Need some advice on two stroke bikes
I have three sons. They are 17, 14 and 10. The 14 and 10 year old have decided they want to race motocross. The 14 year old wants to make it a career. The 10 year old is in it for the fun.
Here's the deal... we currently own four stroke Honda CRF's. We had three and are down to two... an 80 and a 100. We are selling to buy two stroke bikes. Looks like we are looking for a Kawi KX 65 and either a Yamaha YZ 85 or Honda CR 85.
I know nothing about two stroke bikes. I am an engineer and do most all of the current maintenance on our bikes, which isn't much. They just don't need it. I see adds for the two strokes with rebuilt engines...pistons, rods, etc... and then with just new reed valves.
Are they difficult to work on? Do they need constant adjustment/work or whatever? How long do reed valves last? Easy to replace? At this point I'm not even sure what to ask... I don't know what I don't know.
Any ideas what I should look for when I go look at these bikes? Any problem areas that I can focus on?
Any and all advice is appreciated.