Engine numbers

[yozzer74]

Does anyone no what model engine this is by engine numbers [ Guests cannot view attachments ]

[csd4t]

I would say tis a K6

[Trigger]

+1 with a CB750K6

[Bryanj]

Could be an F1, The us ID books sez they start CB750FE-25****** but I never seen one with an F in the engine number

[yozzer74]

Cheers it's my dad's engine he got it years ago when he was dispatching on it .is bike is an f2 is chain went through crank case.so he got this from a breakers some were can't remember were .but he did put is f2 head back on it .but I noticed today it had different pistons to mine .which is also a f2 I didn't think it would have run with those pistons in with f2 head and barrels on ??

[bytio]

 The F is an E I think when you zoom in

[Trigger]

Engine numbers can be a little confusing. I have in stock a K6, date of registration 07/10/76 with engine number CB750E-24681**. Another with date of registration 11/03/77 with engine number CB750E-24685** A little confusing, as they are both UK units but, have a CB750F1 with number CB750E-25501** which has the dome type pistons.

[Bryanj]

The US ID book sez K6 starts 24 and F1 25 so those numbers tie up, I always wondered if Honda sent engines back for rework and so numbers were not necessarily in order

[Trigger]

Honda would pull a engine every now and again for testing and throw it back into the line. I did have a K6 last year that was a late registration of 03/04/78 with engine number CB750E-25716** and it did look that it had never had a engine change.

[Bryanj]

I was told years back that the frames were numbered at the end of the line consecutively and the engines as built but if they didn't pass test they were pulled hence the engine numbers being higher than frame and diverging slowly