Howdy friends,

My Dad and I fixed up his 1979 Shovelhead FXS last summer, and was in tip top shape. He says that he has been starting it up every once and a while since then to keep liquids circulating.

In any case, I went to take it for a ride today and it was struggling to run without the choke and a healthy bit of throttle. After letting it run for a good long while, it finally got to the point where it could idle on its own without choke, but it sounded really weak AND I noticed something a little worrisome--

One of the pipes was spitting out light colored smoke and thin liquid (I first thought oil, but now believe to be fuel) was coming out. Only on the one pipe.

The bike would bog down and die under any kind of load until we'd had it idling for a good 15 minutes. Then when I took it out to the street and fully accelerated, it began to backfire like a machine gun--with bursts of power on each backfire.

I'm suspecting that fuel in one of the cylinders isn't being properly ignited, but wondering what you all think. I'm not an experienced Harley guy. My Dad tells me that he tipped it over in the garage while trying to move it earlier in he year... and I'm wondering if that may have led to an exhaust leak & improper mixture. What do y'all think?

Thanks for your help.

 

Sounds like it's flooding. Since he tipped it over, the float my have gotten stuck or trash in the bottom of the bowl got into the seat. There are two routes you can take. Take the carb bowl off and clean out. Recheck the float level and put it back together. You can also block off the fuel line from the tank and let it run til the fuel is gone. This sometimes will suck the trash out of the needle/float seat. I've had success with either way. Today's gas goes bad quikly. Add a little Stabil or fuel stabilizer when you put it up for the winter. Your dad or you needs to ride that bike !

 

I agree with Vanmor...todays Gas is absolutely **** and don't last a week...Period, You will do a Proper cleaning on that Carb or it will Never work OK...If yer just gonna let mit sit again...you are wasting your time, just like idling it excessively...takes more Life Out of it than you are putting in...Just makin yerself feel better...

 

To be fair, the winters here in the Mid-South are pretty mild. It's rare that we get snow and ice. This winter was really mild. Even so, a lot of riders around here didn't get their bikes out. Last month, there were a lot of folks crying the blues. They left their bikes outside (although they were covered) and none of them are running worth a damn. Especially the new bikes. If you think a carb hates bad gas, try fuel injection ! My neighbor and his Vulcan can tell you all about it.

 

Would a sticking float cause only one of the cylinders to flood? It's only the front cylinder that is spitting gas / smoking.

 

1. Verify your plug is getting a spark. If not... replace the plug, wire, or coil. Whichever has failed...

2. Check your points. Make sure the plate is advanced properly, and the gap is set.

I would do both of those before pulling the carb. Those are 5 minute jobs, the carb could take all day.

And, because the engine has been flooded... After you get it running, change the oil.

 

One other theory is the carb squirter from accelerator pump might be twisted and shooting most of the fuel into one side of your intake. Pull the aircleaner and twist the throttle with the bike off and bowl full of fuel. See where the shot of fuel goes. If not at the center of the intake, you can twist the tube to change direction.

 

Change the plugs first off then don't flood it next time you guys try to start the poor thing.

 

Thanks for all of the advice, friends.

My suspicion was that fuel was only spitting out of one pipe because that cylinder wasn't getting ignition, so we pulled both plugs, and sure enough--the front cylinder (which was flooding / backfiring) had a blackened, fouled up plug (from running too ruch, not deposited with oil) and the other looked totally fine.

With a new set of plugs it runs great now--but I'm sure the new plug is going to be fouled soon by whatever caused the last one to go bad. My question is--could a stuck float bowl foul only one of the plugs? Seems to me that it's an ignition issue instead but I guess there's a chance that the fuel all drains into one cylinder?

Sounds like I need to check the points---never worked with points before.

Any additional advice appreciated.

 

Drag Pipes??