help.help.help very poor gas mileage.about 15 MPG

[larswlvs]

Can some one tell me what is happening. the bike run great,carbs are in sync.new spark plugs ( the old ones looked OK, no sign of rich fouling ) Good spark on all plugs.  no sign of gas dripping or smelling of gas when running in neutral or turned off,air filter looks OK . Could the gas be going into my oil ? OIL does not smell like gas but it was above the full mark . I run out of gas at 75 miles ?

[Valker]

One tank or repeatedly?

[Steel cowboy]

 Does the oil look thin or watery how much about the full Mark is it ?

[..]

My previous Valk did the same. Petcock diaphragm failure was to blame.

Someone will chime in with a more tech explanation I'm sure.

[Valkpilot]

My previous Valk did the same. Petcock diaphragm failure was to blame.

Someone will chime in with a more tech explanation I'm sure.

+1

[old2soon]

My previous Valk did the same. Petcock diaphragm failure was to blame.

Someone will chime in with a more tech explanation I'm sure.

+1

               +2

[bassman]

What tire pressure are you running?  At least 40# front and
42# rear (not a car tire)?

[Moonshot_1]

Can some one tell me what is happening. the bike run great,carbs are in sync.new spark plugs ( the old ones looked OK, no sign of rich fouling ) Good spark on all plugs.  no sign of gas dripping or smelling of gas when running in neutral or turned off,air filter looks OK . Could the gas be going into my oil ? OIL does not smell like gas but it was above the full mark . I run out of gas at 75 miles ?

Would we be correct in assuming that by "I run out of gas at 75 miles" you mean you have to switch to the reserve line and not that you are actually completely out of gas.

If that is correct, have  you had any work done on the fuel lines? I seem to recall that if a fuel filter is installed that the line could be above the petcock and lead to a situation that would have limited your regular fuel line capacity but increased your reserve capacity.

I would fill the bike while sitting on it. Fill it pretty full. Go for a ride. When you switch to reserve actually open the tank and see how much fuel actually remains. If it still looks fairly full or even half full, you got a fuel line issue. If it seems that it should be where it should be at reserve, then the search continues.

The tell for me is that you say the bike runs great. If the bike runs great then it is unlikely that gas is getting into the oil.

Of course this is all a guess by someone who doesn't wrench on bikes. But I do read the boards here and they are better than a Holiday Inn Express.

[gordonv]

When you run out of fuel, how much do you add to the tank to fill it back up?

[Bagger John - #3785]

How do your plugs look?

Check all 6 cylinders.

[Fazer]

I am in agreement with the petcock suggestion.  There is a link in the shop forum that shows how to rebuild with a "cover set."  Cost is minimal and it's easy to do.  Just watch which position you are in when removing the selector switch--takes a long screwdriver (Phillips of JIS).  When it's time to re-install, you will want it in the same location.  You will have to remove the tank to get to your petcock, not terribly difficult.  (If this is unnecessary, someone will chime in.)  Search the forum on methods.

Lastly, check you vacuum hoses running to the intakes.  And the intake tubes themselves.  There is an excellent thread by Valkpilot that is just above your thread--talks all about vacuum leaks.

I see you are in Akron.  I grew up in Akron (Stow) and moved to Cincinnati about 30 years ago.  I miss Akron, but don't regret relocating here.

Greg

[Chrisj CMA]

The big question is, when you say it's out of gas at 75 miles is it really?  Is it out of gas or hitting reserve prematurely?  Next time it goes to reserve at 75 miles fill it up. If it doesn't take four gallons then you weren't really out. I too suspect a petcock or fuel line routing issue.

[larswlvs]

One tank or repeatedly?

    two tanks

[larswlvs]

not sure how to reply separately to each of you. it has done this on two tanks of gas, and the second tank i was completely out of gas.the first tie i was near a station so i do not know how much gas was actually in the tank, but it took 11 dollars to fill it. On the oil , it was about a half a pint above the full mark and did not smell much like gas. i took the tank off and checked the tank screen , it was OK the air filter is also OK the plugs look normal. my petcock has been converted to only have normal reserve and off not using a vacuum hose. i use a danmark electric shut off to shut off the gas. The bike runs great other the the gas usage.i do not smell gas or see any leaks? i will cheek the tire pressure but riding the bike , the bike not feel low . IM STUMPED

[gordonv]

i was near a station so i do not know how much gas was actually in the tank, but it took 11 dollars to fill it.

