1959 Triumph Bonneville Pre Unit T120 Engine Disasembly Pt 2

Please note this is not an instructional video. I am an amateur enthusiast making a record for my own pleasure and adding to the bikes history and sharing it with you. It’s for entertainment.

The reason for this engine overhaul is my oil tank was virtually emptying itself out the engine breather onto the floor with very little being returned to the tank. Having fitted a new quality oil pump, ensured all oil ways that I could get to were not blocked and the oil pick up was still secure all my initial efforts failed. So it was time to dig deep with a rebuild. Not knowing the history of the bottom end I am taking advantage of this opportunity to have new con-rods with modern big end bearing shells, main bearings, new pistons, and possibly new cam bushes after inspection. All this work is being carried out by a professional company who are also going to dynamically balance the crank and clean the sludge trap out. I am hoping the reason for the initial oil problem will show its self during the engine dismantle.