High altitude Carburation-High CR Pistons?

[zorpman]

Hi All,
1981 xs650. Am moving from sea level to 6500'. Bike will not be used below 5000'. Thinking that adding high compression pistons (say 10.5-11.00) will help squeeze in more oxygen molecules in the thin air at 6500' (poor mans supercharging). I can lean out the carbs to get the right mixture of available oxygen to fuel.

Any suggestions on my plan?

What is the current preferred carb system with pods? I figure about 34-36mm as I might add a 750cc top end and maybe go with re-phasing. Am looking for mid-range, not high RPM, good starting, smooth running.


Anybody have any ideas?

 

[retiredgentleman]

I drive my bike at elevations as high as 7200 feet ASL, and my Mikuni BS38 carbs run just fine. My carbs are tuned for my normal elvation which is 3400 feet ASL.

Once you move to 6500, retune the carbs using "dead cylinder" method,and a re-sync as well.

There's many different carbs used by the lads on this site (mostly using pods). I'm sure each one will tell you that their carb choice is the preferred one to use

Keep away from the PWK performance carbs that Mikesxs sells, as they have been plenty of trouble.

I believe CV carbs are known to work better at changing altitudes, versus non CV carbs.