Hi again, posted about my TRX 300 noisy engine in the newbie section. The story continues. I spent an evening listening to top and lower parts of the engine with a bar to my ear. Still sounded top end to me, but i was truly not sure, Had one of those begger it!! Moments, And decided to take the engine out the bike and get it back on the bench where i feel happiest. Long story short, thats where it is now. Head and barrel off, i proceeded to check out the rod bearing (as you call it) I was surprised and delighted to find it was really good!! no noticeable movement at all. Better than i could hope for. I pushed out the wrist pin and tested this as it says in the haynes manual, by pushing it in to the small end bearing and giving it a waggle. In the picture in the book, it shows the pin just in the small end of the rod. This is how i tested it last time i had the engine out. At this point the pin looks as though it is reasonably in limits. As i was doing it i could see the centre section was marked and warn! Obviously.... Well it is now, thats where it should be tested! not on the ends that sit in the piston and dont move!! eureka. I pushed the pin to the middle and rocked it there, and it is as slack as a slack thing. I am now hoping this will be the problem and the cause of the noise? My question is. I have the chance of a used piston and pin for what would be about 30 of your dollars. I am not too sure as yet what a new pin would cost. But would it be best to get the new pin in the hope it will take up more of the slack, if any that is in the small end of the rod? Thanks....Pete.