Hello. I have an 04 Trail Boss I purchased used, great condition, but had sat for a while with old gas. Prior to using, I drained old gas, disassembled/cleaned carb, new plug, new fuel filter, changed oil(M-1 0W40) and filter(Pure-One). The machine runs great. A bit cold-natured, takes a few to warm up, but runs great through the whole throttle range.
I checked the plug just to see how it looked and found it to be like new/white- No blistering or deposit like looking material, just pure clean and white. My first thought was Too Lean!!. Things I've done to correct to no avail: Recleaned carb-several times, adjusted float-several times,lowered needle clip(raising needle) to various positions, changed main jet from stock 122.5 to a 130 (to be extreme increase), played with idle screw adjustments, checked carb boot and filter/filter box. The plug stays white, no matter what I do. The plug looks black and sooty when just sitting at idle, but when operated through a range of speeds for 10-15 mins, plug check shows clean/white new appearance.
I did tape over airbox intake, which bogged it out from lack of air, also leans it out when lid removed completely. Then, I progressively removed layers until it ran good. This would darken the plug-not tan but lightly sooted look.
I got sick of working on it so I took it to a dealer for evaluation and explained all the above. They kept it for 1 week, charged 1/2 hr labor and said it was running fine, just a clean running engine, but keep an eye on it.(sighh) This all occurred last fall. I parked it for winter but it still bugs me, and spring is approaching.....Any thoughts on the matter would be greatly appreciated. Would really like to see the tan-ish color I think it should be, so I do not ruin the engine.
Sorry so long winded.

 

Granted 325 and 330 engines are cold natured because of lean pilot jet and just the nature of air cooled 4-strokes,but plug should not be white if that is what your describing,should be a medium tan. Are you running BKR7ES? If running a 5 or 6 might drop down one heat range. Haven't had any burnt up ones yet because of jetting, only one real problem child,that I had to drill out fuel air screw plug and found screw was turned out 1/2 turn from factory! Turned out two turns and eased problem. One note also in winter will run leaner than summer. Dont know if this helps. opt

 

Thanks for the response OPT.
I believe the 7ES is the stock plug, which I am using, and did switch to an 8, which I believe is a colder plug for a BK plug. It did not have a better appearance, so I kept it stock.
The machine has great power, does not backfire, and accelerates nice smooth and crisp (at least as much can be for CV carb). I'm stumped and frustrated.

 

Leave it alone or rejet the pilot jet, Have you done the proper spark plug reading Test ?

 

Do you mean a "plug chop"? I have not done that. I thought that was done just to tweak a particular throttle range jetting/needle position. After increasing main jet size and raising needle, without any effect, I didnt, thinking it must be something else, not related to the carb jetting. I just drove it through a series of different speeds and terrain, to get an overall idea of how it was running before checking the plug each time.