I am a new WR450 owner doing the free mods. I am not a mechanic! In the process of swapping a JD needle for the stock needle, I raised the carburetor slide "to the top" for easier access to the needle. When I did this, the top of the throttle valve came up over the top of the carburetor housing and froze. It will not drop back into place and the throttle movement has no effect. When I checked the throttle stop, I found that it was missing. I am assuming that because of this, the throttle valve opened up more than it should have, causing the problem. Any advice on how to get my carburetor back together would be appreciated. Thank you. Cairn Solution: Turning the throttle enough to free up the "push rod link lever assembly," then pushing the lever, frees up the throttle valve. The valve may not drop, however, if the jet needle is not aligned properly. Finally, the throttle valve lever rollers need to be aligned with the slits in the throttle valve, which is as straigtforward as it sounds. My thanks to PNWWR400 for coaching me through this process.