1)check front fork seal see got oil leakage or not, if got
change need $$
2)high rev the engoine and see if got misfire or not
3)check all wear and tears and note them down if wana change hw
$$
4)dun be kan cheong, ask a frenz who rode bike for a time to go
with u, so u wun have the idea of, wa this bike is nice, i want it
now
5)check all motor tiams in singapore for the platre and price of
it
6)test riding, rev the engine hard in as many gears as you can,
then shut the throttle off, go down hard on the over-run, and whack
the throttle open again. If it's going to jump out of gear, this is
when it will do it.and also check from front to end while waiting
for ewngine to cool down , then start from cold and see if it is
able to start easily
Also, as you whack it open after going down on the over-run, look
behind you for smoke. This action forces oil into the bores. A
little puff of smoke is normal. A cloud isn't, and means the rings
and/or valve guide seals are worn.
See if it steers properly hands-off. Beware wobbles! If it shows a
reluctance to turn in one direction and a tendency to dive into
another, the frame is probably bent from an accident. (only to be
attempted by an experienced rider)
Try the brakes, hard, several times. Make sure you aren't being
tailgated when you do this....
When you get back, listen again to the engine. It should sound
quieter and sweeter than it did when it was started from
cold.
7)Chain & sprockets:
Look at the wear indicators (if fitted) and the chain adjuster
marks (if not). If the rear wheel is pulled far back on the
adjusters, the chain is worn out.
See if you can pull a link off the rear sprocket. if you can, it's
shot.
A dry slack rusty chain will also cast doubt over how the rest of
the bike has been looked after.
Look for wear and hooking on the sprocket teeth
check if disk is crooked, if crooked, got signs of
black marks on disk and when moving off will have rubbing
suound
9)Rear suspension:
Grab the rear tyre and try and move it from side to side. Play here
means wear in the rear suspension bearings. This can be easy or
difficult to fix, depending on how complex the rear end is and
whether the bearings will be all seized and rusted into place.
Assume the worst.
Bounce on the seat. A dry creaking noise from the suspension
indicates worn and seized linkages. This can cost up to S$150 to
fix. The rear end should also bounce once, returning to its former
position. If it boings up and down two or three times, or just
sags, the rear shock(s) is/are worn out. This will cost at least
S$250 and maybe as much as S$800 to replace with a decent
aftermarket unit on a big bike. Twin-shock bikes are cheaper, but
still allow S$150 - 200.
and lastly try both front and rear brake hard!
thats all 
