WR400 with YZ450 2008 carb

Hi all.

I just bought an old 1999 wr400 that had some idle issues. Bought a JD kit for it. But instead of fiddling with the old carb to get it right I decided to go for a newer carb since that seams to be recommended. So a couple a weeks ago I purchased a YZ450 carb with throttle and cables plus the remote hot start. Every thing bolted on well enough. (I have left the old 1999 separate from the carb hot start on, but dont use it) The problem now is that the will start at all. It started easy enough with the old carb and it still has a spark. But for some reason it will not run. Tried with new plugs. The carb looked clean when checking it, but I have reopened and cleaned it and all jets with carb clean and blew through the jets with compressed air just to be safe. No change. I don't know if the jetting for new carb is stock. Can anyone that have done a similar swap give some pointers on the jetting changes they have done?



Well, you've got to let us know what jets you have first. I know it's a pain in the butt, but your going to need to tear into that carb and find out what jets are in there, then we can give you some advice.

are any jets clogged on the new carb? did you try spraying some ether in there to check ?

Thanks for replying!


I am getting quite good at getting the carb in, thorn down then in again :thumbsup: I have ordered a rebuild kit for the new carb that comes with everything. That way I know what my setup is and are sure that all jets are stock. Gone take a week to get to Norway though :cry:


All the jets look fine but I have sprayed them with carb cleaner and blown through them with compressed air.

My guess is that some of the jets are to fare off.....

Try 165/48 jets. What's in there now?

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