altitude adjustments

I'm planning a trip to Cloudcroft, New Mexico with my family. We live in Texas and Cloudcroft is about 9000ft. WR400, TTR125, and (2) PW80's. I'm concerned about performance if no adjustments are made. I am not interested in messing with the timing. I would like not to rejet if poss. Will a needle adjustment do the trick (at what possition?)Are the 400 and 125 (4 stroke)as effected by altitude as the 2 stroke. If adjustments are necessary, I'd like to try and do this my self. Any simple advice is appreciated.


I am from Ft Worth, and just got back from riding in Utah (up in the 6000 to 7000 ft altitude). My buddy came over from CA to ride with me on his YZ400 also. He called the dealer and asked the same question about jetting the bike for altitude. They said two strokes would be more affected than 4's would. After 140 miles of serious off-road riding in two days the bikes (98 WR400, 99 YZ400) ran flawlessly at altitude.


Are you saying you made no adjustments for altitude? Can I make only minor adj. for the pw80's and still have fun?


While I would generally agree that two strokes are more affected by altitude, an 8,000 foot difference is pretty extreme and trust me, you will notice it, especially on your WR. But if your bike is jetted stock but uncorked exhaust and no air box lid you may not, because in that state it is going to be pretty lean.

My YZ at that elevation was ok with a 40 pilot and clip # 3, but still a little too rich. I wouldn’t worry about the main unless you have one handy, but if you put a 40 pilot in there and drop your needle a clip or two you will be glad you did.

Where are you going to ride? A few friends of mine are planning a trip up next wknd (8/12). I’ve not ridden the area, but there are supposed to be some good trails in the Sacramentos SE of town.

Have fun, hope this helps, and when you get here, welcome to NM! We don’t hate Texans anymore now that the Californians are here :)


Yes, that is what I am saying, zero adjustments on the WR and the YZ. Just started them up and rode. They ran pefectly.

I moved down here to the DFW area from Utah (5000 ft) and brought a JR50 (injected 2-stroke) and really have not done anything with it but let the kids ride/race (TCCRA) it. I am not sure about the PW80 and how it works. Sorry not much help there.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now