Would 1700 ft. in elevation make much of a diffrence?

[chris200x]

I had some family come up this past weekend riding dirtbikes. They live down at or just above sea level. They're rides were running something terrible. Breaking up in the higher RPM's.. Hard starting. They swore to me that back home their Kawasakis ran good.

We live around 1700 feet above SL. Add in some of the coal banks around here and you could probably add 2 or 3 hundred feet more in some instances. Do any of you think that the elevation had something to do with this. Or were they just pulling my leg? I don't think that little diffrence means much at all.

Also,, maybe a size or two bigger main jet in their carbs help this situation?

[wanta250r]

I don't think that little difference in elevation change would do anything. I live above 4,000 feet in elevation and when I take it down to around sea level-500 feet I can barely notice a difference.

[chris200x]

Hmm, I'm a little lost then. These were two strokes and I know they can be a bit finicky at times. what else could it be then (oh all bikes are stock btw)

Could rain and humidity have anything to do with it?

[Dammit!]

When I moved my R from Ohio to Arizona, I had to jet it leaner. It was breaking up at WOT. The elevation difference isn't that much (I think I'm around 1100ft here) but the air is a lot different. Totally dry versus 99% humidity.

Edit: a quick temporary fix is to just pull off the airbox lids.

[250r'en +TCB]

hit the nail on the head. The type of air makes a big differnce. You can make an elevation change of on 10ft but if you go from florida to arizona there gonna be a huge difference in the air!!

I am going to climb Mt. Washington on july 15 with my R. You go up a road but the top is just over 6000ft! My R is around 500ft above sea level hear so I wonder how much I'll have to play with the carb. I won't be doing anything really major, basically the machine just needs to run good enough to get me there hahaha

[Dammit!]

I am going to climb Mt. Washington on july 15 with my R. You go up a road but the top is just over 6000ft! My R is around 500ft above sea level hear so I wonder how much I'll have to play with the carb. I won't be doing anything really major, basically the machine just needs to run good enough to get me there hahaha

Jet it to run good with the airbox lid on, then as you ride higher, once it starts to crap out a little, pop the lid off. The higher you go, the more air it will need due to the decreasing density. Not a perfect solution but it works to an decent extent.

[chris200x]

Well they may have to come up with a better solution when they come back up the end of July. i dont think taking the airbox lid off is a good idea. See.. here if its wet its always real muddy and if it's dry the coal dust is just terrible. Maybe i should suggest to them running the outerwear over the filters. Idk? Maybe I will suggest just buying a good ole Honda four stroke eh?!

[250r'en +TCB]

Maybe I will suggest just buying a good ole Honda four stroke eh?!

Soon as they make a 250cc 4-stroke that can even have a snowball's chance in hell of keeping up with my 21 year old 2-stroke I will be glad to change over!
Anyway I no longer have an airbox, just a UNI with an outerwear. When I'm up in that elevation I don't need it to run perfectly, just needs to get me there basically
-Devin