Topic: CB550 build date question

[Scott S]

 I found a great deal on a CB550 head. However, the seller says the bike has a build date of 10/73 and was titled as a 1976. He has the bike in pieces and I wanted to make sure the head was, in fact, for a CB550.
 Did they start the '74 model year (which should be a 550) by 10/73?

 I asked for a bore measurment of the head. Will the combustion chamber measure be 58.5mm if it's a 550?

[dave500]

same heads,?the parts numbers are the same.

[Scott S]

 The combustion chamber is the same size? It didn't grow by 2.5mm when they went to 550?

[dave500]

apparentley not,same honda part numbers.

[SohRon]

'74 Cb550 production started 7/73, and the model year ran from July to July, so that's a '74 CB550 made October of 73; though that doesn't really say much about the engine. You'd have to get the numbers off the engine to get an idea of when it was made. They do get swapped, you know.

Some states (for some reason) title the bike with the year it was originally sold, rather than when it was manufactured (or by production year, that is). So this bike, although technically a '74 model, might have sat in the showroom for a year or so before it was sold in '76.

[Scott S]

 Well, if the 500 and 550 heads interchange, it doesn't matter.

 Before I was into motorcycles, I was into air cooled VW's. If you went with a different bore, the heads had to be bored to match. I guess that's why I was concerned. Either way, 10/73 is a 550, so I should be OK.