IN-S40 wrote on 04/15/11 at 10:25:57:White spacer has been reduced by about 1/3. Seems to surge a little if the engine is running slower like 3rd gear doing 30mph but its is a very slight surge. Otherwise she runs fine mid and top end. I may be over reacting a bit? I just remember from my snowmobile days you wanted a nice dull brown. Not a grey or white but thats a 2-stroke, replaced a few pistons because of that.. I was thinking about pulling the carb and cleaning it in my ultrasonic cleaner but not looking forward to pulling it...
A tan color plug is the right color, that leaves a margin for a WOT run on a hot day. Mine looked more like yours, and that was 4,000 mi ago.
But I seldom do WOT more than 10 seconds at a time, and I don't ride on hot days, so I don't need a margin. If you are going to do 80+ for an hr on a hot day, you mite better give it a little more fuel.