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tips for high altitude riding?
Posted: Wed Jul 16, 2003 12:52 pm
by Michael Schaefer
Hi all,
My KLR is setup perfect for this flatlander country here in Dallas.
But I'm gonna be up in Colorado in a week riding the high passes up
there. My altitude will vary from 5,800 to 13,100 along the route.
I'm wondering if anyone has any tips for setting the bike up for this
kind of riding. Specifically, I'm wondering about carb setup. I'm
using the stock carb with stock needles. My pilot screw is currently
turned about 1 and a half turns out.
Thanks in advance for the info,
Michael
tips for high altitude riding?
Posted: Wed Jul 16, 2003 1:14 pm
by daylan
Tips for High Altitue Riding....
Don't fall down
Cheers
tips for high altitude riding?
Posted: Wed Jul 16, 2003 2:31 pm
by Fireman Ed
> Tips for High Altitue Riding....
>
> Don't fall down
>
I second that one, and watch out for turkeys in the fog. the crash
hurts just as bad at 6,000 feet as it does at sea level.
Fireman Ed
A17---still crooked
tips for high altitude riding?
Posted: Wed Jul 16, 2003 2:33 pm
by pete88chester
What you are going to find is that your bike will be running richer
at the higher altitudes of Colorado compared to Dallas. This is
because the higher you go in altitude the less dense is the air.
This is because air has weight & the air at lower altitudes l is
compressed by the weight of the air above it. The less dense high
altitude air will have fewer molecules of nitrogen, oxygen, co2, etc.
per volume than the more dense air at lower altitudes. The thing is
that carbs do not compensate for the less dense volume of air flowing
through them (there were some, there was a Solex carb used on some
Merc. Benz cars that had a main jet altitude compensation), they
basically meter out the same amount of fuel per volume at high
altitudes as at lower altitudes. So a carb jetted correctly for sea
level that is run at higher altitude will mix the same amount of gas
to the less dense air which gives you a rich mixture, same amount of
gas for less oxygen to combined with. I remember the first time I
drove my Pinto to the top of a high mountain & it idled like the
choke was stuck on & had low power. The opposite happened when I
drove to considerable lower altitude, the engine felt stronger (which
indicated it wasn't jetted right for the altitude I lived at). The
problem for somebody that lives at a very high altitude that re-jets
their carb for that altitude & then goes to sea level, the carb is
extremely lean. If they run the vehicle at high speed using high
power they could cause engine damage like piston seizing or burning a
hole in the piston. Any way back to your question: I do not think
you will have much trouble. My A16 has the stock jetting & I have
run it at altitudes of 3000 ft. to 10500 ft. with no real problems.
Re-jetting it when you get out here may help, but would it be worth
it? Considering how lean Kawi sets the carbs to meet air pollution
standards it may actually be running better at some higher altitudes.
Another thing to consider is temperature. The colder you go the
richer the mixture may need to be. A carb jetted correctly for say
5000 ft. & temperatures in the high 90's may not need re-jetting when
run at 8000 ft. & temperatures of mid 70's. I found this when taking
my road race bike from the Denver area tracks to the race we used to
have at Steamboat Springs, CO in the fall.
This brings me to another point I have been meaning to comment on.
The flat statement that the idle mixture screw should be set to 2
turns out. That may be true for a bike operated at sea level, but
may not apply at higher elevations. You need to adjust the mixture
screw to get the best idle & transfer to the needle part of the
throttle position for your bike according to where you live.
Well I was long winded again, sorry. Pete Chester A16
tips for high altitude riding?
Posted: Wed Jul 16, 2003 2:53 pm
by Michael Schaefer
Good info Pete. That's along the lines of what I was looking for. So
the bike is gonna run rich. So if I need to lean it out a bit, do I
close (clockwise turns) the pilot screw or open (counterclockwise) it?
I'm looking for an explanation of what that little pilot screw is
doing in there so I can figure this stuff out on my own next time.
Thanks,
Michael
--- In
DSN_klr650@yahoogroups.com, "pete88chester"
wrote:
[snip]
> This brings me to another point I have been meaning to comment on.
> The flat statement that the idle mixture screw should be set to 2
> turns out. That may be true for a bike operated at sea level, but
> may not apply at higher elevations. You need to adjust the mixture
> screw to get the best idle & transfer to the needle part of the
> throttle position for your bike according to where you live.
>
> Well I was long winded again, sorry. Pete Chester A16
tips for high altitude riding?
Posted: Wed Jul 16, 2003 3:25 pm
by Judson D. Jones
Leave your carb alone. The vacuum slide carb on your KLR will pretty
well compensate for the altitude at everything but an idle (just like
the Solex that Pete Chester mentioned). Your idle mixture is already
set fairly lean. You will notice some power loss due to the reduced
air density at altitude, but your mixture will be OK.
--- In
DSN_klr650@yahoogroups.com, "Michael Schaefer"
wrote:
> Good info Pete. That's along the lines of what I was looking for.
So
> the bike is gonna run rich. So if I need to lean it out a bit, do I
> close (clockwise turns) the pilot screw or open (counterclockwise)
it?
>
> I'm looking for an explanation of what that little pilot screw is
> doing in there so I can figure this stuff out on my own next time.
>
> Thanks,
>
> Michael
>
> --- In
DSN_klr650@yahoogroups.com, "pete88chester"
> wrote:
> [snip]
> > This brings me to another point I have been meaning to comment
on.
> > The flat statement that the idle mixture screw should be set to 2
> > turns out. That may be true for a bike operated at sea level,
but
> > may not apply at higher elevations. You need to adjust the
mixture
> > screw to get the best idle & transfer to the needle part of the
> > throttle position for your bike according to where you live.
