This is a good drift for helping remove a big end . I made it from a piece of old steel scaffolding tube off-cut which happened to be on the edge of a pavement I was walking along near abuilding site ! 

 

Inevitably a new big end is expensive as it is made of very high quality steel and rollers. This one cost me £130; but for single cylinder Norton's I have seen the same bearing priced at £200 and I don't mean for a Manx model which is very different type of big end bearing.