Carbureted ATV at 9-11K elevation

[jyoung1901]

Doing an archery hunt with two friends in CO this year and bringing a couple of ATVs. One of them is EFI so not worried about it, but the other has a carburetor and runs great here in TN at 600 ft. For those of you who take carbureted ATVs from flatlander areas, how does it run? obviously down on power but really just need it to get one person up and down the hills to get to the trailheads and such. Have you had any problems with them running too lean and hot and needing to adjust any of the jets or anything?

Thanks in advance!

 

[PathFinder]

Used to ride my old Fourtrax 300 from 5500 to 11k above my house all the time. Definitely short on power at 11k, but runs just fine. Four stroke ATVs aren't nearly as picky as 2 stroke dirt bikes. You'll be just fine.

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[Randle]

I took my Kodiak 450 from 2400 ft to 12k it ran ok but I did come home and rejet for 6k , then sold and bought 700 EFI grizz. Never did take the rejetted 450 back up to 12k

 

[SDHNTR]

Do it with mine every year from the beach to 8-10k. I just have to turn the idle up a bit. No real issues.

 

[Wapiti1]

Depending on the style of carb you have, you can move the needle down one position to lean it out. They run rich at high elevation. As noted above, on a 4 stroke it just gets really doggy, on a 2 stroke they foul plugs constantly.

Moving the needle is a good temp move to get it to run better. If you are there a lot, rejet the carb.

Jeremy

 

[Jonny360]

I've got my dirtbike jetted for 6k and I ride 4k-12k. Runs great.

 

[Elkdreamer]

Mine would hardly run at 7k but I live at 800 ft. I had to rejet but had another underlying issue. You can always take the air box lid off to help some. It will pull extra air and help lean it out some.

 

[browning2480]

Have taken mine from Arkansas to 10-12k feet many times. Lower on power but I am a putter anyway, so no real issues. I don’t notice it unless I try to mash the gas and then it Boggs down. You have to feather it but runs fine.

 

[Beendare]

I've got a 06 Honda Rancher I run around on every year at 11,000'. A little less power is all, just keep good fresh fuel in it....which is a challenge.

 

[Smokeslider]

The need to rejet will be dependent on the make and model of ATV and carb. With that said, If it were I, I would have some jets and tools with me to change out if I found some diminished performance beyond what I was willing to accept.

Reminder- When you gain elevation, you need to decrease jet size. The machine isn't going to lean out going up, it will richen. So besides lower performance, you might run into issues with fouling plugs. If you do rejet for higher elevation, don't forget to reset back to current settings prior to using the atv back home.

 

[cnelk]

If that carburetor is a Mikuni it takes about 90 seconds to rejet it

 

[Blockcaver]

I had an Arctic Cat 400 that wouldn't pull steep grades above treeline in CO, (>11,500' elev) even when I re-jetted it for 10,000'. Too heavy for the HP an clutching it had. Sold it to a friend that lived at 6,000' and he still uses it 11 yrs later...re-jetted for 5,000'.

My Honda Rancher 350 5 speed and Rubicon 500 squash plate automatic ran better after re-jetting for 10,000' but were OK with jets for 5,000'. Just a touch rich. Never tried them with sea-level jets until I moved to BC.

As mentioned, you won't ruin an engine running them too rich but you'll fry one if you run it too lean. I sold a Honda 250 Trials bike jetted for 8,000' to a friend that took it to the low deserts in AZ. Fried the engine in less than an hour. He knew better but ran it anyway.

 

[Marble]

Do it with mine every year from the beach to 8-10k. I just have to turn the idle up a bit. No real issues.

This

 

[WMag338]

I read an easy way would be to drill some small holes in the airbox and put plugs in them when at home. When at elevation, pop the plugs out and go. Have not tried myself, but sounds like a good idea to me.

 

[4ester]

15 years ago we took some old carbureted machines to Colorado from PA. We had lots of trouble, some wouldn’t stay running, some we had hell starting. I’d change the jets or at least have the right ones along.

Also be prepared for some dust in your air filter. Pretty dry right now.


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[Blockcaver]

I certainly would not drill holes in the air filter box that let outside unfiltered air directly into the carburetor/engine You can dust an engine very quickly in dusty conditions.

 

[El Gavilan]

I take a couple of 2008 Honda Foreman 500 Atv's from 300' to 9200' every year with no problems at all. A slight idle adjustment is normal but they run great up there.

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[jyoung1901]

Thanks for the replies. Its a suzuki king quad 300 and hopefully will just be able to adjust the idle, i may pick up a coup of leaner jets just in case. I use to play with the jetting on a 400ex all the time so hopefully similar.

Thanks for the input! trying to think of everything i can to prepare to give us the best chance of getting on some elk! Thanks!!!