I recently was on a long bike trip,that took me over a number of high mountain passes, and every time we got high up there, I noticed the engine oil temps were much higher than I typically see. I don't recall the exact temps, but it got me wondering why it would get hotter as I got higher in elevation. I would think the AFR would be getting richer, due to less air at the higher altitudes. So I am not understanding why it gets hotter. It should be cooler due to a richer A/F mix. Caveat. I am running a 2013 103 RG, stage 1 intake and exhaust, cat free headers, bigger valves, ported and polished heads, stock O2 probes and digital fuel pack tuner ( for now). Bike runs just fine except around 3000 rpm I have some roughness at constant throttle, but we are working on that issue currently. Does the bike have auto lean? If so, is that adjustable? Can someone explain why it would be getting hotter? Just wondering.

 

Couple of things...fuel injection usually adjusts automatically for elevation, so it is highly doubtful that your engine is running rich at altitude. There is less oxygen (same percentage but lower amount) at high altitude so modern FI reduces the amount of fuel put into the engine to make certain there is still a fairly clean burn.

Second, you are probably getting higher temperatures because your engine is not only working to move you and your bike, but also lifting the bike against gravity as you ride up the mountain. Living here in Colorado I see dozens of vehicles every year that have overheated while trying to go up hill.

 

Guess that's about as good a response as you can get. They were longer grades, obviously.Guess that makes sense

 

Also consider as you go up in altitude you will add more throttle to maintain a given speed, which means you will be operating above the sea level throttle openings you are used to.

That said, if your bike has not been properly recalibrated (dyno tuned) and relying on the fuelpac to tune specific points that were not in play at sea level...

Too rich or too lean at the rpms/load you are referring to can/will also cause elevated temps because the engine is out of tune and requires more throttle to get enough power to push the boat up the hill.
Bob

 

While you need more throttle to keep going you are still making the same HP as sea level, possibly even a little less.. The problem is that at altitude the air is less dense and therefor less heat is conducted away from the cylinders and heads.. Motor runs hotter.. Mileage gets better tho.. As stated going up hills heats the motor.. Much more than going down.. :-)

 

On top of Pikes Peak two weeks ago I thought my 16 RK was gonna burn down. Don't know about the science of it, but it was hot enough to smell my bluejeans scorching when I was getting off the bike and they hit the CAT. The CAT is no longer on the bike and it seems to run cooler during everyday riding, but I'm not going up the Peak again to find out. THe bike ran like crap with a factory setup tune and all the damn tourists kept stopping in front of us on the switchbacks. Ain't easy to hold up an 800 pound bike, going uphill at a lean, and then get started again on a bike that don't want to run right.

 

lower air density at altitude reduces the heat loss from the machine. think dewar flask...this plus of course all the work the machine is doing combined with the fractional thermal efficiency of otto cycle engine...means maybe 60% is waste heat, maybe more, but lots of waste heat. getting rid of waste heat to an atmospheric "ultimate heat sink" when there's less atmosphere is tricky - radiation losses become more important.

 

I seriously doubt that the bike would spend much time in closed loop mode during
the type of riding the OP has mentioned. Its only in closed loop mode that the bikes ecm would adjust to the altitude.

 

Yep, when you start going up I-70 you start to see how hard the bike (and cars around you) have to work. It only feels like a slight hill, but man it's brutal.

This guy sounds legit.


TL;DR - It's harder to go up hill, work hard = heat.

 

You lose about 3% hp per 1000' in elevation. So your 100 hp bike now has 42% less hp at the top of Pikes Peak. That is significant. One advantage is you ride from 100degree air in Co springs to 60 or less on top. They had snow up there a few nights ago.