altitude changes

[ginzo]

Still waiting for my new '03 to be put together.  In the mean time, I have a question related to altitude and carburetor jetting.

I live in Dener (5200 ft) and I plan to ride in The Rockies on weekends (up to 14,000 ft).  Longer term, I will probably ride back to my homeland in New England (sea level).

What affect with these altitude changes have on the Valk?  Will I have to re-jet on the fly?  If so, will this affect carb synch?

I have a `99 Valk that I installed a K&N jet kit and since then have ridden as far as Boise Idaho on one occasion and Medford Oregon on another without any problems. I live not too far from San Francisco so I'm at sea level and my trip to Boise took me over Donner Pass so I have experience a little high altitude traveling, again, no problems. The only thing I have noticed was the bike idles a little lower at higher altitudes. I've changed the plugs a couple times since then and they look just fine. You got my curiosity up so I thumbed through the shop manual and it says at higher altitudes (above 6500 feet) turn the air screws in 1/2 turn (1 1/2 turns out is stock), other than that I'd say if your bike is stock you'll be able to go coast to coast no sweat.

On the subject of what octane to use, I'm a bit confused. The owner's manual says to run 86 or higher (I couldn't find anything in the shop manual), but there's a sticker under the left side cover that says to use 91 RON. I know there's two different ways to measure octane ratings so that might be what has me wondering, but for the time being I think I'll use premium just to be on the safe side.
:2cents:
I hope this helps, good luck.
Big Mac

[Valker]

Octane-run the cheapest gas that doesn't ping. Premium tends to make them run a little ragged after a while (while to me is over 40K miles). Honda mechanics have warned me to NOT store it for any length of time with premium in the system. I have run reg/cheap for 62K miles mostly. I ONLY run premium in high heat (>100º) or in high load situations that cause pinging. The octane posted on the pumps is "pump octane" which needs to be 86 or over.
I live at 3200' altitude in Texas. I have no problems on top of Mt. Evans or Pike's Peak. I have only changed to a K&N air filter.

......now I'm even more confused.

"Honda mechanics have warned me to NOT store it for any length of time with premium in the system"

Hey Valker, did they happen to mention why? And while I have the keyboard out, any idea why the big difference in what the owner's manual says as opposed to what's under the side cover?
:weird:
(*Mac scratches head*)
Big Mac

[Valker]

The difference in numbers between the manual and under side cover is not a difference in requirements, but in names. Pump octane is an average of RON (research octane number) and***...er... the other one (forgot it, sorry). Pump octane is (RON+ ***) divided by 2. Just go by the 86 pump and look at the number on the gas pump-that is pump octane.
He said that the additives in premium gum up the fuel system and deteriorate the rubber seals in the system.
The octane boost in premium actually just slows down the rate of 'flame advance' upon ignition of the mixture. An engine fires (sparks) Before Top Dead Center (BTDC) because it takes some time for the ignition to take place. This makes the most power as final expansion takes place just after TDC. If the fuel fires too fast, there is too much expansion of gases BTDC which results in pinging (aka knocking). The slower flame front of premium cools the flame and makes maximum expansion occur at the proper time. That is why when you add a 'trigger wheel' or timing advance mechanism, you usually have to switch to premium fuel since it causes spark 6º sooner BTDC.
On my old '81 Gold Wing (new in 81-traded in 84 with 100K on it), I was having carb problems-rough running, poor idle. When I asked the mechanic (a great one BTW) about an appointment to check it out, he asked if I was running premium. I said, "Of course". He said, "Quit it". End of problem!:eek:
I hope this relieves a little of the head scratching.

Thanks for clearing that up Valker, I'll run the cheaper fuels from now on and see if I can tell any difference.

If my research is correct, :silly: the missing link is MON (Motor Octane Number). RON+MON/2 was the formula listed at the site I visited.

http://www.seansa4page.com/resource/octane.html

Now that we're about as off topic as I care to be.....class dismissed.
:worship:

Thanks again
Mac

['KC']

Ginzo there is a relatively easy high altitude adjustment that can be made to the carbs. I would suggest that you buy the service manual, soon as you can.
But I live in the Seattle area, around sea level. On the trip to Sipapu N.M. last July I went through Colorado to see my sister both ways, and over Independence Pass. I had no running problems at all, and made no adjustments. You may find that you will have to move up to a slightly higher octane rating in the high altitudes. I didn't, I ran the regular and it worked out fine for me.

Last summer I went on a trip out west with a friend of mine.  He has a BMW K100, and I have a '99IS.  Both of us were hauling sidecars loaded with wives, camping equipment and so on.  In short these vehicles were more like dumptrucks than motorcycles.

Up to some altitude, I think it was around 6,500 ft, I could just drive away from him whenever I wanted: going uphill, downhill, on the flat.  The Valk has so much more power.

But over that altitude the K100 seemed to have more zip.  I attribute this to the fuel injection on the Beemer, rather than carbs on the Valk.  Fuel injection systems constantly adjust mixture.

We were over 9,000 ft pretty often.  The highest point we were at was Monarch Pass (US50) in Colorado.  If I recall correctly that was 12,400 ft.  Somebody from CO correct me if that's not the correct altitude.

All that said, I wouldn't mess with the carbs unless you were going to spend a lot of time at high altitude - say over 6,500 ft.  If you tune for high altitude and then descend to low altitude - say New Orleans at 0 ft, the engine will run very lean. You might burn an exhaust valve.

Peter

ginzo
We are not dealing with a TOP FUEL DRAGSTER it will run fine .I have been all over this USA on my 01 I/S and it RUNS FINE

valker; what part of tx is 3200 feet high?
i must admit, as a long haul trucker, i didn't get to all of texas but i don't think i ever saw anything  higher than a "hill"
are you sure you don't mean 32 feet ?

['KC']

Valker is in Pampa, Tx., now you are on your own as to were in Texas that is. I just know the name of the town where he lives.
Now if I ever get down there again, to see my Sister or my Parents; I'm going to find out just where that is. I couldn't go that far, and not try to see him, and his family.

[Valker]

You are welcome ANYtime.
Pampa is in the panhandle, 20 miles north of I-40, 50 miles east of Amarillo. I didn't say we had hills:) just that we had altitude. We're the high flat place:eek:  Just like the eskimos with snow, we have 27 words for "flat"
Thia HAS to be the prettiest part of the USA....God didn'e even ruin the view with trees!:rolleyes:

Hello Gemini......looking at the Big Bend Brochure......

Alpine, Tx                      4,485 feet
Marathon, Tx                 4,045 feet
Chisos Basin Area, Tx    5,400 feet

Guadalupe Peak of the Guadalupe Mts is the highest point in Texas at 8,749 feet.

been through "armadillo" many times, can't count the times i've run I-40.  hard to believe those elevations digger, but i trust ya:D
if the pan handle is like parts of ok, it must be nice.
still i must say that i haven't found an area more scenic than the pacific northwest (portland,or.) ask kc, he will tell you.
however it is a little wet up here; went riding today and passed three salmon heading up the interstate!:D