If your are building a replica bike the OEM shock is ok, but if you are planning to compete, the OEM shock is a bit archaic. Several aftermarket shocks are available that far outdistance themselves from the stock YZ monoshock. Of course you can expect to pay from around $600-$1200 for them. I don't think rebuilding the YZ shock is very complicated but I had Steve Sage (http://sagesuspension.com/
) rebuild mine for about $200. Why? Well I'm cheap (I had to pay taxes too!) and I wanted to see how the stocker technology felt before upgrading. Plus I've had yet to start my 465G model that I've been working on, as far as I know it may not start. I hope to find out soon as this time next week I'll be on my way to Diamond Don's Nationals (www.diamonddon.com
) for Beta testing. In fact I have to start putting together the bike today, right now the bike is totally stripped down.
One other thing: Yamaha really boned up the handle bar position and stock triple clamp. They have the bars sitting in your lap which I don't like, but that's 80's tech for you. When I can I'm going to do something about that but it will cost a few bucks. Moving the bars out and up will make this bike better handing and more comfortable as it helps keep rider weight forward over the front end which helps steering input and the front end down under power.