Somone please HELP!! :/

So yesterday I ended up going to pick up this guy's 2002 YZ426F off of craigslist.

I get there and I was shocked by how clean the engine was, the plastics, and the entire bike looked like it had hardly been ridden like he described... He fired up the bike and it fired right up first kick but would unfortunately die if the choke was not out all the way and the bike way not revved up..

So I figured (as he described) it would be an easy carb clean. Went to Del Amo motorsports and got a few new parts to throw on the bike while I had it apart, new pro taper handle bars, grips etc..

I get home and change the oil (which looked brand new) replaced the air filter, replaced the coolant, etc.. Finally I get to the carburetor.

I take out all the jets except the "Pilot air jet" and "Main air jet" these were not well pictured as to their location on the manual. They ended up being hidden in the main boot so I removed that and was very sad to find this picture...

Uploaded with

The jet on the left is the "Pilot air jet" which help regulate the bikes idling. This would not turn or budge AT ALL. I tried sawing the crevice down so I could turn it with a flat head and the brass just broke off (no way it is coming off now).. (it is actually worse now then the picture shows) Most of the metal surrounding the jet has fallen off so 75% of the jet is now exposed although it is certainly not going anywhere.

Hopefully you guys can get an idea of what im dealing with here and offer some keen advice as to a remedy..



maybe hit it with a tiny bit of heat then let it cool down, Ton PB Blaster and let it soak overnight then an easy-out? that's my usual routine anyway.

^X2 on what he said also take a dremel with a cutoff wheel and cut a new deep groove to get a good bite with a Flathead screw driver. I ran into the same issue once working on an xr250 carb.

i dont know where in ca you are but when i broke my yz 400 carb i called rancho motorcycle dismantling and they had one from a 426, i think he quoted me either $60 or $120 for it but you could call and find out.

the website is

You if then PB Blaster and easy out don't work, you might call around and see if you can find someone to "EDM" it out (Elctro-discharge machining..or something like that) I had to have that done to a fork leg pinch bolt once when an easy out broke off...not too expensive, and they burn out the workpiece without damage tot he threads. Pretty trick...

I still have the stock carb on my 2001 yz426, but I've also heard that a newer carb is a hot ticket for these bikes. You can find them pretty cheap on eBay.

I don't remember which specific one, but seems like I've seen people say that the 2005 works great.

Just a thought, depending on how much it costs to fix the current one.

... I've also heard that a newer carb is a hot ticket for these bikes. ... seems like I've seen people say that the 2005 works great.

The '05 and up is a good choice because that was the year the leak jet was added, making them that much more sophisticated, but '03 and '04 are an improvement over stock.

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