Deciding Whether to Rebuild

[Raygun]

Hi all,

I've just bought 2x Honda CB550Fs with the idea of combining to make one.

The previous owner told me that one of the engines ran recently, but has sat for around a year. Similar for the other.

The carbs clearly need a rebuild and I am planning on doing so, but should I re-build the entire engine? I'm unsure of its past and shining a torch down the valves show it's pretty grubby in there.

If so, would just a top-end rebuild suffice to 'check, clean, reseal and reassemble' or should I do the bottom end too?

The engine turns over, and I'm told it has good compression. There is no obvious signs of corrosion and everything /seems/ in order.

My workshop facilities are not great, so I'm eager to minimise doing unnecessary work if I can.

Raygun

[Nurse Julie]

Welcome to the Forum Raygun. You really need the official Honda Crystal Ball to answer your questions 😁😁😁. Whipping the sump off and inspecting what bits of debris / metal glitter etc (if any) are present in there and on the oil pick up screen also tells you a lot.
Have you got all the manuals etc, if not, they are in Aladdins Cave for you to download.
Good luck with your project.
Edit... Which model 550's are they, F's or K's?

[Raygun]

Thanks Julie,

Cheers for the tip. I'll take a look underneath and at the oil screen. They're CB550 'F's.

My main concern is that they've sat with the carbs off and tappet covers off in a shed which could have caused dust/sawdust etc to be sitting arouns those open parts of the engine.

R

[Bryanj]

2 quick oil and filter changes and a couple of carb O ring kits from Julie will fix that

[Nurse Julie]

If they have been sitting without tappet covers on and the carbs on, you really need to strip down to inspect barrels / pistons as a minimum.