Today i removed the rod mains and inspected them, they all looked mint apart from one which had minimal wear.
I replaced the one which had minimal wear torqued everything up and put it all back together.
When i started it, the same knocking noise was there straight away.......
Im starting to think its the crank mains now, do i have to remove the engine to replace them, and do i have to remove the crank? can i not just drop each side of the crank to replace them?