Stalling at high altitude

[awill1]

While riding through the Sierra Nevada mountains my 2005 FZ6 was stalling every time I came to a stop. Instead of a violent motion like in my earlier riding days, the engine just seemed to slow down and fade away. The first few times I thought I might be doing something wrong. Then I began to worry that something was wrong with the bike. It was running normal when I was moving, but once I let off the throttle the engine just faded out. The route I took only had a few stops, so after only a few stops I descended from the mountains and there was no more problem. Once in the valley I switched to the digital tach and the idle rpms were normal.

Is there a good reason my bike would have this behavior in high altitude? Do I need to switch the key to off and back to on to let the ECU adjust to the lower air pressure? My bike is completely stock. Should I take my bike in for inspection before I make the return trip home? I really don't want to ride home if something is wrong.

Thank you in advance.

 

[sideshow_downs]

Because of the altitude the oxygen levels are diffrent. I recently moved from Texas to Colorado and my bike was doing the same thing. It has since self corrected itself and runs much better now.

You cold disconnect the battery for about a half hour or so and the ecu will set itself up for the hight altitude.

 

[Andz]

What elevation are you talking about?

I live at 5,500ft above sea level, and every year I take my bike to Cape Town which is at sea level, and I have never even noticed a difference (apart from the increased power at sea level).

 

[Red Wazp]

Where were you in the Sierra's? How high up were you when the problem was noticed?

I am wondering if your bike was tuned to run where you live (sea level) and being it has carburetors the climb in elevation would be more noticeable. Perhaps increasing the idle speed would have corrected the stalling at idle.
Don't know about the EUC.

I have fuel injection so elevation changes are not a big deal, but on my bike (KLR) with a carb the idle seems the same up high just not much power

 

[awill1]

What elevation are you talking about?

I live at 5,500ft above sea level, and every year I take my bike to Cape Town which is at sea level, and I have never even noticed a difference (apart from the increased power at sea level).

I saw a sign at one point saying the elevation was 7000ft above sea level. I live at sea level and have never taken the bike above 2000 ft before. Everything was running fine in the foothills before the mountains and in the valley after the mountains. Everything is running good again now that I am on the backside of the mountains at 4500 ft. Hopefully riding the bike around at 4500 feet for the next few days will get it adjusted better to high altitude and will prepare it for the trip home.

 

[awill1]

Where were you in the Sierra's? How high up were you when the problem was noticed?

I am wondering if your bike was tuned to run where you live (sea level) and being it has carburetors the climb in elevation would be more noticeable. Perhaps increasing the idle speed would have corrected the stalling at idle.
Don't know about the EUC.

I have fuel injection so elevation changes are not a big deal, but on my bike (KLR) with a carb the idle seems the same up high just not much power

I was above 7000 feet. Like you said, I do live at sea level, so I was hoping this was the case.

Does the 2005 FZ6 have a carburetor? I thought it was fuel injected.

My route had so few stops along the way so before I knew it I was on the other side of the mountains. Now I am just worried about the return trip home.

Thanks for all of the responses so far.

 

[Red Wazp]

I beleive 07 was the first year of fuel injection. Sounds like you are riding near Yosemite?

Don't sweat the stalling, just don't stop

As mentioned try bumping up the idle. Bikes with carbs are not real happy above 8K feet.

 

[Andz]

I beleive 07 was the first year of fuel injection

They all have fuel injection. My 04 certainly has.

 

[awill1]

Thank you everyone for your help. I was able to safely ride home through the mountains without any more problems.

Upon further inspection, my idle speed at 4500 feet above sea level was low (1050-1150 RPM) so I increased it to spec. I also moved the tool kit to my saddle bags so I could get at them easier if I ran into any problems. With the idle reset everything ran much better through the twisty roads around Lake Tahoe. I only had to stop at a few stop signs, but the engine never came close to stalling. When I returned to sea level my idle rose significantly (1600-1700). I lowered the idle and rode on. It has held strong within spec ever since.

I learned 2 lessons from this trip:

1. Gains of 7000+ feet in altitude are enough to lower the idle to the point of stalling.
2. Moving the tool kit from under the seat to a convenient place when the bike is in loaded up in touring mode can save a lot of frustration if there is a need for minor tweeking.

Thanks again for all of the help.