Odd fuel starvation problem

[sdv003]

I'm having an odd fuel starvation problem.  Only happens when out on the open road.  My in town commuting doesn't experience it.  About 60 miles into a full tank, it starts to starve.  That's about 2 gallons used with the MPG I get.  I switch to reserve (I have a pingle) and I can get another 30 miles (and maybe more, I've not tried more than 30).  Sure seems to me to be low flow in the "on" position.

I've checked all the usual suspects:
- DanMarc appears to be working fine
- Fuel line is running downhill with no low spots. 
- No visible rust in the tank.  It gets ridden regularly, so I turn over the gas often.
- Vent line is clear, and it acts the same if I run with the vent line disconnected

A few questions:
- Is it possible to clog the pingle in a way that reserve works fine but "on" has low flow rates?
- Anything else I should check?

My next test is to see if I can empty the tank in reserve without premature starvation.  Then I will pull the tank and clean the pingle.  Any thoughts are appreciated.

[Valker]

Still sounds like a plugged vent line to me. Try putting a coffee stirrer straw in the gas cap when closing it. Maybe just stop, pop the gas cap, close it and see if it runs fine again for a while.

[Ricky-D]

My suggestion would be to remove the DanMarc and see if that solves your problem.

The DanMarcs have been known to restrict fuel flow in many instances.

***

[h13man]

Still sounds like a plugged vent line to me. Try putting a coffee stirrer straw in the gas cap when closing it. Maybe just stop, pop the gas cap, close it and see if it runs fine again for a while.

Good idea to quickly resolve venting issue. As for a Pingle, mine had been on a bike that had only 11,000 put on it 14 yrs. and now 45,000 and the Pingle works fine especially when you forget to turn back on.  Outside the Dan Marc, I would look into excessive crud build up in the tank. A extreme vacuum leak to carb circuit? but I would think one would hear it but...

Had similar issue on my 1100 Spirit (2 yr.old) after 2 times the dealer found it would heat up a fuel line and it would collapse. The bike would also vapor lock on extreme hot days sitting parked 45 mins. or more so  thus boiling the fuel line.

[Foozle]

12-01

I had very similar symptoms on a 1997 Tourer - and suspected my placement of the Dan-Marc fuel valve was causing a slight dip in the fuel line once the engine heated up.  (Preemptively, I had installed a brand new OEM petcock).  After sitting several minutes, the bike would start after switching to reserve - although, in retrospect, the two may have been unrelated.

On closer inspection of the Dan-Marc, however, I found the contact wire leading to a relay near the battery was rubbing against the frame and had exposed a small patch of bare wire - creating (I suspect) the possibility of an intermittent "disruption."

I decided not to reinstall the Dan-Marc (I've since trained myself to religiously turn off the fuel petcock), changed all the fuel lines back to exact OEM specs (length, etc.), and haven't had a problem since.

Unfortunately, given this recourse, I wasn't able to definitively identify the specific issue with the Dan-Marc, but removing it from the fuel flow seemed to be the ticket - odd, because so many here have run one for years without issue.

My ham-handedness in the installation likely played a role.

As always, YMMV.

Terry

[The emperor has no clothes]

12-01

I had very similar symptoms on a 1997 Tourer - and suspected my placement of the Dan-Marc fuel valve was causing a slight dip in the fuel line once the engine heated up.  (Preemptively, I had installed a brand new OEM petcock).  After sitting several minutes, the bike would start after switching to reserve - although, in retrospect, the two may have been unrelated.

On closer inspection of the Dan-Marc, however, I found the contact wire leading to a relay near the battery was rubbing against the frame and had exposed a small patch of bare wire - creating (I suspect) the possibility of an intermittent "disruption."

I decided not to reinstall the Dan-Marc (I've since trained myself to religiously turn off the fuel petcock), changed all the fuel lines back to exact OEM specs (length, etc.), and haven't had a problem since.

Unfortunately, given this recourse, I wasn't able to definitively identify the specific issue with the Dan-Marc, but removing it from the fuel flow seemed to be the ticket - odd, because so many here have run one for years without issue.

My ham-handedness in the installation likely played a role.

