sarah, class 2 bike cannot test? from motortiam is it? quite
weird... =/ can at least start engine right? if new bike then
nothing to worry mar... 
anyway from front to back...
do a general check, see if the bike has stock parts (note anything
weird... like nisin calipers on a R1 
)
preferably you have a jack when you do this...
check steering cone, bearings
wheel bearings
brake pads, brake discs warped or not
forks (are they pitted, scratched etc)
fork seals, leaking or not (pump the bike up and down with front
brakes on to test this)
are the forks straight? sight down the triple clamps, or use a good
metal rule
check the tires for wear, treads (for wheels to avoid, look at
henry's... )
instrumentation working? test all of them.. high beam, signals etc
etc... test all the lights also...
bar ends scratched? lever ends scratched? (can be cheaply replaced,
but scratched is bad for sure)
turn the bars from left to right fully, check that the stop lugs
are intact.. if the bars hit the tank, check the lugs for damage,
most likely they are.. (damaged stop lugs show a high possibility
of a previous crash)
check the rear sets, are they original, or badly scratched...
again.. those to avoid are like henry's kekeke... no lar.. it means the previous owner is a
chao racer.. every other day bua ka tar... not very good for the
buyer if the previous owner didn't take care of the bike...
check the rear shock, pump it up and down, a "working" one should
have at some damping and not bounce up and down
while you do that, note any creaking or squeaking (one that's like
that has dried or seized bearings, can be expensive to change)
monoshocks cost from $500 onwards...
check the rear brake pads/calipers/disc like the front
check rear wheel bearings..
take a look at the chain and sprockets... branded? badly worn?
someone who doesn't take care of his chain and sprockets normally
don't take of the rest either... badly worn ones need to be replaced, doesn't matter
if they're LAB or afam ones... but the condition is a good
guage...
take a good look at the bike, it should have generally good
symmetry, meaning the left and right sides should look straight and
balanced.
check for stuff that comes with the bike, like tools, manuals
etc..
is the documentation intact? log card? also check that the chassis
numbers match the log card's.
eh.. this is all i can think of lar... notice i left out engine and
transmission testing.. let the rest fill this in lar.. cos i suck
at 4 stroke engines...
