10'FXDB, 24k, stock motor, stage 1. Not as much power and exhaust is for sure nowhere near the volume it once was. This happened to me once before. I found a crack in a plug wire so I changed it and voila, back to normal, including the exhaust was loud once again. Two weeks ago, I noticed the loss of power and exhaust was noticeably quieter once again. In order, I have changed plugs, wires, still no dice. This time I even changed the coil.. no difference. The guys I ride with daily, asked me why the bike was suddenly quiet, so it's not just me. BUT.. it runs "smoother" . It used to feel sort of like hitting the power band a two stroke. Consistent power once I got on it. Now it is more gradual and smoother through the range, but anemic feeling. Not sure what to do. No backfire, sputtering, hesitation or weird sounds. The only symptoms are not as much power and quieter exhaust. I did not change anything since running fine and running "odd". It used to be a beast, hard throttle my feet would come off the pegs. Now, i'm begging it for more and it's just not there like it used to be. I have looked it over several time and do not notice anything out of the ordinary.

Any ideas of where to look next?

 

Maybe a baffle or something loose in the exhaust causing a restriction? Might be worth the time to pull the exhaust off, or at least see if you can shine a light up the pipes enough to see anything.

Also, have you checked to see if it set any codes in the ECM?

 

I did check the pipes (BCT monster baffles) to make sure both were putting out exhaust and they are good to go. Baffles are tight in there. Smell like normal exhaust, no excessive unburnt fuel odor or anything. No codes. I do have the FP3 installed, but no tunes installed. I use it for the gauges and engine diagnostics. Oddly enough, when I do install a tune, it runs EXACTLY like it does right now, that's why i dont use it as a tuner. V&H had no excuse as to why when I installed their tune or used the crap auto tune, the bike would run like I lost 50 HP. I tried flashing a tune, running it and then flashing back to stock, with no change.

 

Still nothing on this.. Everything so far has checked out, baffles are tight, nothing stuck in the pipe, no codes. Been riding it since and there has been no change, exhaust is still quiet and the power it once had, is gone. It still runs and rides ok but that hard power feeling and loud rumble just isn't there. I'm at the point where I don't enjoy riding because the bike feels so mush less of it's former self and I can't shake the feeling that something is wrong and I just can't afford to start throwing money at it. Like I said, this has happened in the past on two occasions, 1. When i had a cracked plug wire.. replaced and all was good and 2. When I install a tune from my FP3. Once the tune was installed, I lost almost all power on the lower end rpm but gained some in the high RPM, It was smoother and the exhaust surely went as quiet as it is now. For that reason I left the tune to stock and just used the gauges on the FP3. I wonder now, if somehow I lost my stock tune? I updated the app sometime around when this happened and it gave me a weird "ECM doesn't match error". I clicked cancel and started the update over and it was successful. I might have to contact V&H and see what they can do because it feels like my stock tune is the same as their canned tune for my options.

 

I have the exact same thing going on. 04 fxd superglide, carbureted.

3 days ago it started running more like an import cruiser.
I made no adjustments for weeks.

The power loss is subtle, and mainly only noticable because of the sound. it's actually an enjoyable ride. If I knew for certain it was a harmless thing, I might prefer it like it is now.

I did plugs and wires about a month ago. Double checked the gaps. I also took the bowl off the carb (s&s super shorty) and cleaned everything about 2 months ago.

The day before it started running this way, it failed to start, and I had to get a jump. So maybe that could have kicked off an electrical problem. But it's definitely getting spark and seems to be in good time.

Also it's idling a bit lower, and it did have a slight stumbling miss at idle, that now seems to have cleared up.

Its smooth as butter.

 

I realize the Dynas oil reservoir is below crankcase level, I own two. Have you checked your oil level lately. Is your oil pump not scavenging correctly and now your crankcase sumped. Oil in the crankcase and the flywheels working against oil in the crankcase. Something to check on.

 

I will definitely look into it. The levels are definitely good.

 

are you sure it is firing on both cylinders? have you checked the compression, sometimes starting from the basics is the best way to start.

 

I had considered that, but wouldn't it be running horribly on one cylinder? Fumes and backfires?

The internet says this bike has a 0-60 time of around 5.5 seconds. Although I haven't put a stop watch on it, it's running real close to that. I would think that one cylinder might cause a drastic drop in performance.

I'm definitely going to buy a gauge and check compression. Winter is setting in here in Cincinnati, and she's about done being ridden until spring. I will be working on it, and I appreciate all experience and suggestions.

 

I'd suspect it to be a sensor or ignition issue,run the diagnostic tests on your stator n voltage regulator. Could there be a parasitic draw on your system causing it? If it were mine I'd be lookin here first.