Yesterday, I was riding with a group of friends in the Sierra Foothills. We were going up a decent, winding grade when at about 4000 feet I noticed a lack of power and a pinging noise. I am guessing it is detonation. My bike, as you can see in the signature, is an '11 RKC w/ the 103. I checked the spark plug gap with a feeler gauge about 100 miles ago as I was getting the bike ready for this road trip.

Everything was running strong until somewhere around 4000 feet. I know it was around 4000 feet because we passed a 4000 foot elevation sign when all of this was happening.

I had this problem many years ago on a carbureted Honda 550. But it would seem to me that a computerized, fuel injected modern engine should not do this. I would guess you guys who live east of the Sierras do not have this problem.

Once we got back down to "sea level" all was running strong again.

It is still under warranty and so I will be taking it in for the dealership to look at.

Very frustrating.

Any comments... Suggestions?

 

the higher you go the less air. your bike was going rich and the ecm was back out. need a better tune.

 

I understand it was going rich. On a carbureted bike you close the jet(s) to reduce the fuel. On a computerized, fuel injected bike the computer should make the necessary adjustments. Especially since it is a stock engine. No stage one or two. No CAT removal. Everything is stock. It should have performed perfectly.

 

Sounds like you may be lugging the engine. How fast and what gear?

 

So it ran fine prior to 4000 feet then ran fine below 4000 feet and you wonder what's wrong? If you dont do that trip often, I wouldn't worry. If you do, get yourself an aftermarket tuner. I bet that's what the dealer tells you when you go. Other than those two options mentioned, its not a warranty issue.

 

the higher you go the less air.

 

The more altitude you gain the less oxygen there is in the air. Less oxygen there is the less power you are going to make. Even if the ecu corrects the fuel and spark accordingly you will be making less power.

4000 ft doesn't sound that high, maybe you just need to down shift a little sooner.

 

Because of the grade and the lack of power I had to keep the RPMs around 3000 to 3200. (I have a tach.)

 

It would seem to me that a stock bike, from the factory, should be able to run well from sea level up to 9,000 or 10,000 feet. After all, when I go Interstate 80, over Donner pass (Which is a little over 8,000 feet), as I am planning on doing, and then traveling to Colorado, a stock bike should perform flawlessly.

Just as any new car does.

Does not Harley sell bikes east of the Sierras?

 

And I am running the 91 octane. I also only use brand name gas. No discount brands.

Chevron, Shell, Valero, etc.