Popping Backfiring Dead?

My '98 YZF Has been acting up and I dont know what to do. It pops and backfires and then dies. Then if I change the plug which is carboned up it will usually fire. But the last couple of days it keeps popping and stalling until up to full operating temp. (hot) then it stops. Then I left it sit for a while and rode again and it didnt pop but it suddenly stalled and wouldnt fire again (probably would have with a new plug) HELP!!! I love the bike but this is such a pain!!!. Incidently it usually doesnt do it in warmer weather. :)

Could I have gotten water in the fuel system? How does it act under those conditions?

What altitude are you riding at?

Do you have the stock jetting?

It sounds to me like your fouling a plug which could be caused by many things. When I fire my WR up, I try and minimize the time I spend with the choke on. If you leave the choke on too long, it can lead to a fouled plug. I only choke it for less than 30 seconds and I use the throttle to keep the rpm's up so it won't die after I put the choke off.

Also your jetting is suspect if your fouling a plug this easily. That's why I ask what altitude you are running at and what setup you currently have. If you are running at sea level, this probably isn't your problem though.

The other day I was riding at about 8500 to 9000 feet here in Colorado. I knew I had good jetting for this altitude since I've ridden my setup before. It was a cold day (mid 40's) and I started the bike with the choke on. When I put the choke off, the bike started loading up like it was about to foul a plug. I cracked open my hot start button to lean out the fuel mixture just until the engine stopped loading up. Once I had it back, the bike ran fine the rest of the day.


I am in Michigan, and the jetting is stock

I'm just southwest of you in the Chicago area, and fouled my first plug this weekend. I was warming the bike up for a few minutes to check the oil level and got side tracked getting my equipment ready to ride. Well, I left the choke on. It was really tough to start all day, and usually it's a 1-3 kicker even hot! It also Backfired a couple of times trying to start it.

I just got back from the garage and swapped in a new plug.(Is there an easy way to get a new plug in?) The old one was black and sooty. With the new plug it started right up with 2 kicks. Good Luck !

Spark Plug removal design.. not well thought out. Pull the seat, tank, and use there plug wrench.

Anything easier, I'd love to hear it.

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