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Discussion Starter #1
I need some help figuring out why my 2017 AT is running like **** at altitude.

Basically on passes over 4000 meters (13000 ft) the engine will stumble and run poorly. At first it seemed like it would only happen when cold but getting up to 5000 M it would have issues even hot.

It stumbles and coughs almost as if it is running way too lean (opposite of what I would expect) and can’t rev above 5K rpm even in neutral.

I am riding with a friend on a 2018 ATAS and he has no issues.


Today it seemed fine climbing the mountain and started having issues only after I shut the bike off for a couple minutes. But this time instead of disappearing as it warmed up the problem continued until I got below 4000 meters.


Any ideas?
I checked the air filter and valves already, and ruling out bad gas as my friend didn’t have an issue
 

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MAP sensor more than likely, the fact you only have a problem at a lower pressure atmospheric and the air filter is clean. Might be a vacuum leak but only at altitude more than likely not.
Look on page 4-53 in the manual. Not an easy change, behind the air cleaner assembly. I couldn't find the part number or price. But other MAP sensors are less than $200.
 

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The highest pass in the US is Mount Evans at 4,350 meters. I did have some sputtering on a fuel-injected bike and had to keep revs high near the top. Otherwise, below that altitude I've never experienced an issue with any bike.

Unless your riding on the world's highest motorable passes it's unlikely that you'll be above 5000M.
Have you got your measurements switched or do you live in Argentina, Bolivia or India?

https://www.dangerousroads.org/rankings23/166-the-highest-motorable-road-passes.html
 

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Discussion Starter #5
I’m actually riding in Tibet right now and crossing over to Nepal soon ?. Highest pass so far has been almost 5400 meters

I think tomorrow I will finally be down to around 2800 M elevation to see if it makes a difference, but after more riding I don’t think it’s altitude dependent anymore. Just happened to show up at the same time.

Many times when I start it, it will either be able to rev fully through the rev range or get stuck around 5-6k rpms. If I shut it off and restart it it fixes it. It may take a few tries but usually solves its.

I have to check the codes but I’m starting to think I have some crap blocking the fuel filter. When I turn it off, it releases suction and it’s a gamble if it opens up again when restarting. At least that is what is going through my head and seems similar to when my friend’s ATAS had gunk in the tank from the overspray issue. I’ll be in Kathmandu soon and have time to take off the tank and check.

Maybe I’m hoping it’s this so I don’t have to find new parts ?
 

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Sounds similar to what my atas was doing before it was fixed. By keeping the tank full I was able to make it back home with mine (1300 miles). And the restart worked for mine as well. It turns out that it was not overspray but something flaking off from the welds in the tank. I know how frustrating it is , because you get the feeling it’s gonna die and strand you. Good luck!
 

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I’m actually riding in Tibet right now and crossing over to Nepal soon ?. Highest pass so far has been almost 5400 meters

I think tomorrow I will finally be down to around 2800 M elevation to see if it makes a difference, but after more riding I don’t think it’s altitude dependent anymore. Just happened to show up at the same time.

Many times when I start it, it will either be able to rev fully through the rev range or get stuck around 5-6k rpms. If I shut it off and restart it it fixes it. It may take a few tries but usually solves its.

I have to check the codes but I’m starting to think I have some crap blocking the fuel filter. When I turn it off, it releases suction and it’s a gamble if it opens up again when restarting. At least that is what is going through my head and seems similar to when my friend’s ATAS had gunk in the tank from the overspray issue. I’ll be in Kathmandu soon and have time to take off the tank and check.

Maybe I’m hoping it’s this so I don’t have to find new parts ?
Ameen, are you blogging your trip or doing any ride reports? I'd love to hear all about your trip! Hope you're taking lots of pictures! ?
 
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