and test it at the fuel rail.
 

·
Registered
Joined
·
63 Posts
Discussion Starter #15
Another way to test is to remove the pressure side fuel line and hook up a length of hose to the nipple on the top of the tank. Blow real hard into the hose. It should be sealed and you should not be able to expel air into the tank. If you do then you got a leak.
I waited until I was having this problem again and measured the depth of gas in the tank. With the bike sitting upright, there is 1.5" of gas in the tank. (I will fill tomorrow and check how much it takes.)

I unhooked the pressure side fuel line and could pretty easily expel air into the tank. It appeared that the pressure side was had the white collar in the picture below. (I also tried on the suction side (blue), but couldn't expel air in that side.)

I'll be buying a manual soon and hope that the line with the hole will be obvious when I open the tank.

 

·
Registered
Joined
·
63 Posts
Discussion Starter #16
Last night I checked the gas level with a rod and it had 1.5" of fuel. This morning I got about a quarter mile away before I ran out of gas. I went home got a gas can put a little in and limped to a gas station where I put in 4.5 gallons.
it looks like the problem is occurring at the same gas level.

The only other option is that i am under filling the tank and that it isn't supposed to access the last inch of gas, but that doesn't sound right.

Hopefully the problem will be evident when i open the tank.
 

·
Premium Member
Joined
·
11,245 Posts
Mark,
The pressure side is on the left side of the bike. return line is on the right.
With that said sounds like yours is OK. The return line is nothing more than a tube hanging loosely in the tank for excess fuel to flow back to the tank.
Blue clamp is the pressure side and should not be able to blow any air into it. The other is OK if you bolw air into it.
 
1 - 17 of 17 Posts
Top