Altitude adjustments & taller windscreen?

[divide wee]

A little background.

I just bought a 2006 Gs500 F for my wife's first bike. Took it out for a spin this afternoon and found it to be a little weaker than I thought it would be. The bike only has 1200 miles and was originaly bought in Denver (elevation 5200'), but I live and ride in the mountains at 9000'. This little guy is only 150 cc's smaller than my 650 V-Strom but is down on power a bunch. I've only put about 30 miles on it so far and plan on pulling a plug after a few more to see how it is burning. Any advise on jeting at this altitude?  I had a tough time getting any acceleration from 65 - 70 mph even down a few gears and spinning at 7000 rpm. I do weigh 250 lb and may be just expecting too much. Any feedback is appreciated.

Also, how much extra protection do the taller windscreens provide? I'm thinking a taller windscreen, grip puppies and up and back handlebar risers or new taller bars will help make this bike fit Linda's needs a little beter.

Oh! I was plesently supprised at how much fun this little bike is in the twisties this afternoon.

Thanks,
Mike

[trumpetguy]

Here's a link to some general jetting info:
http://www.motorcyclecarbs.com/carbs101.pdf

Compared to sea level, you would need a MUCH smaller jet at 10,000 feet.  For example, a 125 main jet (I have an older GS -- the newer ones use a different carb) at sea level would go to a 112.5 jet at 10,000 feet, using the 0.9 conversion factor from the website above.  You need to find out what is in there now (was it re-jetted for Denver?) and go from there.  You will get a little more power and better mileage if you're not running so rich.

The other issue is comparing it to a V-Strom.  It's apples and oranges -- the GS is a two valve per cylinder air-cooled, old technology engine.  Reliable and simple, but not nearly as efficient.  Compare the power of a Ninja 500 (4 valves, water cooled) to your GS.  And they're the same engine size.   So the V-Strom is in a different league.

As you have discovered, the GS is fun in the twisties.  It's just not going to win any stoplight races against larger, newer bikes.   

[gsJack]

SV650 ('04)  73.5 @ 8750  47.1 @ 7250  11.87 @ 110.0

GS500E ('01)  39.2 @ 8500  26.6 @ 7000  13.65 @ 95.5

Like Trumpet sez, the GS500 has an ageing 70's design 2 valve engine while the SV has a modern one.  Look at the HP, torque, and quarter mile figeres above for the 2 bikes!

The GS500 has never been happy at less than 3-4k rpm, it's necessary to keep it above that just to keep it moving,     If your an experienced rider, try keeping it between 7-9k rpm while running in the mountains.  Stock it runs a quick pace at those speeds.

My old 97 GS was about as lean a bike could be and I didn't notice any performance change at 6-6500' in the Smoky Mtns and I live in NE Ohio at about 500' elevation.  Our eastern mtns just don't come any taller than that.     You may just have to get used to running a GS500 at pace to get the most out of it.



jp and me a few years ago.

[divide wee]

I did realize that the engines were at least 2 decades apart in tecnology but the V-Strom is taller and heavier.

As I was riding the GS yesterday, I was thinking gack to my old 76 CB 500 which in my memory was quicker. This very well could be selective memory at its best.

When I have a few more miles on the little girl, I'll pull a plug and check the mixture.

Thanks,

Mike