Please let your customers know that 70's model Honda CB550s Fours (and probably other Fours) are NOT compatible with O-ring chains! There is very little clearance on the original chains, and if an O-ring chain is used, it WILL wear a groove in the engine case and main shaft oil seal, causing massive oil leaks!

Older Triumph motorcycles have the same issue

From the UK:
I wanted to remove an engine from a motorbike, the drive chain did not have a connecting link and a friend who said he had been through the process told me the best way to get the engine out was to remove the rear wheel chain guard and swing arm, when done the chain run still went through the frame, I called my friend told him my plight and he said he had the same problem, so he bought a chain breaker and would I like to borrow it. I had mixed feelings anger 'why the f**k did you tell me you had a breaker, you %$^^^^^&)(*%$£"~@{?>< monkey to submission, Yes mate I would like to borrow the tool thank you, he did lend it to me!

About 3 weeks later, after I done all the work on the bike installed the engine, swing arm, chain and chain guard, I was telling the story and after he stopped laughing he said as I wasn't replacing the chain all I had to do was remove the driver sprocket cover and lift the chain off the driver sprocket and leave the chain in situ. - Who's the monkey now