OK, but how much full is $11? At $3/gal, I figure you put less than 4 gal in your tank. The tourer has a 5.3 gal tank, so you seem to be around the reserve mark. You can't be out of gas, no mater how I calculate this.

I think you have a pinch vent hose. Have you had the tank off recently?

[larswlvs]

gas is and was below 2.30 a gal here, it fluctuates almost daily . i did have the tank the other day but before that not recently and i was getting normal gas mileage until the other day. i put new plugs in, maybe i should pull them and recheck them and also do a compression check?

[Bone]

$11.00 / 2.30 = 4.78 gallons
75 miles /4.78gallons =15.69 mpg

I've got 15 mpg before with my 98 Tourer

[Bagger John - #3785]

Checked the air filter element recently?

[Dale_K]

Just guessing - could a brake be dragging?

Another idea, after a ride immediately put a IR thermometer on the pipes to see if any are different than the rest. 

An even more far fetched idea, do a compression test.

Maybe timing jumped a tooth.

[Moonshot_1]

not sure how to reply separately to each of you. it has done this on two tanks of gas, and the second tank i was completely out of gas.the first tie i was near a station so i do not know how much gas was actually in the tank, but it took 11 dollars to fill it. On the oil , it was about a half a pint above the full mark and did not smell much like gas. i took the tank off and checked the tank screen , it was OK the air filter is also OK the plugs look normal. my petcock has been converted to only have normal reserve and off not using a vacuum hose. i use a danmark electric shut off to shut off the gas. The bike runs great other the the gas usage.i do not smell gas or see any leaks? i will cheek the tire pressure but riding the bike , the bike not feel low . IM STUMPED

Let's clear up a few things here.

When you say you were "completely out of gas" does this mean you depleted the reserve as well?
Or does this mean you had to go to reserve?

Do you have an inline fuel filter installed? As I understand it , this could cause issues with the gravity flow of the fuel if the fuel line is not the proper length. The line would ride higher than the valve or gas level in tank.

Next time you fill, get the number of gallons you put into the tank.

Maybe this has been stated but do you have a standard, tourer, or interstate model?

Are you experiencing any oddities, weird sounds, or poor performance?

Is this a recent situation? If so, what, if anything, did you have done to the bike prior to this? Even minor stuff.

These bike usually will get about up to the upper 30's (mpg).

My thought is still you have a fuel line issue with problem being an excess of fuel line cutting off the flow with the fuel line being above the fuel valve. When the fuel level in the tank reaches the same level of the highest point of the fuel line the flow stops. Gravity no longer is effective in this gravity fed system.
The reason to narrow this down to this possibility is that you say the bike is performing great. I would think that such a fuel discrepancy would otherwise have an obvious and adverse effect on performance. So the issue isn't performance related.
As to a gas leak, this would be a rather significant gas leak. You would be losing about 1/2 a tank per fill assuming a 35 mpg typical mileage for a Valk. You are getting 15 mpg. You'd smell that I would think.

[Donald]

 Sounds like we have too many cooks in the kitchen,  poor mileage and a Valkyrie usually comes down to , two possibilities.
 #1  Vacuum lines cracked and leaking (air)
 #2  Choke cable holding chokes closed. (check it at front of intake runner)

  #2a,  added new fuel line with extra length to install tank easier and blew the trickle down effect,(gravity)

My 2003 Standard was down to 20 mpg due to vacuum lines and old age, with a valve set, carb overhaul and new lines, she is now 38-40 mpg, what a difference !!!

[oldsmokey]

Just in response to oil level over the full mark. Was it at or below previously? How much over full? Take the dipstick with oil on it to a safe area and try to light it up. Oil will not readily burn, diluted with gas it will, all dependent how much dilution there is.