You should consider a little about the motoring situation now.
Currently, COEs are at it's lowest in months. That means, new bikes
becomes relatively cheaper (or at a glance seems cheaper). Economic
condition is Singapore now is pretty bad, many bike shops are stuck
with second bikes they can't sell.
My suggestion is, spend a little money to make-over your bike to
make like changing the lights, throttle, seat cover, etc. You'll be
surprised it make a difference in the resale price. You will notice
that owners will buy from you instead of the hard-bargaining shop
people. I know a place where you can do all these cheaply..if you
are interested.