At High speeds.........

[SpidyJ]

........she breaks up if I have less than 1/2 tank?!?!  Say over 80 or 90.

I think I'll rebuild my stock petcock and put it back in.....I suspect the pingel.......whaddaya think?

[Michvalk]

Crap in the tank? Restricted fuel flow. Maybe a kink in the fuel line, or just a little too long causing a droop between the petcock and the carbs? Partially plugged or kinked vent line from the back of the tank?  Just a few ideas

[Toledo Mark]

I had that problem after I added a quick release fuel line.  Took it off and back to normal.

[R J]

Crap in the tank? Restricted fuel flow. Maybe a kink in the fuel line, or just a little too long causing a droop between the petcock and the carbs? Partially plugged or kinked vent line from the back of the tank?  Just a few ideas

I think Michvalk has nailed about all the items to fault.    My guess would be the gas line has a low spot in it.     Remember, these are gravity like the old Model A.

When I was in the service, I had a Model a in San Fran.   Some of the streets (hills) if I wanted to go up to the top, I had to back up just to get fuel to flow to the car.

[SpidyJ]

...I don't know fellas, why only when the tank is 1/2 full or less. Never on a full tank!

[Bone]

Weight of the gas. Half of a tank applies half as much pressure on the gas. Restriction in the line/ carb. would need a higher pressure to flow the liquid.

The screen in the gas tank could be partially plugged.

[Hoser]

The vent tube off the bottom of the tank is probly pinched part way shut.  Did you remove the tank lately?  Hoser

[SpidyJ]

The vent tube off the bottom of the tank is probly pinched part way shut.  Did you remove the tank lately?  Hoser

...when I changed petcocks......I'll check this first.  Maybe I won't have to take the tank off until I rebuild the petcock..Thanks.

[MP]

You said you put on a fuel filter.  Some of them cause this exact problem.  Try taking it off, and see if the problem goes away.

MP

[SpidyJ]

You said you put on a fuel filter.  Some of them cause this exact problem.  Try taking it off, and see if the problem goes away.

No...no filter.  Installed a Dan Marc and a Vacuum Pingel.  After that problems.........but only when <1/2 tank and at high demand like > 80 mph.

[John Schmidt]

Bone hit the mark along with Michvalk & RJ. With the addition of the Dan Marc, people often create too long a line from the petcock to the tee. That causes a low spot in the line and under pressure/weight of the fuel with a full tank, no problem. As the tank empties, less weight hence less pressure. Your fuel line from the petcock to the tee must run downhill all the way or you will get exactly what you describe. Before removing the tank, see if you can prop up that area a bit then take it for a ride, see if the symptoms lessen. It often will show up only at high speed/wide open throttle since the fuel demand is greater then.

[Farther]

Installed a Dan Marc and a Vacuum Pingel.  After that problems.........but only when <1/2 tank and at high demand like > 80 mph.

  Isn't there lower available vacuum at higher RPMs?  If so there might not be enough vacuum to keep your new Pringle open.

[SpidyJ]

Installed a Dan Marc and a Vacuum Pingel.  After that problems.........but only when <1/2 tank and at high demand like > 80 mph.

  Isn't there lower available vacuum at higher RPMs?  If so there might not be enough vacuum to keep your new Pringle open.

...same exact thought.  I will get to the bottom of this!

[fordmano]

Crap in the tank? Restricted fuel flow. Maybe a kink in the fuel line, or just a little too long causing a droop between the petcock and the carbs? Partially plugged or kinked vent line from the back of the tank?  Just a few ideas

I think Michvalk has nailed about all the items to fault.    My guess would be the gas line has a low spot in it.     Remember, these are gravity like the old Model A.

When I was in the service, I had a Model a in San Fran.   Some of the streets (hills) if I wanted to go up to the top, I had to back up just to get fuel to flow to the car.

Never had the problem but just an idea (Although a fairly expensive solution) Manual Pingel & Belly Tank for the "WIN" . Fuel pump will remove the possibility of gravity effected fuel starvation.... Also prevents future posibility of HydroLock, and greatly extends available range of travel.

[SpidyJ]

What's  belly tank?

[fordmano]

Oh boy, now you opened up the discussion.

Here is the link for the source.
http://rmworksinc.com/

Basically it is a 2.5 or 3 Gallon tank that mounts below the swing arm and it has an electric fuel pump attached that way the fuel is at a very low pressure is forced up to the carbs.

Remember search can be your friend here and on the web.
I just rolled into the driveway and headed to bed now so if you can't find adequate answers on this forum or elsewhere there are lots of smart folk that will chine in shortly.

The biggest problem is the tank is expensive its worth the money in my opinion BUT at $450.xx + shipped a lot if folks think the benifits are not inline with the price.


Once it is installed and I am sure you have the skill level as most would have considering I was able to properly install mine, you would have no problem installing it yourself, a slate set of hand during installation is a GREAT idea from my experience. It mounts to the kickstand crossmember and the exhuast hangers. I just rolled down the highway at well over 110 mph and my belly tank supplied plenty of fuel for that level of service.

I am not in any way affiliated or related to the creator/designer/manufacturer/seller of the belly tank.

Search read learn enjoy.

Good night I am headed to dream land.
I will check back this afternoon and see how this thread is progressing.

[fordmano]

Oh yeah, with having an I/S and adding the standard 3 gallon Belly Tank that give me right at 9.9gallons of fuel on-board. Now I can run around almost 300 miles before really seriously worrying about finding a gas station. So I can just about drive to work and back all week on one fill up.

[Michvalk]

I had the same problem when the intake the petcock was hooked to started leaking. I found it after finding a oily residue at the base of the intake. New o-rings in the intakes, and not only fixed the petcock, but, it idled smoother as well

[SpidyJ]

Anybody try the redeye franken filter setup combined with a Dan Marc?

[SpidyJ]

Finally cleared up/warmed up so I rode into work today.   90-100 mph for >5 minutes with a full tank.
Not one hiccup.......this is definitely a fuel flow problem from a belly or something in the line.

Hope I don't have to remove the Dan Marc.

Still waiting for the Petcock rebuild parts and screen from Mother Honda.

[John Schmidt]

Finally cleared up/warmed up so I rode into work today.   90-100 mph for >5 minutes with a full tank.
Not one hiccup.......this is definitely a fuel flow problem from a belly or something in the line.

Hope I don't have to remove the Dan Marc.

Still waiting for the Petcock rebuild parts and screen from Mother Honda.

Spidy, I've had the DanMarc and an inline fuel filter in place for 5-6 yrs. with absolutely no problem. You just have to make certain everything is flowing downhill from the petcock. Pure and simple. This coming Spring I'll be pulling the tank to clean the air filter and will replace the fuel filter for the first time since it was first installed. That, along with pulling the rear end apart, will be part of my getting the bike ready for traveling again.