Just bought a 2007 Road King with 103 cu in engine and EFI. It runs rich and very rough at idle, but smooth at speed.There are black deposits in the exhaust pipes and the lower threads of the spark plugs which imply running rich. It appears to have stock exhaust and air filter. Any ideas? I can find no codes stored in the computer that relate to this, just some maintenance, parts replacement codes.
Doc

 

ANY codes should not be there. There is no such thing as "maintenance" codes. What codes were stored in the ECM. I would also look around (under seat) for an add on Piggy controller.

 

The codes were U1097...speedo serial data loss, PN 34448-07, PN 68920-07, PN67033-046, PN67042-046. Perhaps you can interpret them. The speedo and cruise work fine. I assume the parts numbers refer to previous replacement, but am only guessing.

 

I don't know what a piggy controller would look like, but I installed a factory cruise control recently and saw nothing that looked adjustable under the seat.
Doc

 

103 with stock AC and exhaust? Bwaha! I think I have a possible answer.

Somebody took off their high performance ac and pipes before selling or trading in their bike. You got stuck with stock ac and pipes, on a bike that was tuned for higher flow!

No way a guy will build a 103 and leave the most important parts stock. You are running pig rich, and likely will keep fouling plugs as fast as you can swap 'em.

 

Good call but that would only apply of the prior owner was running a fuel management system that reprogrammed the ECM, like a SERT. However, a SERT or similar system that marries to the ECM/VIN would have no value to the previous owner, but the previous owner may not even know that. On the other hand, a piggy back system, like a PCIII would have been pulled off for reuse or resale and the stock ECM reverted to the stock map.

A more likely scenario but having the same results would be that the the 103" was a dealer build and the ECM was dealer flashed. Have you checked your mileage? I would bet it sucks.

I think Ed is right on and your best bet would be to install a fuel management system and have the motor tuned. Your idle issue will go away, mileage should improve and generally run better.

 

Have you cleaned the IAC port in the throttle body?

If not?
Partially plugged? It can cause your problem.

Al

 

I bet he'd be in the ballpark if he added some pipes and a free flowing A/C.
Odds are he has a flash or a sert program (as you said), either way he's gotta do something.
I agree, no way he'd leave a power commander if he scavenged the other parts. (It would be hilarious if he did).
Simply unplug it. He he!

 

Hi Guys, Great suggestions. I will follow them up. One issue, though. I bought the bike directly from the city police department (Rome GA.). They said it was dealer maintained, so I doubt anyone was motivated to remove any parts. Of course, anything is possible.

 

Now that is interesting.

I see the reason for a 103 with stock A/C and pipes.

Is the air filter real dirty? Sure does seem like you are running pig rich.
The dealer might have given them and ECM flash because of the added cubes, and the stock A/C and pipes are VERY restrictive.

Sure would be nice if you could have it sniffed, on a dyno to see how rich it's running. Having confirmation is always sweet.

I wouldn't hesitate to put a free flowing air cleaner on there. Obviously you have room to go leaner.

Edit: Still seems the exhaust sensors would be trying to lean it out if they were working.
However, if the base map is super rich, the sensors only compensate a small amount.

I'd still start with a free flowing air filter.



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