wr450 carb has changed from earlier year models

I finally decided to do the BKmod and went down to the nut and bolt store and got my stuff and boogied back home and took the carb off and immediately it was quite apparent this carb body is different from the one shown in Garret Bergs outstanding website. Whats different is the little flat tab you drill in to is no longer there. The whole side that the cable cover bolts on to is about a quarter inch narrower because the tab is not there. And I thought to myself weeellll how am I gonna adjust the length of the squirt. Weelll lets see how far off the squirt is first. So I gave the throtle wheel a good spin. And guess what the squirt is perfect. I didnt put a stop watch on it but it looked to be a hair less than half a second. I guess WR 450 owners are gonna have to look elsewhere to cure the bog. I still think mine is running to lean off the bottom and causing my bog. Tim

Try this tip that was posted by TT'er HighPlainsWR.

"All stock 450's have a stumble at the bottom that is the direct result of too much fuel being dumped in to the venturi by the accelerator pump. Under the plastic cover on the right side of the carb there is an adjuster that positions the cam that works the pump. A half turn clockwise will make your 450 a new bike."

I did it and it took care of the stumble right off idle. My bike accelerates hard right off of idle now with no hesitation.

Thanks HighPlainsWR :)


That screw times the start of the squirt so the squirt doesnt splatter on the slide. Mine is timed just perfect. Also the length of squirt is just right 3-4 10ths of a second. I think I really need to richen up my pilot circuit because when you richen up (turn out the pilot screw) it runs best at 3.5 turns out and really has little effect and I believe this is a sign of too lean a pilot circuit. Isnt that so.

I have read that if you are more than two turns out on your pilot screw that you need to go to the next bigger jet.


Yep. I think so to

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