Elevation changes/jetting on the trail?

[coyote72]

I was curious what you guys out there do when wheeling up into higher elevations with a carb. I just moved to Colorado and am anxious to go wheeling. The elevation at home is about 6000', and some of the trails out there have peaks in the 11,000' + range. I am running a q-jet, so changing jets and metering rods is not the easiest thing to do on the trail, but will be done if needed. What are some of the things you guys do?

[DirtyLarry]

I dealt with that for years. No matter what you do carburetors just don’t work well at high altitude. I gave up and went to fuel injection. Problem solved.

[72freak]

Originally Posted by DirtyLarry

I dealt with that for years. No matter what you do carburetors just don’t work well at high altitude. I gave up and went to fuel injection. Problem solved.

Yep!

['63GENIII]

FI or diesel. Carbs are a pain for elevation changes. I ran up to Street Vibrations one year on the bike and had to change jets 4 times in 6 hours. Im all about the FI these days!

[STOCKISH]

Run it on propane.

[Zoomad75]

While I agree, FI is the way to eliminate the problem, I've had decent luck with my q-jet. However I don't fool around with changing rods/jets on trail. From my home altitude of 4800ft to 13,000ft all I've done is give a little bump in timing and couple hundered rpm increase in idle speed and it putts right along.

The thing is crawling along on the trail I'm not running WOT or even 1/2 throttle so making major changes in the rods/jets really wouldn't have an impact. The minor bump in timing is really more an improvement that I can feel. I just snug the dist clamp enough to hold it, but still allow a little movement if you bump it with the palm of your hand.

[coyote72]

Originally Posted by Zoomad75

While I agree, FI is the way to eliminate the problem, I've had decent luck with my q-jet. However I don't fool around with changing rods/jets on trail. From my home altitude of 4800ft to 13,000ft all I've done is give a little bump in timing and couple hundered rpm increase in idle speed and it putts right along.

The thing is crawling along on the trail I'm not running WOT or even 1/2 throttle so making major changes in the rods/jets really wouldn't have an impact. The minor bump in timing is really more an improvement that I can feel. I just snug the dist clamp enough to hold it, but still allow a little movement if you bump it with the palm of your hand.

Thanks for the feedback. I am still in the process of dialing it in from sea level. I think I may try a lighter power piston spring. I see you are from CO as well, we will have to get together for a wheeling trip!

[Zoomad75]

Originally Posted by coyote72

Thanks for the feedback. I am still in the process of dialing it in from sea level. I think I may try a lighter power piston spring. I see you are from CO as well, we will have to get together for a wheeling trip!

Once you get it set up for your home altitude, climbing up from there shouldn't be too much of a problem. Remember we got less air up here, so have to go leaner on the mixture. It will need more timing than at sea level. Get it set so it's running good at home and then give it that little bump in timing when you are up in the mountains if you need it.

Not sure the next run is, but probably it will be in the snow when we get some. DirtyLarry and I are south of you in Pueblo, but that's not all that far and there's some good trails not too far from all of us.