1981 GS850G Altitude correction idea

[SteveR]

I am based in Houston (sea level) and the mixture is set up just right. My bike is completely stock.
On a trip this summer to Yellowstone I noticed the higher I climbed the richer the bike. So, I opened the air box and removed the filter and the fuel mix leaned out.
My idea is to make a hole in the air box on the carb side and adjust the opening for high altitudes. This way I would not need to remove the filter.
What do you think?

[Dave8338]

Sounds like fine tuning a Model T Ford. It worked then...it'll work now.

[Steve]

How often do you get to higher altitudes, and how long do you stay up there?

Going richer is safer than going leaner, so, although you might lose a bit of power while at altitude, is it really worth all the effort? You would really have to do plug chops at altitude with different airbox openings to see what is the right amount of opening to get your jetting correct.

Go for it if you want, but it sounds like too much bother for me.

[tkent02]

How often do you get to higher altitudes, and how long do you stay up there?

Going richer is safer than going leaner, so, although you might lose a bit of power while at altitude, is it really worth all the effort?

Removing the airbox lid on my '79 GS1000E is the difference between riding slowly to 14,000 ft. or not getting there at all, the bike is adjusted very well for 5,000 ft to start with.

With you newer bike and it's CV carbs it should be a lot less rich at higher elevations, should run fairly well if a little underpowered.

Looking to go fuel injection so it won't be an issue anymore. :-)

[bwringer]

Make a sliding door in the airbox, then rig up a bag of Fritos using some duct tape and baling wire so that the expansion of the Fritos bag at higher altitudes yanks the door open. The higher you go, the wider it opens.

Some say it's OK to use a bag of potato chips or Funyons, but I'm a firm believer that the higher density of Fritos helps maximize your air/snack ratio and thus gives you the most effectiveness.

You'll need to experiment with various size Frito bags to achieve the proper leverage ratio. The two ounce bags in most gas stations are usually a good starting point.

Also, beware of the flimsy packaging used for "off brand" corn chips. Some of these have been known to explode near the summit, scattering salty snacks everywhere and allowing the airbox door to slam shut, which hinders progress greatly.

The Fritos oxygen enrichment system also has the advantage that if some other mechanical problem waylays you in the mountains, you can open the Fritos as a last resort and stave off hunger for a little longer. This could help avoid an ugly "Donner Party" type situation.

[SqDancerLynn1]

I went over Tioga Pass-Yosemnitie on a sohc 750 Honda. Going up at 8-10K ft I was thinking I could push it faster. Yes the thin air does a # esp on low compression motor

[psyguy]

lol, brian