Considering a trip west to Reno Air Races and then on to Lake Tahoe, Crater Lake, OR and the Oregon coast before heading back east. I'll cross or stay in some higher altitudes,(above 5000ft+). For those that live there or have traveled in the thin air, what was your experience? I know it will run rich and power will be down. The concern is how badly and will I foul plugs and/or have cold starting problems. MPG will also be reduced so range on a tankfull is part of the trip planning too.

 

I'm resisting all inclinations to make any comments .....at this time anyway.

Suffice as to say be sure to pack 3 feet of garden hose.

 

Regardless of what Sprock says, you don't need to pack any sex toys. His M O is different and somewhat unique.

With that noted: Many moons ago my younger brother, my mom, a friend and myself, loaded up a 1968 Plymouth Satellite and headed west. We racked up 6,200 miles in 2 weeks. The trunk was full of a 8 man canvas tent coolers and stuff. The car-top carrier full of lawn chairs, camp stove, sleeping bags and more stuff. We saw 4-corners, Grand canyon, Salt lake, Mt. Rushmore, Niagara Fall and much much more. We did spend some time in the Rockies and went over some passes. I was behind the wheel going up Pike's Peek. I remember putting the Auto in low gear and mashing the peddle to the metal for the entire trip up. We never got over 15 MPH. The 318CI w/2-barrel had all to do to lug 4 people and gear up that hill.

So where am I going? The times spent in the mountain highest areas were few compared to the driving we did at lower elevations. The Plymouth operated quite well in the painted desert and salt lake area.

The CBR with a greater HP/weight ratio will do much better at elevations and personal wouldn't worry about a small amount of very high elevation in the ride. If its got factory jetting its already running lean.

 

TBT, you are too kind. "Unique" really is sugarcoating the real story...but this is a question about operating in thin air not in Sprock's hot air, so I'll move on.

I recall your Plymouth story and had a similar experience with my '79 Mercury in Colorado at 10-12,000 ft. Chugging black smoke, barely idle and using a tank of gas in a 100 miles.

My concern is not so much about the power but more about plug fouling, starting problems when the engine is cold and not having the range to the next gas stop. It may be nothing to worry about but figured that some of our partners here have wondered around the mountains enough to say what to expect.

 

Maybe stay off the choke when cold until you figure it out. LOL

I was just making the point that the percentage of riding would not be worth jetting toward the higher elevations. I have read that auto manufactures map EFI vehicles by zip code, before delivery, for the elevation changes. I wonder what carburetor adjustments if any were.

For the correct answer, someone with a bike in higher elevations would need to know what jet size they are running to give you any useful info.

 

He's already well versed using the "choke" the hose was for extended travel capacity

Quick and easy way to compensate for elevation would surely involve popping off the
carb caps and taking a shim out in conjunction with a 1/2 to 3/4 turns in on you pilot
air needles would it not ?

It's pretty elementary stuff imo but then again it may depend on how long you think you
may be at elevation ! Sounds like a long slow ride at elevation ?

 

Stock jetting works perfectly in the Denver area. Consistently get 40 MPG with a K&H filter. Everything runs crappy running to the top of Mount Evans.

 

I recall some years ago taking an MGB up to the Lake Ohau ski field. Terminal altitude sickness as we got to the top, definitely running rich, felt like someone had pulled the choke on when the engine was at full temp.

But, it was only for a short time, not a lifetime. Deffo not worth messing with the carbs for such a short term problem.

Have also been slightly distracted by the 68 Plymouth Satellite comment. A quick google image search has confirmed that I'd quite like to have one of them parked up in my garage.

 

I'm based near sea level in Oregon and rode my CB700SC (never should have sold that thing. It only had 95,000 miles on it) and the CBR all around the West, including trips to Crater Lake, Lakeview, Reno, and a couple of runs down to the Grand Canyon, etc. over the years, and never noticed anything except a little less 'oomph' trying to pass motor homes up hill at 5,000 feet on a hot day, particularly on the NightHawk. I'd not worry about anything and just go for it.

 

I echo Slowpoke's experience. I live in the Denver area and ride most of the time in the mountains -including the 14k route on occasion. My bike is stock and I have no problems at all. Going to the road he mentioned is a slow run anyway because of the road and critters you might run into ( one mountain goat and a coyote who thought the road was theirs:-). In the mountains no problems starting or running hard at all. Averaging 40+ MPG and sometimes that's 'jamming' in the hills.Only thing I notice is that it runs warmer up there - about half the gauge -fan doesn't come on unless I'm in one of the towns at altitude.One of my favorite 'day runs' is up to Trail Ridge road about 10 - 11k feet. the air is cool enough that it stays about a quarter on the temp gauge most of the time. In short no problems with mine at all.