I have been working on my 2005 WR450 way longer into the riding season than I would like to. I have a problem with the bike running without the choke on. I have totally rebuilt the top end, to include valve adjustment and new rings. The bike will just not run without the choke on. I have fiddle-farted with the Air/Fuel and Idle adjustments so much I fear that I will wear out the threads!! When I do ride the bike with the full choke on, it has extremely choppy throttle response. I turn off the choke and it cuts out. It appears the vacuum lines are correct. It starts, so I know I have spark. I have cleaned the carb so many times I feel like I am the Bo and Luke Duke of the 450 world. There has go to be an answer, but I'm at a loss.
Posted July 04, 2016 - 07:21 AM
Ream the passage above the pilot jet with real carb cleaner and light wire or fishing line
There is a tight bend in there that gathers corrosion and debris
Also, service the hot start plunger and cavity for corrosion/leaks
When you say you 'cleaned' the carb, unless you also replace the worn out areas, cleanliness won't help much
Posted July 04, 2016 - 08:53 PM
If you have the stock WR exahust tip, it will never, ever run correctly.