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04 CRF450R high altitude jetting
Posted: Mon Dec 06, 2010 8:46 pm
by bffbmcslc
I bought an 04 CRF450R from my brother who lives in California. I live in Salt Lake City, Utah. It Has a White Brothers exhaust, other than that stock. What carb jetting do I use for the higher elevation. (5000 ft.) It runs pretty rough up here and he said it ran great at sea level.
Posted: Tue Dec 07, 2010 6:17 am
by 450xdirt
45 Pilot
165 Main
JD red needle 4th from top
fuel screw 1 1/2 to 2 out.
This has been working great for me. 4500-9500 ft.
Posted: Sun Dec 26, 2010 8:11 am
by Leardriver
These bikes are pretty forgiving of imprecise jetting. I have dyno'd CRF 450's in Denver at 5700 feet, and actually measuring the A/F ratio is a valuable tool.
165 for sea level
162 for 2000 feet
160 for 4000 feet
158 for 6000 feet.
That will put your bike at 12.8 to 13-1 A/F ratio. Even if you are off by 2 jet sizes, your bike will run ok. The difference between running a 172 versus the correct 158 at 6,000 feet is a whopping two horsepower. More than that $500 pipe will give you!
Posted: Sat Jun 02, 2012 11:09 pm
by scrumplar
I have a 08 450r - live in Denver, ride at 5500-8000 ft.
my bike continues to rev when coming to a stop or on the low speed deceleration..Idle is set ok after it settles but it has the symtom of a high idle.
running 162MJ and 72??
have not checked needle clip location..
is this air / fuel mixture related..
Posted: Sun Jun 03, 2012 8:16 pm
by motosicko
scrumplar wrote:I have a 08 450r - live in Denver, ride at 5500-8000 ft.
my bike continues to rev when coming to a stop or on the low speed deceleration..Idle is set ok after it settles but it has the symtom of a high idle.
running 162MJ and 72??
have not checked needle clip location..
is this air / fuel mixture related..
I have an 08 in Denver also. 160 main, 45 pilot, 2nd clip position down on needle. Runs like a champ. I hope you're not saying you have a 72 pilot. If so, that is way rich and would be causing bad idle problems.
Posted: Mon Jun 04, 2012 3:03 pm
by Leardriver
That sounds like a hanging idle, which indicates a slightly lean pilot circuit. Try a 45 pilot at 1.75 turns out, and it will probably be perfect.
A slightly plugged pilot will give you the symptoms you describe also. It flows enough to run, but is lean. Cleaning them is an exercise in frustration, and screwing in a new $6 pilot works very well.