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Discussion Starter #1
I've had a very strange problem ever since leaving Atlanta on Weds. Here's what is happening:

If I run at 70 mph+ for 1 to 1-1/2 hours, the bike acts like it is running out of gas. It sputters and then tries to die. I'll downshift to keep it running. Once I slow down the problem seems to go away. This happens on every tank of gas.

The HD tech, here in Wichita, thinks it may be problem with the float or diaphram.

What do you think? I'm tempted to wait until I get back to Atl. before doing anything. Bad idea or not?

2000 FLHT (Carb.)

Thanks.
 

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I think the tech is wrong unless it is a really marginal failure. If you have a problem with the diaphragm in the CV the bike will have no power at any time in any gear and if it were the float it would likely act any which way it wanted whenever it wanted.

I think it is either one of three things, a problem with the vent in the gas cap (partially open or take off the cap and see if it goes away), a problem with the vacuum operated petcock (if it breaks you can take it apart and put the spring on the other side effectively making it into a manual petcock) or some dirt in the tank partially blocking the screen (no biggie, if it gets you stuck cut it away with a knife to limp home).


If this is not it, and the bike is pushing a lot of wind and the ambient temperature is on the high side it might be vapor locking. It is rare but if someone took the plastic sheet off the fuel line, it happens.

If you think it might be vapor locking put a cup of Marvel Mistery Oil in with a tank of gas, if you think something might be dirty after you try the gas cap thing you may try a can of a strong fuel system cleaner like Berryman or Techroline.

Up to you, but it doesn't sound real serious.
 

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Fuel problems

On all of my engine rebuilds that I do I recommend that you get rid of the vacuum operated petcock, and switch to a manual one and run the fuel line to the back side of the rear cyl. and up to the carb. Also like HIPPO said check for the gas tank venting.
 

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Discussion Starter #4
Because I had changed routes on the way home, I wasn't able to maintain 70+ mph long enough for the problem to show up all that often. In fact, it happened only once. During that time, I attempted to open the gas cap, but I had slowed so much while doing that, that I really couldn't tell if it made a difference or not. Since it doesn't do it on the short stop/go runs, I may never know if I've got it fixed or not. I'll try the Marvel Mystery Oil and check the petcock.
 
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