1998 YZ400F Carb Question

Hey Guys,

I just joined TT and I already have a question. If this is a question that is answered in the FAQs then I missed it and I am sorry.

I was doing some searching on the net and found a guy who had a 01 YZ 450 for sale and I asked him for the VIN to "look up some parts". He gave it to me and sure as sh*t it was a 1998 YZ 400F.


I did some research and decided I was still interested.

Guy said that it was normally hard to start before he parked it for the Winter this Fall. When he went to sell it this week he couldnt get it to start at all so he reduced the price. I checked it for rough compression and reviewed the bike and decided I was interested. The guy left and I gave it one good hard kick and it fired up and ran for all of 3-4 seconds with a backfire. That is all I can get it to do. It is responsive to throttle but then seems like it is flooding and dying. So it is time to dig in.

I decided that I am going to start with the basics as it was running so recently and go from there. I noticed the carb is leaking everywhere and based on research this starting/running issue is/can be commonly attributable to carb issues.

I tried to download an owners manual and I am having issues. What is the stock carb for this bike? It has a KEIHIN carb stamped with "5BE1 00MA29" ("00's" could be "oo's" as well, not sure yet).;

The guy mentioned that the guy before him raced it so before I order a kit I want to make sure I am ordering the correct one. Also, I am open to recommendations on rebuild kits as well.




Edited by Sburesh

Start with the carburetor, make sure you pull the jets and can see daylight through them, pay close attention to the pilot jet. Make sure to pull the needle seat and replace the o-ring and set your float height. Also, I would double check the valve timing while you have it apart.


You should be able to download a manual here:


Hey man this guy here has an old 98! It’s been my project for a couple years restoring it back to presentable condition. I have the actual service manual so if you need me to look up a section I can. Or look around on eBay I found mine there.

Hey man this guy here has an old 98! It’s been my project for a couple years restoring it back to presentable condition. I have the actual service manual so if you need me to look up a section I can. Or look around on eBay I found mine there.

Also I’m looking into replacing the 98 carb with a newer year so I can take advantage of the leak jet. I’m doing some research on which would be the right one to use and I saw somewhere a ‘05 or newer would work. Just need to get the hot start cables, or as much as you can with it. Let you know what I find out. Lol my bike is literally a conglomeration of many different parts from the newer years bikes. I’ll post a picIMG_0123.JPG

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