… and it was a handful when I first started out (just 3 months ago), but I’ve got a pretty good handle on it now. My worst transgressions now seem to be not rolling off the throttle enough when shifting, so the engine revs up a bit.
Anyway… KBB is a big help: http://www.kbb.com/kbb/Motorcycles/Default.aspx
My SV had 4100 miles on it when I bought it, and I got it at blue book. Aftermarket parts/mods really don’t mean much to the price of a used bike. Yeah, the seller usually wants to recoup the cost, but if they were smart, they’d hang on to the stock parts to put back on before selling, and then sell the aftermarket parts separately.
“Low” and “high” mileage are more relative to how the bike has been maintained than any absolute number. A meticulously maintained bike with 20K miles can be in much better shape than a bike with 3K that’s on it’s original oil. You are somwhat at the mercy of the seller’s say-so as to what’s been done to the bike and when (maintenance records can help).
Hope that helps.