I just picked up a 2010 Sportsman 800 EFI from near sea level in Texas and brought it up to 9000' in Colorado. Most of the riding will be done from 8000' to 13,000'. The manual states that the clutch weights need to be changed, but I've also heard that it needs to be re-mapped. Is this correct? Any other modifications needed?

 

I thought the whole advantage of EFI was you had to do nothing to them for any altitude change?

Never heard about clutching mattering unless you buy big 28" tires and love mud riding.

 

Clutching should be adjusted for the higher elevation. For that high of elevation just follow manuals reccomendation for clutching.

Not 100% sure on mapping but believe you shouldn't have to change anything. I would call a dealer in your area at the higher elevation to make sure.

 

The EFI should be fine. You need to change clutching due to the loss of engine power as you go higher. This is my limited understanding of things. I know my GMC 6.0L V8 felt like a 6 cylinder when we went through Wolf Pass in Colorado.

 

The change in clutch weights apparently has to do with when the transmission shifts depending on engine RPMs.

Yeah, MooseHenden, Wolf Creek Pass is 10,683' and we live at 9000'. Our nearest pass is Cottonwood Pass at 12,126'. It can be rather hard for me to breath at that elevation, so I can imagine the atv feels the same.

 

I think what they would do is change it so there are more RPMs built up before engaging so you have more power at the bottom end.

Back in 2004 I went to Yellowstone and we walked around looking at the geysers and other thermal features. I couldn't believe how winded I was. Then it dawned on me that I live at and am used to being around 100' of elevation and here I was wandering around at about 8000'. I can't imagine what it's like for the people who go above 20,000 ft. to climb a mountain. I guess they don't call it the "death zone" for nothing.

 

Your mapping of the EFI does NOT need to be changed, neither does the clutching tho to get optimum performance out of your machine clutching makes optimum power for the altitude you will be riding at. (On Average) Any internal combustion engine will loose 10% of its power for every 3000 feet gain in elevation therefore re clutching for this kinda loss wont make your machine feel so underpowered and using the most of what power you have.

To give you a idea My Grizz 700 was clutched on a Dyno and will run circles around most 800 without a clutch at this altitude.

 

Dodge57Hemi, based on those figures, I'll loose 30% of my power at 9000' without changing the weights? That doesn't sound good. Thanks for the info, though.

 

Remember that is on average! Every engine is different and the more CC's you have the better off you will be. When you live here you learn to keep a clean air filter! LOL

 

We ride between 9000 and 12000 feet then go to Utah and ride at 3 to 4000 with our 500's and 850, I have never changed anything. You do lose power but these have so much even the 500's can climb anything on the trail faster than I need to be going. It would be a hassle to change things 4 or 5 times a year for the little difference it makes.