I bought my 06 S2R800 new, sold it last fall and only put 18K on it or so. Very bullet proof bike for the most part. I did experience the expanding tank problem though twice. The second time the dealer drug their feet on the repair then denied me due to law suit deadline. I was pretty upset, voiced my opinion but no one cared. That's fine they don't need my money anymore.
I broke the oil temp sensor once. My fault though I either kicked the wire or took off the clip wrong. Easy fix and only $60 or so.
My plastic crankcase breather developed a leak. Once it did I just bought an aluminum one and replaced it. I like the Nichols crankcase breather myself.
Other than that everything was upgrades, maintenance, and upgrades.
Manuals
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Workshop Manual S2R800Owner's Manual S2R800Spare Parts Catalog S2R800