Topic: Looking at a '77 CB550F, rattling and stuck cam adjustment nut.

[VGplay]

Hi everyone. I'm in the market for a CB and this site and r/HondaCB have been awesome resources to read and educate myself. This would be my first motorcycle, I have decided that I like the classic Hondas enough that it is either one of these or none at all. That said I am decently mechanical, though with modern cars more than anything. I'd be confident and willing to sit down with a service manual and learn along the way. I have looked at this 1977 CB550F that is in fairly nice physical shape:

https://i.imgur.com/fY4B1iV.jpg

The bike has 23k miles. It starts easily and continues to idle. Carbs need cleaned and likely synced. It will need new tires. The only thing as far as I can tell that is out of the ordinary beyond usual maintenance is some rattling (the seller says) from the cam chain. Which is then compounded by the adjuster nut being stuck.

The seller posted this video of the rattle:

What could I be in for with the nut and rattle? Ideally it can be broken free and the adjustment mechanism does the job to remove the rattle. But I know enough that ideally isn't likely. I made a thread in r/HondaCB and the replies there didn't like the sound of it and recommended posting here.

I appreciate any help! Thank you!

[TwoTired]

Looks familiar...

Got a manual?

Cam chain adjustment is to position the crank so the cam chain slack is on the adjuster shoe side, Loosen the nut, maybe wiggle the nut stud and then tighten the nut.  As loose cam chain is more of a hiss or tick, than rattle.

After that, rattles are usually the trans gear clack for improperly synced/balanced carbs.  Does the rattle change pitch when the clutch is pulled in?  If so, not cam chain.

Looks like a good bike to keep stock, rather than chop up for a custom abomination.

Cheers,

[BRG-BIRD]

That’s a pretty clean CB550F, good luck with what you decide to do.

[bryanj]

If the adjuster nut has been forced it can damage the rack teeth in the tensioner which means a top end off(can be done in frame) and replacement tensioner mechanism. DO NOT under any circumstances put a screwdriver in the slot with the intention of making the cam chain quieter----this is what wrecks the mechanism!!