White powder inside #2 header

Hi all,
I took off my 4in1 Vance & Hines exhaust this weekend to take it to a muffler shop for some reshaping (previous owner had flattened it a bit on the underside) and noticed that one of my pipes at the #2 header was white. The other 3 were your standard black.
What does this mean?

Pull the #2 plug. Chances are it's white as well - that cylinder is running way lean. Carb problem.

by chance did this bike come from colombia?

columbia is a possibility..lol:P running lean on that cylinder..definitely pull the plug..if kept at that it will cause you problems...like a hole in the piston..:pinch:

I recently changed the plugs about 2 weeks ago, but #2 already shows a white deposit.
What's next? Carb adjustment of some kind or carb rebuild?
After phrasing this post, I got the feeling I'd get the coke jokes:lol:

Also, in response to Brian's comments "if kept at that it will cause you problems", how long (days, weeks)?
It's a daily rider for me with a 10 minute commute each way. Besides that I haven't riden that far since getting it running 3 weeks ago. I won't be able to get to it this weekend, so the soonest I could do some work on it(short of a simple adjustment) would be next weekend. Is that risking a hole in the piston?

Do a compression check, chances are pretty good that the white powder is alum. if comp. is good than you can check elswhere

I will do a compression check. I just read a thread on that here and have the clymer. Probably can't hurt to get that readings regardless.
I don't have much history on this bike. I picked it up about a month ago. Had to install new Dyna-S (as it had been laid down and torn off by previous owner), changed oil, oil filter, spark plugs and cleaned K&N air filters. That's the engine maintenance so far.
One thing that may or may not help, is that the oil that came out of it seemed a bit milky. I expected more of a dark brown/black color, but this was light drab milky brown. No metal shavings to speak of in/around the oil filter or plate.
If compression readings come out satisfactory, what are the options on the carb(s)?

Milky is pretty weird for a motor that is air cooled. Milky is usually found on water cooled motors with bad head gaskets letting coolant into the oil. That only leaves 2 options, gas or water. If it was stored outside I guess it's possible for water to get in there. Or condensation over a period of time maybe. Either way with your possible lean condition on one cylinder its probably time to take those carbs apart and give them a thorough cleaning if nothing else. There is no real time table for burning a piston. You may just hit the throttle one time and that will be that. If it were me I wouldnt risk the motor until you know what's going on with it.

Ron

Ok, I get to finally contribute! Thanks all for your answers. I did a lot of research in these forums and wiredgeorge's website (pics of carbs) today and took a close look at my carbs. Specifically all those vents that seem to want to be connected to something. All of the ones under the bowls have tubes connected to them, but there were a couple on the top/back side that come out at an angle that weren't connected to anything. Learned that those were vents that have to be open (I guess it's recommended that they also have tubes on them to prevent crud from going into them, but they shouldn't be sealed up)
Then, I took a look on the under side of the carb holders (black plactic/rubber rings between the carbs and where they connect to the engine) and spotted that one of the vacuum plugs didn't look like the others. Where was it? #2!:blink:
Some idiot had replaced the black rubber nipple vacuum cap with a black rubber hose, basically allowing air to flow freely into #2.
Plugged the hose temporarily with a screw and headed off to the auto parts store. Bam, problem solved. No more backfiring, slight hesitations or occasional strange psssshhh sounds. Took the opportunity to replace all four of them for $1.50 (3/16" or 4.76mm rubber vacuum caps)
I'll monitor that plug just in case and will update if needed.
Thanks for the suggestions on the carb cleaning and compression test. I will do that soon enough anyway, but for now I think the problem is solved.