son wants to start on kx 80

my son 10 yrs old wants to begin on a kx 80 i was thinking klx 110 he love the beef and wants a clutch even though he never used a clutch before. He only rides a 50. he is 4.6 a tall well proportioned and weighs 70 lbs ya i know, he is a determined boy who is very physical in all sports and top of his league in every one he is very competitive. he will ride in open field and yard this season next year when i get my bike well then we can go to the trails and take it from there, as i said in the my son has only road a 50 for a while no clutch, handles it well he looks ridiculous but he loves the feeling. as for as racing i can't afford that sport he has already asked "mom if i get good enough would you put me on a racing team?" i personally have never worked on a dirt bike but i am mechanically inclined more than the average person so if its routine or possible we will together learn to maintain our bikes, my son has what seems to be a preference toward kawasaki don't know why and as for as motor choice I'm a green horn that's why we are here, there are a few used dealers around that we have been watching my son has been saving we have to catch a deal no more than 800. all input welcome. please help us decide which bikes are worth his savings and appropriate thanks

thank you

son is 10 yes we are definitely looking for mechanically sound bike and the only real preference to brand i see that he should not buy is one of the Internet specials i say that with no experience just don't wan't to see him get burned if i'm wrong than we may have passed up some great bikes cheap.

thank you

i don't want to hold him back i't just been a long time since I've been around bikes and i don't want to wast everyone's time going to look at bikes that are to big. just want to look for something that he going to ba able to get on and will last a while. yes protection a must thanks again

need advice

2000 Yamaha rt100 dirt bike for sale guy wants 550 obo called him asked about the bike he told me the muffler needs to be welded on and the forks are slightly bent but ride able sent me pics do you think we should even think about this or is this already to much of a headache , my oldest son is graduating from a trade school welding is is trade and he is real good. thanks for your help.

thanks

ya been doing my home work ome parts 250. ant cant locate them else ware still checking the bone yard (cycle pro)just for the heck of it wonder if its something me and my son can do?