As always, YMMV.

Terry

Any electric device that has a shorted wire is going to be a problem.




Sam, as to your fuel problem. I've had 2 problems in the past that had similar symptoms as yours. One was a fuel line just an inch too long. When it got warm it would collapse just enough to inhibit flow a little. The other was an askew chrome engine hanger that was binding on the fuel selector slightly. I think the little ball valve was not opening fully.

[Punisher]

Can you blow back through the vent line and separately through the vent tube into the tank?

Three problems I've seen:

  1. A dirt dauber had gone up inside the vent line about 4-5 inches in and plugged it with mud for about 2 inches.   Not obvious from looking in either end.

  2. Vent line got blocked within tank by some crud.   Hook a vacuum line to the vent tube and see if you can blow through it.   If not use a air nozzle on a compressor and blow air back through it with some reasonable pressure.

  3. A failing OEM petcock.  I converted it to a manual on the side of the road at near 10k feet on top of Beartooth Pass.   Since you're using a Pingle I would not expect it to have that problem.   Is this the manual Pingle (what model?) that most people are using on a Valkyrie?

The first two caused the exact symptoms you describe.   Switching to reserve would temporarily over come the vacuum being built up inside the tank as fuel flowed.    Switching to reserve did not improve the situation for the Petcock.

[MarkT]

I had starvation issues pulling my Timeout camper with my 97 from Colorado to Morgantown Inzane, about 1500 miles.  I had modified the fuel system extensively with a custom belly tank install.  Figured my mileage with each tank - at times it became severe.  Worst was 17mpg and that's an average of the tank - momentary draw say uphills and at higher speeds would have been worse.  Average for the trip was about 24mpg.  I found starvation happened at higher speeds, uphill on the slab, and in the afternoon when it was hot.  Also when I let the level in the main tank get below 1/2 full.  (My install uses gravity feed from the main while the BT is a super-reserve that replenishes it when I activate the pump and valves.)  At that time I had the smaller Dan-Marc.  Upon return I made some changes to the fuel system and the problem was gone.  Those changes were, bigger Dan-Marc w/ 1/4" orifice, ensured the fuel line was correct length and with no dips or rises (including changing the OEM plastic T to a brass one with screw-in fittings so I could put the Dan-Marc right next to the T - that is, w/o barb fittings betwen them. This allowed more hose flex for easier connection to the petcock while keeping the hose straight.) Removed a fuel filter in the gravity feed line.  Replaced the POS OEM petcοck with a forward-feed Pingel.  And added a lever extension to make it findable by feel. The points to take from my experience is heat can be a factor (given your location), lowering engine power requiring higher throttle settings and more fuel demand when your delivery is already marginal.  Also, the engine can be very thirsty under high demand conditions, any bottleneck can cause starvation.  Make sure the entire fuel delivery path is all optimal, look for bottlenecks.  You can also insert a penny under the fuel filler seal to eliminate vent problems when diagnosing - or leave it there, I did that for years with Deerslayer.  Can make it leak if you drop the bike with a full tank, though.  I doubt your problem is caused by your Pingel.

My fuel system is described extensively here, if you're interested.  http://www.valkyrieforum.com/bbs/index.php/topic,84264.0.html

[sdv003]

Been a while (lousy December), but I finally got a bit of time to investigate.

- Vent line is verified clear.  Tank vent is verified clear.

Next is to pull the tank and verify pingle (manual, no vacuum shutoff) is in good working order.  Then I pull the airbox and investigate the danmarc and fuel line.

[Tfrank59]

I don’t know if this will help but it’s really easy to do, back in summer I had a similar fuel starvation problem and I thought it was the petcock but it wasn’t turned out to be I needed to drain the float bowls on all six carbs because there was some trash blocking inside and that was the fix. It’s the kind of thing you do maybe if you’re going to put it into winter storage or what but I got that idea from somebody and again it’s really easy to do you just get a screwdriver and drain the float bowls and see if that helps.

[sdv003]

Turns out it was the solenoid.  I must have been getting better gas mileage when I installed it, so I didnt have the problem.  I guess either do without or use a solenoid with a larger orifice.