I hate to say this John, but even if you end up buying a dirt squirter for that price you will ultimately end up spending more money on making the bike reliable and the enjoyment you would like to spend goes down the chute along with your desire to ride bikes!
I don't know what your budget is but, surely you could get a small loan for $3500 to get yourself a semi decent bike!
The biggest problem with such a cheap buy is the reliability and the fact that the bike would have really tired suspension and probably worn tyres that make the whole riding experience a bit poor!
Do you see where I'm coming from? I did this and yes I thought it was a good idea. The bike I bought was really cheap but the tyres were flat it had no power and it was really old. The suspension was from the model T Ford era!
Anyway, even if you could buy a slightly pricier machine, invest in some off-road safety gear. I know this sounds a little bit soft to a few people, but I've had that many stacks on my KLX-450 and walked away from them all. The bike is an 08 model and I've put just under 1000kms and it looks like its three year old. I love it though. I ride the damn thing hard and love every minute, more so than riding my 10R!
Hope this helps mate,
Troy
