by JimDirt » Thu Jul 04, 2019 11:52 am
The jetting depends on the elevation and temps you will be riding at , leardriver , our resident carb guru , put this up as a recommendation to use for 450's (X and R) , so I would use it as a baseline to set your jetting , regardless whether you are just buying jets by themselves or using the "jetting kits"
Jetting Guide for Main Jet:(pilot #45 in all cases) CRF450R/X
Sea level....165
2000 ft.......162
4000 ft.......160
6000 ft.......158
8000 ft.......155
Temperature/Elevation:
One main jet size (up/down) for every 2,000 feet or 25 degrees in temp.
You can run this jetting with or without the baffle removed , as I have run my bike with a 05 450R muffler and with the stock baffled muffler (when I am riding a area where noise is a issue) , and it runs good either way , just snappier with the unrestricted muffler , but doing just the top of the airbox area where the snorkel itself is , will be plenty of added air and will help the engine breath much better along with the jetting for the elevation/temps
2020 CRF450R
2006 CRF450X

Weiser , Idaho