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Discussion Starter · #1 ·
My DH was told by an owner of a carbureted bike to be aware of how changes in altitude can affect the fuel-injection, essentially shutting it down and causing the bike to stall unexpectedly. :eek: I haven't seen anything on this and would like to know if this is just bike-envy :cool: or if there's a legitimate concern.

I don't ride in an area with sharply changing altitude, but am participating in an easy mountain ride on Saturday and just want to know if this is something I should even have to think about. :eek: Thanks for your input!
 

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I hijacked this from a ducati forum

It will run slightly richer at altitude because the fuel map is purposefully programmed to only make a partial correction for high altitudes. If your engine is adjusted properly at sea level it will still run well at altitude. You will lose a bit of power due to the thinner air but at higher speeds your air resistance will be lower so this is somewhat self-compensating and you should not notice a drastic reduction in power except at slower speeds.

In my limited knowledge of EFI's on motorcycles I would say that they would all be about the same
 

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My DH was told by an owner of a carbureted bike to be aware of how changes in altitude can affect the fuel-injection, essentially shutting it down and causing the bike to stall unexpectedly. :eek: I haven't seen anything on this and would like to know if this is just bike-envy :cool: or if there's a legitimate concern.

I don't ride in an area with sharply changing altitude, but am participating in an easy mountain ride on Saturday and just want to know if this is something I should even have to think about. :eek: Thanks for your input!
What altitude are you talking about riding at? I live and ride at 7000 to 10000 ft. above sea level. I run the motor at 6500 to 8500 rpm. At these altitudes you have to be willing to spool this motor up to get it to go anywhere.
 

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Discussion Starter · #4 ·
What altitude are you talking about riding at? I live and ride at 7000 to 10000 ft. above sea level. I run the motor at 6500 to 8500 rpm. At these altitudes you have to be willing to spool this motor up to get it to go anywhere.
I'm laughing at myself now... the ride will cover altitudes from ~2,100 ft. to 300. WOW--10K ft. sounds amazing! And, if you haven't had any problems, I'm not worried about it. :p

Thanks guys!
 

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You'll have no problems as far as the EFI compensating for altitude... enjoy the ride!
 

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My DH was told by an owner of a carbureted bike to be aware of how changes in altitude can affect the fuel-injection!
The guy with the carburetor should be the one to worry if he went up to 10,000 on a bike set up for sea level. Fuel injected bikes correct for thinner air with the signal from the manifold absolute pressure sensor. The fuel injection on the CBR250R is actually one step advanced beyond many mid 2000 era fuel injected bikes with it's closed loop O2 sensor which allows the mixture to adapt to differing altitudes even beyond what the manifold absolute pressure sensor will do, with actual ongoing measured feed back.
 

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I'm laughing at myself now... the ride will cover altitudes from ~2,100 ft. to 300. WOW--10K ft. sounds amazing! And, if you haven't had any problems, I'm not worried about it. :p

Thanks guys!
ive rode up as high as 6000 + feet so far in the mountains here...rides just like it does at the base of the mountain...didnt have to change my riding style at all....kept it below 5000k pms most of the ride....i wouldnt even waste my time worrying about this anymore
 

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Discussion Starter · #8 ·
The guy with the carburetor should be the one to worry if he went up to 10,000 on a bike set up for sea level. Fuel injected bikes correct for thinner air with the signal from the manifold absolute pressure sensor. The fuel injection on the CBR250R is actually one step advanced beyond many mid 2000 era fuel injected bikes with it's closed loop O2 sensor which allows the mixture to adapt to differing altitudes even beyond what the manifold absolute pressure sensor will do, with actual ongoing measured feed back.
Sendler, I don't know what you do for a living, but it should be teaching others about their motorcycles and how to get the most from the experience of riding them. Thanks so much for this technical explanation... while I don't understand most of it, it makes 110% confident in my CBR! :D
 

