I have a ’91 Springer with an 80” EVO, Stock carb.

I ride it to work and everything is great. Starts right up in the morning, runs great on the way in. After work, when it’s time to leave I go to start it and it doesn’t want to start. Backfires and coughs and sputters. When I finally get it started it runs rough and seems to lack power. No enricher needed to start it when the issue is not occurring, petcock is in the on position. I have, when it is running crappy, changed it over to Reserve in case there is some crap in the tank having an impact. No change.

If I let it sit for a couple days, I can fire it right up and I can repeat the process above.

Makes absolutely no sense. It’s not hot when I get ready to leave work, it’s been sitting for 9+ hours. It hasn’t moved since I parked it after arriving at work.

Ideas… Thoughts??

 

Do you shut the petcock off during the day? Might be a stuck float dumping gas into the cyls and fouling the plugs. That would account for not needing the choke to fire it up.,

 

I don't normally turn the fuel off. Though, I've thought about doing that to see if it has any impact. Just haven't tested that yet.

 

That carb is 20 years old, and there is a significant likelihood that the float needle may be seeping a bit. With the gas left on, this can cause the engine to flood over time.

Try shutting the gas off during the day (you SHOULD be doing this anyway), and see if that helps. If it does, a carb rebuild kit may be in your future.

 

I'll give that a try and see if leaving the fuel off during the day solves the issue. Though, even with the fuel on, after a couple of days sitting in the garage, the bike will fire and run just fine after running like crap.

Though, I should probably should have the carb rebuilt anyway.

 

Try draining the gas tank and cleaning the filter on the tap as well. Do that in a very well ventilated area!

I had an air-cooled BMW twin for many years and about once a year I got into the habit of cleaning both float chambers. They accumulated a little water, from condensation inside the fuel tank, plus other muck, which affected the running.

 

I forgot that, but then, I clean the float bowl as part of my 5K service.

 

Will the bike start up the next day for work? What temp. is it when you leave for work and what is it when you go home? Did this just start to happen one day? Anyone at work hate you? Just kidding. How far is it to work? Do you ride it on the weekend? Little more info please.

 

It's prolly a keihn carb. 38 mm. Pull it off & get a 40 mm mckuni or cv carb. you will have more power & a quick start.

 

Years ago the wifes Sporty was acting like it was having carb issues. Long story short.....PLUG WIRES !!!!! Wire inside had turned to powder almost. Good Luck