Sea Level to 7000' on a R100S?

[jjwithers]

I plan on riding my 77 R100S from the west coast to Santa Fe, NM for a job in a month. I used to live there and love the excuse to travel back to New Mexico and eat Green Chile.

I'm starting to prepare my bike for the trip and I am beginning to wonder if there will be any issues with the standard 40mm carbs and the altitude?

Is there anything I should know or be prepared to do as I climb in elevation?

[Bamboo812]

I regularly change elevations more than that with no problems, but it helps to lean the idle mixture a bit at higher altitudes. That said, I rode my R75/5 to the top of 13,900' Mauna Kea one time. It idled OK, but was a bit down on power. There's only 40% of the oxygen level at sea level up there.

[Major Softie]

If you have stock (CV) Bings, then you'll have no problem other than the aforementioned reduced power, and there's nothing that can be done about that without superchargers/turbochargers. The CV carb design compensates for altitude better than conventional slide carbs.

If you had slide carbs, you'd probably have to adjust your idle, and the bike would run a bit rich, but it would still work okay - 7000 ft. isn't that big a deal. I live at 6500 and have to cross passes from 7500 to 9000 feet, and then drop down to sea level, and my old slide carb bikes would just get a little funky up around 9000. From sea level to 7000 they were always fine.

[wookie]

This may be oversimplifying but when I spent time in the Rockies (on my '77 R100S) and I felt a let-down in power, I downshifted. Voila; instant pick-me-up. and no fooling around with jets.

Wookie

[Major Softie]

This may be oversimplifying but when I spent time in the Rockies (on my '77 R100S) and I felt a let-down in power, I downshifted. Voila; instant pick-me-up. and no fooling around with jets.

Wookie

Yeah, that works on a 1000. Tim's talking about 14,000 ft. I'm not sure my R50/2 could have climbed a 1% grad in first gear at 14,000 ft.

[Ken in Oklahoma]

Yeah, that works on a 1000. Tim's talking about 14,000 ft. I'm not sure my R50/2 could have climbed a 1% grad in first gear at 14,000 ft.

I recall with amusement the phrase you coined some years ago relative to your R50/2 and it's acceleration. You called it "gathering momentum".

Ken

[bbelk]

I live at 500 feet in Texas and spend most of my summers outside of Aspen at 7,000 - 9,000. My R65 loses a little bit of power, but runs fine. I have found that I save a lot of battery by changing my spark plugs every couple weeks. It runs a little rich and they blacken up pretty quickly.

[jjwithers]

This is good news. Thanks guys. Now I just have to worry about everything else that can go wonky. before the trip, I have work to do:
one caliper needs to be rebuilt,
slight generator light glow that I have tried many times to solve,
i hope to re-spline my final drive , etc...

[Bamboo812]

Get the spline job done at Hansens. Two week turnaround. Brunos is currently buried in work and it can take many months...

[jjwithers]

We can actually do the splines here in Los Angeles. I'm not the one doing the work... so I can't claim my expertise but the guy I work with repaired a few already. Check out Oshmo.com for some of the services we can do.
I replaced wheel splines on the last bike I built.
We lighten flywheels in-house and we are working on some other services too....