CB500 Frame differences U.S. vs UK

[Scotty67]

Hi there. Apologies in advance if this question has been asked already, I did a search on 'frames' and a lot came back .

Anyone  know of any frame differences between a UK bike registered 01 Jun 1972 and U.S. frames 1971-176?
Thanks,
Scott

[Trigger]

The UK and USA  500 frames are the same and the 500 frame was also used on the USA 550K0, K1 and K2 as far as i am aware 

[Scotty67]

Fantastic, thank you!

[Scotty67]

PS. The 500 I bought came with a spare 550 engine. I assume that will bolt in OK? Cheers Scott

[Trigger]

It will fit but, the rear engine bracket is different on the 550 and don't expect anymore power as both engines are rated at 50 BHP 

[Sesman]

Does a 550 motor produce more torque? I seem to recall all the mags at the time lauding the 550 as a significant riding improvement over the 500 motor? Maybe just the usual journal hype. I’ve never ridden either, though hope to have mine on the road this year.

[Scotty67]

Thanks Trigger!

[Bryanj]

Gearbox, gearchange and clutch operation were biggest changesplus crabkcases casting had slight difference so primary chain does not hit oil gallery quite as much