I've been glued to this blokes channel because he's been uploading daily takes on the rebuilding of a one of kind Norton 650 prototypes. Most of them are short takes concentrating on each specific fix.

The bike's making some nasty sounds on the over run which I'm sure are drive chain related. So in the comments myself and other interested chaps are offering our suggestions as to the probable cause and Paul's thanked me more than once for my suggestions.

I had a Norton 750 Atlas so I know all about their propensity for destructive vibrations which are a constant source of bizarre damage from both high and low frequency vibes affecting the tinware as well as ancillary parts, its a never ending problem almost forgiveable for the wonderful roar and gottdammerung sound of thunder.

Most of the 60's British big twins had similar shortcomings caused by poor design and slapdash assembly but the conscientious rider/mechanic could eventually eliminate all but the primary source caused by the rocking couple of a twin cylinder long stroke engine and the lack of rubber mounting which is how the Japanese, particularly the Suzuki two strokes, got such ferocious yet reliable performance from their twins.

Even the exhausts were rubber mounted along with the engine, handlebars and almost everything else in the drive train! Had I the money and facilities I would have tried different firing sequences such as 180 degree cranks and even parallel pistons.

However here's the link to Pauls channel, check it out if methodical mechanical rebuilds interest anyone.

https://www.youtube.com/@paulhenshaw4514