Son's 2004 WR450

I am about to jump in and help him rejet his bike back to low altitude specs. When the bike was purchased new we put in a dynojet kit and set it to the recommended specs for the altitude ridden. The butt plug was removed and the air box drilled for more air along with an aftermarket air filter installed. A year ago a hot shot exhaust cam was installed for more top end. I would like to unlock the potential of the FCR carb. I have never really felt it was tuned properly. What are some simple fixes to help the problem ? What are more technical fixes if we get ambitious ?

I would believe a JD jetting kit is what you are after :p


good luck

at least you have the steel frame. making jetting easy :lol:


My bike is jetted perfectly, no need for JD. those kits are over rated.

With stock pipe, and buttplug removed, low altitiude (0ft up to 8500ft) i have:

165 Main

45 Pilot

72 Starter

40 Leak

#4 stock needle

70 Pilot air

Also, the AP spring, and AP diaphram rivot has been tweaked and timing adjusted for a fat spray when throttle is opened fast. This is crucial for the FCR.

It has always had a flat spot when rolling on the throttle before and after the DJ kit. Would one of those bolt on quick shots help the situation ?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now