> >
> > Well I was long winded again, sorry. Pete Chester A16
tips for high altitude riding?
Posted: Wed Jul 16, 2003 3:35 pm
by Arden Kysely
I'll second Jud's post. I was up over 10,000 feet in Utah last June
and the bike ran fine. You may find you don't need to choke it as
much (if at all) to start it, since it will already be running rich.
__Arden
--- In
DSN_klr650@yahoogroups.com, "Judson D. Jones"
wrote:
> Leave your carb alone. The vacuum slide carb on your KLR will
pretty
> well compensate for the altitude at everything but an idle (just
like
> the Solex that Pete Chester mentioned). Your idle mixture is
already
> set fairly lean. You will notice some power loss due to the reduced
> air density at altitude, but your mixture will be OK.
>
> --- In
DSN_klr650@yahoogroups.com, "Michael Schaefer"
> wrote:
> > Good info Pete. That's along the lines of what I was looking for.
> So
> > the bike is gonna run rich. So if I need to lean it out a bit, do
I
> > close (clockwise turns) the pilot screw or open
(counterclockwise)
> it?
> >
> > I'm looking for an explanation of what that little pilot screw is
> > doing in there so I can figure this stuff out on my own next time.
> >
> > Thanks,
> >
> > Michael
> >
> > --- In
DSN_klr650@yahoogroups.com, "pete88chester"
> > wrote:
> > [snip]
> > > This brings me to another point I have been meaning to comment
> on.
> > > The flat statement that the idle mixture screw should be set to
2
> > > turns out. That may be true for a bike operated at sea level,
> but
> > > may not apply at higher elevations. You need to adjust the
> mixture
> > > screw to get the best idle & transfer to the needle part of the
> > > throttle position for your bike according to where you live.
> > >
> > > Well I was long winded again, sorry. Pete Chester A16
tips for high altitude riding?
Posted: Wed Jul 16, 2003 10:04 pm
by kdxkawboy@aol.com
In a message dated 2003-07-16 10:55:26 AM Pacific Daylight Time,
strathound@... writes:
>
> My KLR is setup perfect for this flatlander country here in Dallas.
> But I'm gonna be up in Colorado in a week riding the high passes up
> there. My altitude will vary from 5,800 to 13,100 along the route.
> I'm wondering if anyone has any tips for setting the bike up for this
> kind of riding. Specifically, I'm wondering about carb setup. I'm
> using the stock carb with stock needles. My pilot screw is currently
> turned about 1 and a half turns out.
>
> Thanks in advance for the info,
>
>
The KLR parts fiche calls out the high altitude jetting for the KLR.
According to the shop manual you should run this jetting if you are above 3000'. I
live at 4700' valley and do most of my riding between 6000' and 10,000'. I am
running the Dynojet kit. They call out a 136 (their sizing not Kehin's) as the
equivalent for Kawasaki's high altitude setting. For my riding I've found the
bike runs best at those altitudes dripping the main jet another size and putting
the needle jet clip on the 4th or 5th notch from the top - I can tell the
right setting because it stops the muffler backfire 'poof' I get only when
turning the engine off.
There is something else to cover that don't deal with the bike. It doesn't
sound like you are used to spending time at high altitudes. Do not be surprised
if you start feeling light headed, or a bit dizzy. Its just your body reacting
to the O2 being thinner. Common name for it is altitude sickness. From a pure
biomechanics POV, you autonomous nervous system has to learn to tell your
lungs to take deeper breaths to draw in enough volume to satisfy your oxygen
needs. Its one of those quirky things that defy any means of predicting who, or
when it will hit. All that can be said is it can happen to folks as they get
above 6000'.
Pat
G'ville, Nv
[Non-text portions of this message have been removed]
tips for high altitude riding?
Posted: Thu Jul 17, 2003 12:00 am
by Randy.Hoskins@worldnet.att.net
Michael,
Don't worry about messing with the carb. Stock KLR's have been riden to
over 17,300 ft (been there, done that) without messing with the carbs.
There is some loss of power, but as noted by some of the other listers
your body is losing a lot more than the bike.
I once did a head to head race with another KLR at approximately 15,000
ft. His bike had been setup for high altitude operation. He had
drilled his air box and changed his jetting. My KLR was pure stock. My
top speed was 75 mph. He could do 85 mph. From a practical standpoint
however, it didn't make much difference. There aren't that many places
in Tibet where you can ride 85 mph. Under normal trail riding, I had
plenty of power.
It is also important to note, however, that after we dropped from the
last 17,000 ft pass to lower elevations, his bike was hardly running
(top speed 25 mph) until he rejetted his bike. Mine was still running
strong.
Randy
A13
Michael Schaefer wrote:
>
> Hi all,
>
> My KLR is setup perfect for this flatlander country here in Dallas.
> But I'm gonna be up in Colorado in a week riding the high passes up
> there. My altitude will vary from 5,800 to 13,100 along the route.
> I'm wondering if anyone has any tips for setting the bike up for this
> kind of riding. Specifically, I'm wondering about carb setup. I'm
> using the stock carb with stock needles. My pilot screw is currently
> turned about 1 and a half turns out.
>
> Thanks in advance for the info,
>
>
tips for high altitude riding?
Posted: Thu Jul 17, 2003 7:00 am
by Mark Sampson
I agree------to do absolutely nothing to your KLR to ride high altitudes.
It will do fine----the idle will drop and the power will drop----but it will
do fine. And when you come back down-----you can do nothing again, as it
will run fine !!!!
I've stood and watched guys diddle with jetting several times on the road
and trail while I just stood and watched.
Have a clean air filter tho.
Mark Sampson
www.bigdogadventures.com