Ratio mix for high altitude?

[renotrikeguy]

I recently picked up an 81 250r from my brother in California. Their altitude is about 1000 ft asl. My altitude here in Reno,Nv is 4500 give or take a few 100 feet.

So what I would like to know is, Should I keep mixing the fuel and oil at 20:1 or should I adjust it at all? What about the jet's in the carby?

I just don't want to blow this thing up. Been a long time since I had one and it took my a few years to find one in this good of shape.


Thanks in advance my Trike Piloting Brothers.

[smokinwrench]

Keep mixing your oil the same way 20/1 if thats what you use. Your jetting will have to be changed (more than likely). You will have to do a few plug chops to see where its at.

[Tri-Z Pilot]

Reno, you have it all wrong, altitude does not affetct your mix ratio, (gas to oil) it affects your jetting, (fuel to air) mixture. Also, another thing that you have mixed up, is your belief that your 20to1 mix, is running your bike richer, when in fact, you are more likely to blow it up. You see, it is neither the oil, or the cooling system that keeps the piston cool, it is the gasoline, and since you are running it 20to1, you are actually running the bike leaner than lets say 32to1, or 40to1, get it? The more oil you have in the pre-mix, the less gasoline your engine is receiving, which is what keeps your piston/top end from overheating, and blowing up/seizing. The more oil you have, the less friction, the more gas you have, the cooler your piston runs, so I would say go with like a 32to1 mix, and change your jetting for your altitude.