Adjusting for above sealevel
#1
I just checked out my elevation on a topo. map and it's saying that my elevation is between 1500-2500. What adjustments(if any) should I make to the carburator. I am putting a Big Gun exhaust on my Raptor it is calling for 150 and 155 jets with 27.5 pilots. I also have a ign. advance key(if that has any affect). Let me know....
#2
That's a pretty broad ballpark figure for elev. I would contact your town engineer's office or the equivalent for a more specific elev, or if you know someone with a gps they could tell you exactly.
As to the main question, as I frequently tell people, the only real answer to YOUR jetting is YOUR engine, so I'd try the recommended jets you mention and run a test/plug read. If it indicates a rich condition the go to one size leaner jets. I don't know what elev Big Gun bases their recommendation on, but I'd have to assume it was on sea level. If so you'll possibly be a tad rich, but no problem there. Lean is where a problem can occur.
A rule of thumb is that a jet change is needed for each 1000-1200' of elev., but that is based on no air flow additions so the bottom line is...test and read the plug.
As to the main question, as I frequently tell people, the only real answer to YOUR jetting is YOUR engine, so I'd try the recommended jets you mention and run a test/plug read. If it indicates a rich condition the go to one size leaner jets. I don't know what elev Big Gun bases their recommendation on, but I'd have to assume it was on sea level. If so you'll possibly be a tad rich, but no problem there. Lean is where a problem can occur.
A rule of thumb is that a jet change is needed for each 1000-1200' of elev., but that is based on no air flow additions so the bottom line is...test and read the plug.
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