Help Needed Jetting on '03 WR450...
Posted May 24, 2005 - 01:29 AM
He busted his head pipe and replaced it with an FMF Powerbomb SX, the stock silencer has been uncorked, stock air filter, airbox baffle has been removed, and he's racing at elevations of 800' - 2000'. The jetting was stock until I installed a 165 main jet which helped a bunch.
My questions are: Can you just buy a single JD needle? Looking at the database I probably need a Blue or Red one. What all comes in the JD kit? He really doesn't have $65 to spend. I'm not familair with the starter jets or leak jets, where can I find a diaghram showing their location in the carb? What are the stock sizes on the leak jet and the starter jets? Where can I buy them? Local dealer had never heard of them. Where can I find a list and "how to " do all the free mods? Found a great site for the WR250 but not much on the 450.
Thanks to all for the info you have already provided and any advice you can provide.
Posted May 24, 2005 - 05:55 AM
If it starts fine, leave the starter jet alone.
The leak jet is in the bottom of the float bowl and can be had from Sudco...they call it the Accelerator Pump jet. Diagrams can be had on the Yamaha parts site.
The JD kit comes complete with two needles, main jets and instructions. The needles are not sold separately.
There you have it...SC
Posted May 24, 2005 - 06:15 AM
Posted May 24, 2005 - 12:59 PM
ThumperFAQ also applies to the 450, though it is geared towards the 250. A 165 sounds a bit lean for that elevation, especially since you've opened up the pipe and airbox. What size is your pilot jet?
The pilot jet is a 45 (stock). I'm trying to come up with a 48 pilot and a 168 main locally. The shops around here just don't carry many jets. Will probably have to order.
Posted May 25, 2005 - 01:15 AM
If not, I'll look for the needle the Mountainman refered to from a '04 WR.