Yesterday I was riding out to work and noticed that under medium acceleration my bike studdered twice on the way up to 50mph. I also had a backfire through the gears. The backfire seems to happen all the time, but this is the first time I have felt a loss of power under accel. Any ideas?

 

The weather has gotten colder and the fuel mixture is now lean enough to begin to bother the engine.

 

Bump.

I'm having this issue on my 1996 FLHR as well. It will idle fine, when I give it gas to go, it would 'cough/sneeze' / misfire out the carb. Sometimes it dosen't even misfire, it just hesitates for a second then it takes off.

If I drag though the gears, it doesn't happen but if I were to be at the lowest speed for a particular gear (low RPM too) then it happens. Once I bring the revs up, the sputtering goes away.

The thing is, it doesn't happen all the time. Only occasionally and when the bike is properly warmed up.. have never noticed it happen when it's cold.

Bike has Wiseco 80" 10:1 high comp pistons. All else is stock.

I have changed my carb, plugs, ignition module, plug wires, coil. Cam sensor has under 10,000 miles.

Now for the wierd part. If I let the bike sit for about 5 days, it would run fine for about a week then start to misfire. But, if I'm riding today, and it misfires, tomorrow, when I ride the bike again in the morning, by the afternoon, the misfiring would start.

One of my Crane lifters would bleed down when parked and would tap like crazy when warming up but once the oil's in them, they're silent. Could these be the problem? I doubt so.

Any experiences?