02 YZ 426 starting issues

Ok, first off, YES I DO know how to start it using the manual decomp lever. It's usually on in the first or second kick. Today after starting it up and heading down the driveway I shut it off and when I tried to start it up again it wasn't having it. I tried the choke and nothing. I even tried the hot start. after letting it sit for about an hour I tried again. I started on the first kick but I had to keep my hand on the throttle. I adjusted the idle without luck and then it died. This would have been very frustrating on the trail. It's like it's flooded but I've ruled that out. Has this happened to anyone before? and suggestions?

Try changing the spark plug. Sometimes YZF's will gas foul a plug when they don't get completely warmed up before they get shut off.

I've had that happen to me before with the ol' 426.

I always just held the throttle,hot start and compression open (don't pump the throttle) and kicked it 20 times or so. That always worked for me except once and that was a spark plug issue.

Yea sounds like a spark plug problem.

You didnt mention it, but did you just clean and oil the air filter? Mine did this once when I got in a hurry and put the filter back in when it was still to wet, the solvents hadnt eveaporated out of the oil yet.

The filter oil clogs the air bleed orifices in the back of the carb, they are very small, I pulled the carb and sprayed out the bleeds whth brake cleaner and blew them dry, then it was good as new.

Now I keep a couple extra filters around so I dont have to wait for the oil to thicken up.


Yea I noticed that about the No Toil air filter, so I bought a second one. That definintely wasn't the problem. The day before this happened I did some riding and on the way home I washed it at the local car wash. Maybe that caused it?

I would change the spark plug before doing anything else. As 642MX said they will foul under the conditons that you state. Has happened to me a coulple of times.

I've had that happen to me before with the ol' 426.

I always just held the throttle,hot start and compression open (don't pump the throttle) and kicked it 20 times or so. That always worked for me except once and that was a spark plug issue.

This is the one that worked. I even counted the kicks and it started on number 21. Thanks

Ya i would say spark plug too,

i have a YZ400f, and ive fouled a couple plugs, by not starting the bike right (flooding it) and by shutting the bike off when its cold, and then trying to start it back up again.

Ok. So I'm feeling kinda stupid. After I got it started I let it warm up completely before touching the gas. As soon as I did, wouldn't-you-know it happened again. So I went straight for the spark plug. They're kind of a pain to get to, but once I did I found the shaft full of water. I blew it out with the air hose changed the plug and it runs like a champ. Thanks for tips and suggestions.

..once I did I found the shaft full of water.
Look for a 1/4" hole on the right side of the cylinder head. When you find it run a rod through it to clear it out, and/or blow air through it. That hole is the drain port for the spark plug well, and it should never have filled with water.

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