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Engine Dies And Runs In Spurts


Veteran Member
Sputtering and stalling(Fuel Injection)

Erratic running, surging and a hissing or bubbling in the tank noticed after the pump cycles.

There's been some issues with engines in the fuel injected models sputtering and dying at half a tank of gas for no apparent reason. One cause for this is a fuel line inside the tank that is rubbing on the inside of the tank and wearing a hole in the line. When the tank gets to about 1/2 full, the motor will sputter and stall. This could be the problem but the fuel level isn't a necessary part of the equation here. The engine needs fuel pressure in the area of 50 LBS to operate right and if the line is causing the fuel pressure to bleed off, you will have sporadic running and stalling as a result.

You can try adding gas to the tank and it will usually run better again indicating this problem but a fuel pressure test is the positive diagnostic procedure for this situation.

The fuel pump will have a different sound to it like a hissing or whistling when pressuring up at start up if this problem exists and you may see fuel spraying around inside the tank when the pump is pressurized.

If you remove the fuel pump fuse to diagnose this condition, the engine should start, then stall with the fuel pressure that is in the line normally. With this pin hole in the hose , the engine will not start after removing the fuse because the fuel pressure has bled off. It's another way of verifying this problem.

You can also hear the problem by opening the gas cap and turning on the key.You'll hear the fuel squirting from the line in a hissing sound when the pump is priming. You will also notice more than average priming before starting.

If you are replacing the convoluted tubing with something other than the replacement from HD, the fuel line is 5/16 ID in case anyone is interested.

"Chopper" posted this for removing the pump from the tank that may be helpful...

The trick is pressing down on the fuel pump, it's like a spring loaded latch, once you get that released it will come right out, the first time is the hardest.

Raise canopy slightly to access top fitting (inlet port) at back of fuel pressure regulator. Using a side cutters, cut hose clamp and remove convoluted tube. Exercise caution
to avoid cutting or damaging tube or dropping pieces of cut clamp into fuel tank
A spring-loaded hinge on the fuel pump bracket facilitates removal of the assembly. For best results, press down on top of fuel pump with end of screwdriver, and after raising canopy slightly, rotate on hinge in a counterclockwise direction. When canopy is at a 45° angle to top of fuel tank, carefully pull assembly from left side lobe of fuel tank.

Remove and discard canopy gasket. Verify that sealing devices from screws are not lodged in canopy holes. Remove and discard devices if present

The manual mentions how to remove the assembly, but it's not very clear, If you reach inside and actually push downward on the pump itself, it will then swivel downward which allows it to be removed fairly easily. It makes sense once you have it removed.

The pump, pickup, and fuel sender assembly all can pivot 90-degrees. With it at 90-degrees, the assembly goes in and out with relative ease.

Check the side of the corrugated fuel line for abrasions. They rub on the tank and can wear through causing poor running.
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THANK YOU!!! I pulled my fuel pump last weekend and found my hose looked exactly like the one in the picture above with the holes in it. I think its important to understand that the hose that gets the holes in it is the one that goes from the regulator to the quick disconnect fitting and not the one that goes from the fuel pump to the fuel filter. I went ahead and replaced both and the fuel filter while I was in there.

This solved many problems for me.

First, I have not been happy with the way my bike performed when I ran at low rpms in the lower gears. (Like around town and between stop lights) I have read many post about lugging, chugging, bucking and all that. That's what my bike did at the low rpms. FIXED!

Second, I thought I was going crazy when I thought I felt a miss every so often while scootin down the highway at higher speeds. I kept trying to tell myself that I was just imagining it. In airplanes, they actually have a name for this syndrome. But I wasn't imagining it, it was really missing due to this hole. FIXED!


I have a new problem now that I have fixed this one. I filled the tank once I finished fixing this and have only gone 115 miles but the gauge reads almost empty. I know the manual talks about not bending the float arm, and I don't think I did as I was pretty careful. Then I thought maybe the computer takes a tank to reset because it has been running the other way for a long time. Or, it could be that I need to readjust my TFI now that I have good pressure. Am I on the right track or is there something else that I am not considering.

BTW: If you have not donated to this site yet and you have used one tiny thing from it to fix a problem on your bike, I URGE you to please do it. It only takes a second and well worth it! This issue alone saved me hundreds of dollars and I didn't have to deal with the stealer except to buy the parts.

update---replaced both fuel lines and fuel filter. problem solved. the dealer provided a fuel filter "kit" consisting of fuel filter with line attached and clips. the new line was shorter than the original. also, the other line was shorter too. seems the factory knew of the problem and corrected it with new parts but will not own up to it. if i had it to do over again, i would have the dealer do the work. turned out to be a chore!

thanks for your help. this is a great site. and...donation on the way.
If you are replacing the convoluted tubing with something other than the replacement from HD, the fuel line is 5/16 ID in case anyone is interested.

fuel line chaffed inside my tank. local dealer seemed to pretend they never heard of it.
imagine that, they had a shorter line instock. ride safe!
Island 65
If you are replacing the convoluted tubing with something other than the replacement from HD, the fuel line is 5/16 ID in case anyone is interested.

I know a tech in AZ. that substituted the hose because they did not have one in stock and the customer was traveling. Well it worked for about 50 miles then collapsed with the pressure, they had to go pick him up on the road. Should have had the correct part overnighted. So if you do substituted keep pressure from fuel filter to pump in mind.
After about the third time I had to pull all that stuff out of the tank because one or the other of those cheap plastic tubes that HD uses for this application had worn pinholes against the inside of the tank somewhere, I replaced them with some high pressure reinforced fuel injector hose (from the autoparts store). Tough stuff, and WAY overkill! But if I have to go back into the tank for something, it WON'T be because the hoses have worn through!

Good deal TQ using good tip regarding that silly fuel injection hose. Only reasons for using convoluted plastic fuel line is bend radius and cost...your solution is the best compromise for those two conditions. :s
TQ, I hope that the high pressure reinforced fuel injector hose that you used for replacement from the auto parts store, was of the submersible type. There is a big difference.

Ordinary fuel injection line hose is designed to handle fuel on the inside only.
Intank submersible fuel injection hose can be exposed to gas on the inside and outside.

If you have used high pressure fuel injection lines for in tank use, it will eventually burst because the exterior of the hose cannot be exposed to gas. The chemicals in gas, diesel, and other blends will break down the hose to point where the pump cannot flow anymore or hose may burst.

Not the cheapest, it may run $12 to $16 per foot