Kid Rocker just saved my a** yesterday with a similar item. (check out "am I paranoid" posting) Sounds like you may have a lean condition as well. You are either suffering from limited fuel or an air leak. That's my best guess. I'd start with the carbs as well. Did you happen to pull the plugs? If so, what appearance on which plug?
MXZ--700, My 2000 does the same thing, when I come to a stop sign or set and idle for a little while, it goes up to about 2600 rpm's, I just hit my choke and it settles back down. I have talked to my dealer and a lot of other people about this and everyone tells me it is a normal thing. I have over 2500 miles on mine with it acting like this. If you are unsure, it wouldn't hurt to take it to the dealer. I would clean the carbs, and sync them also. However, if it ran good before, and has done this from the start, it should be ok. In fact I was riding with Idooski last week and his new 800X with dpm does the same thing, in fact both of our sleds reached the same rpm's before hitting the choke cable to bring it back down.
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