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Sendler, I don't know what you do for a living
I am a 29 year mechanic at a Mercedes dealer.
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The MAP sensor senses the air pressure that is ready to go into the combustion chamber. There is also an intake air temperature sensor. Cold air is more dense. And a position sensor for how far open the throttle plate is. The computer puts this information tofether to calculate the mass of the air that is being used at any given moment and turns the injector on for the correct amount of time that it needs to squirt out the right amount of fuel.
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As the air gets thinner at altitude, the pressure sensor gets lower and lower and so the computer knows to open the injector for a shorter time to keep the fuel/ air ratio the same.
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The CBR also has an oxygen sensor that sniffs the exhaust all the time the engine is warm. When it sniffs O2 the computer adds a little extra fuel until it doesn't sniff any residual O2 that didn't find a piece of fuel to burn up with. Then the computer gives out a little less fuel which will leave some unburned O2 again. Ect. Continually back and forth on the edge of perfectly using up all of the oxygen and fuel that the engine has drawn in. This is a closed feedback loop.
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Cars are a couple generations more advanced but this is a pretty nice system for a $4100 bike.
 

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Discussion Starter · #10 ·
I am a 29 year mechanic at a Mercedes dealer.
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The CBR also has an oxygen sensor that sniffs the exhaust all the time the engine is warm. When it sniffs O2 the computer adds a little extra fuel until it doesn't sniff any residual O2 that didn't find a piece of fuel to burn up with. Then the computer gives out a little less fuel which will leave some unburned O2 again. Ect. Continually back and forth on the edge of perfectly using up all of the oxygen and fuel that the engine has drawn in. This is a closed feedback loop.
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Cars are a couple generations more advanced but this is a pretty nice system for a $4100 bike.
I knew it! ;) Thanks, Sendler--this is a fantastic explanation and now I understand why people talk about mapping device upgrades. Interesting. I sinccerely appreciate the time you invested to share your knowledge and expertise with me! :)
 

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Discussion Starter · #11 ·
Happy to report I had my CBR in the Blue Ridge Mountains of Virginia on Saturday with altitudes varying from 3,200+ to 300 ft. covering more than 200 miles and she never missed a beat! :D


I {HEART} THIS BIKE!!!
 

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Going to ride straight there? Or one of many stops?

I am just waiting to take this bike out for a long haul this summer.:D
 

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I probably won't have time for Mount Evans this year. Maybe next year. The Denver crew is all coming to NY for the first time this year. I am going to Americade for the day in June and also camping for a couple nights in July to ride with Craig Vetter and the streamliners at Mid Ohio.
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Stopping at the Moto GP in Indy on the way to Denver would make a good trip.
 

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Discussion Starter · #15 ·
I am just waiting to take this bike out for a long haul this summer.:D
I'm anxious to explore farther now... just ordered some saddlebags Tour Master :: Luggage :: Select Saddlebags so I can pack a bit of stuff and go for a weekend of riding. :D

The Blue Ridge Parkway Blue Ridge Parkway - Home offers 469 miles of scenic vistas and winding roads. Skyline Drive is 100 miles of much the same north of I-64 towards Front Royal, VA.
Blue Ridge Skyline Parkway Drive - Skyline Drive General Info
 

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I probably won't have time for Mount Evans this year. Maybe next year. The Denver crew is all coming to NY for the first time this year. I am going to Americade for the day in June and also camping for a couple nights in July to ride with Craig Vetter and the streamliners at Mid Ohio.
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Stopping at the Moto GP in Indy on the way to Denver would make a good trip.
I am still contemplating doing Americade on the 9th.

Sadly my prof is having final presentations on Friday or I'd go then. I may be able to do in Thursday. I imagine Saturday is the most crowded. The site says I can't post-register on Saturday though....
 

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I'm anxious to explore farther now... just ordered some saddlebags [/url]
U.S. 421 runs from Lexington VA to boone NC...the best part of the road aka "the snake" is around shady valley TN between mountain city and south holston lake///alot of people compare it to the "Dragons tail" several hours south ..going to ride it again myself sometime soon
 

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I am still contemplating doing Americade on the 9th.

Sadly my prof is having final presentations on Friday or I'd go then. I may be able to do in Thursday. I imagine Saturday is the most crowded. The site says I can't post-register on Saturday though....
Saturday at Americade is very crowded. I'm going Wed. or Thurs. depending on the weather. I have to get up at 4:00 so I can be there by 9:00 to sign up for rides. I hope Honda will have the NC700X there and I should ride the V-Strom also.
 

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Ok. That's what I thought. Are you doing the post-registration that morning?

Wednesday is a no go for me, I have yet another final presentation to do.:(

I will try for Thursday. I guess I'll have to leave quite earlier to get there at 9. I wanted to ride those bikes as well.:)
 
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