Everyone reading this message do yourself a favour. Shut your computer down and go and strip your rear suspension . My YZ426 is only 1 month old (max 300miles riden) however I decided to remove the engine in order to do a gear ratio change (1st, 2nd and 5th).While the engine was out I stripped the rear suspension linkages just to check them out. All I can conclude is that the Yamaha factory had obviously run out of assembly grease when my bike was put together. The bearings condition were border line. Another month of riding and I would have been forced to replace most of them. Water had already entered the bearings and was mixing with the little grease that was still present. I count myself lucky, having just rectified the situation in time. This is one maintenance activity you have to do asap !!! Next stop steering head bearings.