During my last trip I felt at a certain time a kind of loss of power. It is also true that I picked up a 70 kg passenger but it did not seemed to me a big change.
First I removed the spark plug cable from each cylinder one at a time and the difference was significant. So the spark plugs are working. But after I removed the spark plugs there was a difference between the. The front cylinder's spark plug is more blackish than the other one that is not so.

I have a 2002 RK FLHRI. Is it possible to be some air-fuel mixture ratio changed and that to be the reason for loosing power? Or any other suggestions are welcome. Thanks.

Here is a picture with the spark plugs:

Also I noticed that the oil level is bellow the normal level.

 

NEVER pull the spark plugs or wires and run or crank the motor...the ignition module and /or ignition coil can be damaged.

to move a 70 kg passenger will be equivalent to about 12 horsepower...

riding at high elevation, less oxygen is available, so power will be reduced

how is the bike under your normal riding conditions?




Mike

 

Under normal condition the bike runs ok. It has a SE Fuel management and also modified air filter and exhaust.
Can this symptoms come from the need of oil change soon?

By the way, how can you check if the spark plug works otherwise than pulling the cable for a very short time?

 

Realize that I am a long, long way from Romania but from here I would say that the first thing I would do is put some new Harley Davidson brand spark plugs in your machine. Those plugs looks like they might be some of those "specialty" plugs you see advertised from time to time. As far as the color of the plugs, more often than not the rear plug will be a little bit whiter than the front plug because normally it runs a little bit hotter due to the fact that it is not out front catching all that cool air coming over the front fender. I don't think oil is your problem unless it is very low on oil and is overheating.
Do you guys have any additives in your gasoline (like ethanol) over there like we have in the United States?

 

Have you checked your wires? I was experiencing random check engine light coming on, I figured now that my bike was 6 years old that the wires needed changing. I removed them to measure the length and inspect, and found some rub marks on the wires. When I put them back on I made sure there was no contact. My engine light hasn't come on since.

Also make sure your plugs aren't getting loosened, I had that happen until I read in the service manual that they tell you to use some loctite on the threads.
That was the source of a ticking sound from compression leaking and loss of power.

 

LocTite on plug threads? The heat would break it down pretty fast....
New one on me, I torque them down to spec, lossen them a tad and then re-torque them. Never had one come loose doing that.

 

Yeah right out of the service '07 service manual. I always have done like you said, I was nervous about applying too much so I lightly covered half the threads. I had this happen on a couple of old v8's but never would have thought to use loctite.

 

That would be anti-seize on the threads, not loc-tite..
Nothing wrong with using NGK Plugs either.
They are not "specialty plugs" either.
It's what my tuner uses and myself as well.

 

Now Anti-Seize is the ticket...I use that also....

 

Will the NGK plugs and HD's anti-knock system work together? What I am thinking is the plugs and the anti-knock system are not totally in sync, putting the bike under high load (like a heavy girl , but hey, even heavy girls need lovin too) the engine knocks, gets detected and the ECM retards the spark. If not working spot on, ie with non HD plugs, the system could over compensate retarding spark so much as to greatly reduce power. Just a thought.