The Best of - Buying a 150 Bike advice

I’ve trawled through a number of posts in this forum but have only found one or two tips pertaining to the following points:

  1. Where are the best locales in Taipei to visit reputable bike shops (for motorbikes, not scooters)?

  2. What are the most important things to look for when I test drive a 2nd hand bike?

  3. What kind of warranty should I seek from the shop?

  4. How much negotiation typically occurs on prices here?

Can you more experienced folk out there run me through the BikeBuying.101?

I am looking at buying a used Sym Legend 150 or a Hartford 150 with a budget around $25k. I was put off the KTR150 because it looks like it rides a little high and could be uncomfortable/unstable for someone over 6ft.

Any help is much appreciated.

I suggest reading this thread thoroughly. It contains answers to most of your questions.