Hi guys ! Thanks so much for the replies, I really appreciate it!

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I don`t think it has anything to do with the downshifting.
Last winter when I crossed a lake (it was snowing, at night, with only 4-5 meter visibility, and there was about 40-50cm with powder on the lake, I was riding slow, 20km/h maybe, suddenly the sled wouldnt move forward, the engine was bogging so much that it simply wouldn`t move.
So, it can`t related to variator problems?.
However, I did noticed the snow had built up in the air vents, but a few months later I taped off all of the air vents and the sled still ran great, however the snow was packed when I did it (I thought there were powder up in the mountains) so I don`t know if it would have ran OK in powder.
I have a hard time believing that a huge exhaust deflector will make it healty, when I look at my friends with V-Max 600`s plowing through the powder with no bogging problems what so ever, can`t see why they shouldn`t have the same problems.. .
I cleaned the powervalves at the end of last season, they were all sliding nicely, however one of them was out of adjustment, so I adjusted them. (removed the piped and felt that they all were flush with my hand).
Gees it`s so frustrating, I`m a Yamaha guru, I love the sled, handles so nice, but all the bogging makes me check out more and more 4 stroke adds.. I had an RX-1 one year ago.. instant throttle control, no hesitation, low fuel consumption.. but it doesn`t scream as nice as a three cylinder two stroke

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Well, soon I will trailer my sled up to my shop and start looking at it.
Could moisture combined with bad wire harness be causing it?.
Should I remove the engine to check the wires or?.