carb question

[frizzen]

How much difference does it make if you go to a different altitude? I live at about 4000 feet and plan to go do some riding at 8500. Is it worth the trouble to change the jet in the carb if I am just going to do some forest trail riding? I am on a 2003 arctic cat 500.

[DirtDemon]

Your bike will run a bit richer at that altitude, if it is jetted properly for 4000 feet, then you should be able to get away without re-jetting. Besides, it will likely be colder up there, so that will help offset richening effect of the higher altitude. If you are jetted for sea level, then you may start to see problems at 8500. If you choose not to re-jet, make sure you carry a spare plug in case you foul yours. Also, something to clean a plug with, you can clean and re-use a wet fouled plug. If you have poor performance issues, you can just open up your airbox, just make sure not to let any water get in there when it is opened up. It is pretty easy to change a main, jet even on the trail, you could just bring some extra jets with you and change to a bigger one if you need to. Also, make sure you have a screwdriver to make adjustments to your pilot screw, you will probably need to do that too.

[quadnut20]

How much difference does it make if you go to a different altitude? I live at about 4000 feet and plan to go do some riding at 8500. Is it worth the trouble to change the jet in the carb if I am just going to do some forest trail riding? I am on a 2003 arctic cat 500.

you should be fine !You might feel a slight loss of power but not enough to matter I ride at 8500' and above and my quad is jetted for 5000'

[WillyPoP]

x2 on power loss...however, once you feel the difference, you'll be able to adjust your riding style based on the loss, and adapt.

[GEARHEAD01]

the best way to be safe with your engine in mind is to pull a plug when you are at that altitude after riding a bit and check you plug. do a wot test if you need to be sure. also it usually is the opposite when you ride in the mountains or higher terrain. it is ussually warmer the higher you go. the only difference is less burnable oxygen. it can be harder on your machine if it is to rich.

[DirtDemon]

the best way to be safe with your engine in mind is to pull a plug when you are at that altitude after riding a bit and check you plug. do a wot test if you need to be sure. also it usually is the opposite when you ride in the mountains or higher terrain. it is ussually warmer the higher you go. the only difference is less burnable oxygen. it can be harder on your machine if it is to rich.

It is a fact that the average temperature goes down as you go up in elevation. That is why it snows in the mountains while it is raining in lowlands at the bottom of the mountains. The average temperature drop when going from 5000ft to 8000ft is about 10 degrees. This will mean more dissolved oxygen in the air, which will help offset the affect of the less dense air at the higher altitude. Your motor will still run richer at a higher altitude, but in the winter, when it is alot colder in the mountains, it isn't as bad because of the significantly cooler temps.

[Raptor8]

I cut a 1.5inch by 3 inch hole in the top of my airbox for altitude riding. when you go back down, a single piece of ductape will cover the hole- no rejetting this way. Tip came from Yamaha a few years ago.

Edited January 30, 2011 by Raptor8

[frizzen]

Now that's interesting

[DirtDemon]

Now that is a good idea right there.

[Bimmerdog]

I cut a 1.5inch by 3 inch hole in the top of my airbox for altitude riding. when you go back down, a single piece of ductape will cover the hole- no rejetting this way. Tip came from Yamaha years a few years ago.

I like that idea. Will be giving it a try. Thanks

[GEARHEAD01]

the only down fall with that is if you do any mud or water riding you will fill your box full of water and crap.

[Raptor8]

fortunately I don't have to worry about water- it's woods and high desert here... the nearest water is in the radiator of my truck