Help choosing between TTR-90 & CRF70

How tall is your son? Have you considered going for a slightly larger bike w/clutch? I say this because both of those bikes, while great starter bikes, are usually outgrown VERY quickly. Something like a CRF 80 may suit your son better(possibly even a 100), as it will teach him the basics of a real transmission and give him something to grow into, rather than out of. All the smaller CRFs (70, 80, 100, etc) have very tame engines that wont overpower your son and are very easy to manage, even for a newbie.

Ive ridden a CRF 100 which is slightly taller than the 80, and id say that anyone on the upper end of the 4-foot range should have no trouble riding these bikes.

At his age, you might consider the KLX110 as well. Thought you didn't tell us his size. Given the options, I would go with the TTR, the bigger motor probably produces better power for a growing youngster. As far as the plastic fading when it gets bent, they all discolor if creased, it is a property of plastic, it is just more noticable on the dark blue. There are many Honda loyalists out there that will claim that nobody else can compete in build quality, but all four Japanese manufacturers have a lot of experience, and each have had bad ideas. With any off road vehicle, bolts can come loose due to vibration, and metal can bend if it hits something hard enough. Personally, I think a dirt bike needs a kick starter, even if it has a magic button. Batteries die, and charging systems and starters fail. The absence of the kick lever is my best argument against the TTR.

My boy is 9 and i've had him on a crf80 for a year now,we have made several upgrades(hot cam, airbox modify,jets) It's a very good bike and has good usable power for it's size!! My vote goes for Honda crf 80 :nod: