Any tips when buying a used bike? What do I need to look out for?
From what I can remember(in no particular order):
1. check the bike for any leaks, around the front forks, under the frame, brake fluids and so forth. There may be oil leaks around the brake calipers
2. check tyres to make sure there is enough thread on them
3. check the chain condition, and tension. You should have about 25mm free play in the chain. if the chain is rusting in places, will need replacing soon. If very oily, sign of over lubrication, might say something about the owners maintenance of the bike
4. ask the owner not to start the bike before you get there. Then start the bike from cold, listen for any funny sounds or knocking. This could mean engine problems.
5. if you can, check engine oil level(sight glass on right side engine cover). There must of course be oil in the bike.
6. check body work for scratches or dents. Also check mirror ends, handlebar ends, front forks, mud guard on front, foot pegs and so forth. Any scratches could mean the bike had fallen, or brushed against something.
7. check license disk is valid, and license number matches chassis/engine number. If the bike comes with a road worthy certificate(it should, negotiate this if it doesn't), then these checks already done for you.
8. Also speak to the owner, check out why he is selling. Maybe upgrade, no time for riding anymore, financial reason, whichever. From this chat, you can find out what type of person he is, as this will give you an indication of what type of ride he is/was(just his behavior and how he answers should give you a good indication).
9. check if bike has service history(service book or log). If not, find out when last was the bike serviced, and what all was done. Ask what mileage he has on the chain and sprockets, brakes, tyres, etc.
10. check for loose panels on the bike.
11. get on and sit, check brake pressure on both front and back. check clutch lever pressure. See if you can select first gear, and back to neutral. This action should be smooth, and you should get a good clicking sound when doing this.
That's what I can think of on the top of my head. This all while standing by the bike. The road test, if possible is a different story. Generally, when you hear the bike running, sit on it, and give it a once over, and the owner is of the respectable kind, you can almost be sure the bike is in great condition. I bought mine without test driving(I didn't have my kit when I went to view the bike), and the owner was a great guy, bike was in great shape, and it's still in great shape after me putting 2000km on it already.
Just remember, it's a risk you take buying a used bike. Take someone with you that has some bike knowledge. They might see things you can't. They might ask the questions you forgot to because you're too excited for the bike. And take pictures, study them when you get home. Sometimes you may see something in the picture that you didn't see when you were there(scratches, marks, bent leavers, etc).
Oh, and make sure the bike is clean when you get there. If bike is dirty, and out of shape, walk away as that is a sign the owner never really looked after the bike.
Hope this helps