recent drop in mileage - Harley Davidson Forums: Harley Davidson Motorcycle Forum

fishstyx · 06-18-2009, 10:53 PM

i was averaging 180 to 200 miles per tank until the other day when after a fill up my 91 softail( bone stock) would start to sputter at about 95 miles. i switched to my reserve and it pepped right back up. when i got to the gas station i noticed the tank was still half full and took less the 2 gal. to fill up. i started back at 0 on the tripometer and at 92 miles in did the same thing. i tried getting as much as i could so i would switch between on and reserve and got another 50 miles until i was dead on the road within sight of a gas station. went door to door to get a jug and walked to the station and topped off, took about 3 gal. i have the owners manual and parts book but just dont know where to start, is it the petcock, i dont see any real fuel filters. i am a novice wrench but got plenty of tools and a desire to learn. any ideas of where to start or what more info you all need. any help is greatly appreciated, want to get back into the wind but dont want to stop at half the normal distance.

Rock Slide · 06-25-2009, 08:48 PM

I'm digging way back into the burnt memory cells but... There used to be a screen around the end of the petcock, up inside the tank. Maybe you got some tank prep pealing off inside the tank and clogging the screen.

Just a guess...

Ohutchins · 06-26-2009, 11:21 PM

I would definatly start by removing the petcock and cleaning the screen on it.

Blackdog 15 · 06-27-2009, 01:08 AM

Sounds like a venting problem, usually in the cap...if it sputters when you're riding, reach up and loosen the cap, then retighten it...see if it stops the sputter....the early softail had this problem....by opening it, you are releasing the built up vacuum inside letting the fuel flow ...

ARBY · 07-19-2009, 04:56 PM

Are you running an in-line fuel filter by any chance? I was having the same problem a few years back. When the tank got around the half way point the the carb bowl would run empty.

Remeber, gas is gravity fed into the carb. If you don't have a fuel pump some of the in-line filters don't flow fast enough from the pressure of the gas. I ditched the filter and never had the problem again.

Blackdog 15 · 07-19-2009, 04:59 PM

Vent problem....maybe the cap vent

fishstyx · 07-26-2009, 08:48 PM

i pulled the petcock screen and douched that out, it was filthy. i also adjusted the choke and checked to see if the vacum piston in the carb was gummed up. my choke wouldnt stay out on its own and the piston went up and down smoothly. when i put the parts back on and filled the tank the bike started up and idles fine. but when i go to accelerate it feels like the fuel gets cut off. if i accelerate slowly ( cars were beating me off the line) it runs well but i open the throttle anymore then say a quarter turn she sputters and no acceleration till i close the throttle again.

Hogrotten · 07-26-2009, 11:08 PM

Sounds like accelerator pump isn't working now. Take the air claner of and eyeball the throat of the carb to see if you get that initial squirt of fuel when you twist the throttle.

fishstyx · 07-26-2009, 11:41 PM

when i had to the air cleaner off earlier i got the initial squirt and the baffle would open and close fine. i am gonna hit the owners manual and try a few things but any advice i greatly appreciate. thanks guys

fishstyx · 08-01-2009, 11:46 AM

i must have not had the air cleaner seated properly, pulled it off and re-installed and bike is running well again