Rejetting for higher altitude?

[Speedthriller]

I'm planning a trip to the French and Italian alps for this summer. Has anybody of you got experience in riding an XS from sea level to an altitude up around 9000ft? Should I take some leaner main jets with me?

 

[XSLeo]

Where I lived in New Maxico I lived at 4300 ft. I had to rejet for that altitude. I also had 12,00 foot mountains close by and often rode up there. I didn't change the jetting to ride up there. It wasn't worth the hassle to change them for an afternoon ride or even a weekend camping trip.
Leo

 

[Speedthriller]

Thanks Leo! I was worried that the mixture would become waaaay to rich at those higher altitudes. Where I live its flat as a pancake. I havent got any experience with riding in the mountains.

 

[TwoManyXS1Bs]

At 9000 ft, the atmospheric pressure is close to 70% of sea level. My Holley carburetor had provision for changing air bleed jets, which is their preferred method of compensation. Holley: "You don't need less fuel, you need more air". I would change the air bleeds for trips to Colorado and Estes Park (over 12,000 ft). Can't do that on the bike, gotta change fuel jets instead...

 

[rowdyrandy]

I moved from Pa to Co and had to rejet - assuming my problems get sorted out I've got a trip planned to around 11,000 this coming weekend. Ill report back on how she runs, my guess (and hope) is not that different

 

[rowdyrandy]

That being said, I will be taking a set of jets with just in case

 

[TwoManyXS1Bs]

And a fresh set of next "hotter" plugs?

 

[retiredgentleman]

I'm planning a trip to the French and Italian alps for this summer. Has anybody of you got experience in riding an XS from sea level to an altitude up around 9000ft? Should I take some leaner main jets with me?

I doubt that you would need to change jets. However, you will lose power from the engine as you increase elevation. IIRC you lose 3% power for every 1000 ft above sea level.

I live at 3400 ft ASL, and take motorcycle trips up to 7200 ft ASL. Even though my bike must be down on power, its not notiable by me. Mikuni carbs seem to handle elevation changes just fine.

I was just in the Alps last year. I drove through the German, Austrian and Italian Alps. The scenery is spectacular. The alps are full of motorcycles. It will be cool at the higher elevations, so take extra clothing and rain gear.

 

[shotgunjoe]

Spare plugs. JIC

 

[5twins]

If you still run the original CV carbs, they are somewhat altitude compensating. They work on engine demand and will only feed the motor what it needs. If the jetting goes a bit rich as the altitude increases, the slides probably won't lift quite as much to compensate. But yes, I would take some smaller jets just in case.

 

[Speedthriller]

Thanks everyone! I think I will take some smaller jets with me, just to be shure.