I have a 8year old cousin who desperately wants to ride a bike and I have no idea what to get him.
1) your physical size (both height and weight are important)just under 4' and about 65lbs
2) How physical / aggressive are you ?not very
3) what do you plan to ride- MX/SX tracks, woods, fields with friends or ?????he wants to ride with a youth club on an enclosed dirt track
4) Do you have any riding experience?none
5) Do you think you will race ?eventually
6) Are you mechanically inclined and will you be doing your own bike work?no and no too young but will have some help from uncle
7) Do YOU have a preference to a brand/ motor choice (2 or 4 stroke)?the safest is what we would want for him as it will be his first bike and he is very young
8) Do you have a dealer close by your home that you might use and what brand(s) does he carry?no
9) How much do you plan to spend on a bike?under 1000
10) Do you live in California?no
11) anything else that you think would help form an opinion not really
I just bought my 9-yr-old-son his first dirt bike. He is almost the exactly the same size ... a little taller 4'3" and 60 lbs. We bought him a Kawasaki KLX110. The others we considered were Honda CRF70F and Yamaha TTR-90. There are two important factors for kids this size and age: a) how well they can touch the ground and b) starting the bike.
The Honda has the tallest seat @ 26.1", the Kawasaki is next at 25.6" and the Yamaha is the shortest @ 24.5". At 4'3" my son is on tippy toes to touch with the Kawasaki. We bought it hoping the extra power of the 110 CC engine would keep him happier a little longer than the 70 or 90 cc engine.
Of the 3 bikes I've suggested, the only one with electric start is the Yamaha. This is important too, because most kids this size/age can not do the kick start, so some adult will have to start the bike for them.
Really the Yamaha TTR-90 might be perfect for your cousin.
the TTR90 is more popular( meaning its easier to find a used one), but a PW80 might be a bit cheaper. the TTR might be the better choice if you want a bike that is more similar to the bigger bikes, unlike the PW.
I would suggest a four-stroke trail bike. A XR/CRF, TTR, KLX, DRZ. Take him to the dealer and see what he fits on. I started my son on a 96XR100 at 8 years old. I wanted to start him on a clutch, at 8 they can understand the concept.