Also even with proper jetting power will go down with elevation as the atmosphere is still 21% O2 but the total pressure is lower as you go up and no matter how spot on your jetting is you will suffer from lost power due to an overall decrease in O2 pressure.

 

I have always noticed a significant increase in horsepower on every bike I have ever ridden out to the Pacific coast from where I live at 1100m

 

Is the Acerbis for a 2012? Will it fit with no modification to the body? I heard some interfere with the choke and you can't use your plastics anymore.

 

With the seat concept, does it make it taller? I'm already on my toes with the bike, but the stock seat is not pleasurable for long trips I've come to decide.

 

A normally aspirated i.e., non turbo-charged engine will loose approximately 3%+- per 1000' elevation/altitude gain. Additionally, warmer than standard temperature for any given elevation also decrease's air density, resulting in a higher "density altitude" than the actual elevation. For instance, if the temperature at 4000' elevation is 90F the "density altitude" will be 7000' feet and your engine will perform just as if it is at that elevation. Atmospheric pressure deviations (lower) from standard can also increase the "density altitude" although typically not as significantly as high temps. Pilots are very familiar with this because it can be critical to aircraft performance.
Proper jetting etc. is important and will permit maximum efficiency but cannot make up for the loss of power! At 4500' if the temperature is at standard a loss of approximately 13.5%+- h.p. from Sea Level output will result. If the temperature is colder than standard the loss will be less as the density will equate to a lower elevation. If warmer, the opposite will result. BTW: "Standard temperature" at S.L. is 15C/59F. The standard adiabatic rate of change per 1000' change is appox. 2C. That said the standard temperature at 4500' is approx. 6C/43F, so anytime the temperature at that elevation is warmer the equivalent "density altitude" will be higher.
I am not trying to be a smart ***, just trying to pass on a bit more accuracy to the topic. Please do not take offense as it is not intended.

 

none taken. It's a complicated subject and I'm happy for the OP somebody has a better grasp of it than I. It's been a long time since I hit the fluid mechanic books. I shouldn't oughta been shooting from the hip like I did.

 

I have seen meters that specifically measure the air density... Hard-core tuners use them.

I'm constantly fiddling with the jetting on my sleds. I know the altitude I ride at, but winter temperatures fluctuate quite a bit. Same principle as you mention... One of those meters would come in handy for getting it set up correctly.

 

RAD meter mounted in the sled trailer. Why I switched from yamaha to skidoo. the HAC and DPM was sooooooo nice.

 

Umm, I don't think it makes it taller but haven't noticed. On this I would defer to those who have had it longer. It seems a bit wider in the part of the buttocks that makes contact with the seat plus the whole thing does not seem to split all right up to where most of us don't seem to have much padding. IMO.
Good luck....

 

Thanks. There's a ton that I don't know about motorbikes which is why I rely on those of you who do. What little I do know, like most of you guys/gals, I try to share. BTW: Didn't think you were shootin from the hip, it just wasn't as accurate as you were led to believe. I think we've all done that, and I'll probably not give warning before I do it again.