Man, it seems on the REX it has a serious tight chain compared with other bikes. Several years ago I was at a bike dealership, and the Head wrench said my chain was WAAAAAY too tight. So, he adjusted it the way the Suzuki's were setup. When I got home and looked up the adjustments on the ZRX Manual it stated that the total slack was to be 3/4 inch total up & down movement. I just checked my chain today and readjusted it...but is this normal for most bikes, or is it just the REX with a "Tight Chain"? BTW I'm still running the stock chain, and it has 23,000+ miles and still going strong.