Sooty spark plug

Maybe someone can give me advice about my 2001 YZ426. I had it start missing and popping this summer after riding it for four months. It always starts and idles fine and will run fine for a couple of weeks before the plug goes bad and needs to be changed. It doesn't seam to be a jetting problem because it runs to well, and I follow the YZF rules of not turning the throttle when starting and letting the air filter sit for a couple of days after oiling before riding. I went to a CR7E and this helped but it still doesn't last long enough. I sometime take off to quick after starting and I think this is part of my problem maybe the bike is to cold to burn off excessive fuel.

Different bikes seem to have different solutions when it comes to fouled spark plugs, but for me and my '01 the answer was changing brands of gas. I was fouling one almost every time I started it while it was cold (first start of the day). I changed brands of gas and with no other changes at all I have not fouled a single plug since.

On my 01, the best thing I did was to start running a 50-50 mix of VP 108 octane and 92 octane pump gas and did the BK mod. Starts first kick EVERY TIME and have been on the same plug for 3 months now!

These guys are right, the gas can cause this problem. The ethanol in the gas (madated near Denver in the winter) will foul my bike right away with a CR8E plug. A CR7E plug won't foul right away, but it sputters and runs poorly. Do not use gas with ethanol in it!

Same story, different verse. A buddy of mine was having troubles with his '01 after the weather has turned chilly. Couple of weekends ago he decided to try 112 race gas and a 1 step leaner main jet. He reported a nice tan plug at the end of the day.

(Mike O, I tried to email you this but you might never have gotten it)


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