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Decoding VINs to find out what my engine is... ?

mttprk

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Bought a 1977 CB750F Super Sport and I think it had a motor swap, need help identifying my motor to apply the proper fixes to have it road ready.

CB750F-21XXXXX on frame
CB750E-26XXXXX on engine block

Found these VINs for the K series engine blocks...

1976 K series engine CB750E-2428762
..............my engine CB750E-26XXXXX <<< my number falls between '76 and '77
1977 K series engine CB750E-2700001

So am I right to think my engine is from the end of the 1976 K series production year since my number is just before the 1977?
 
could be a k motor but the f2 had the same cb750E starting at 2600014. I have some conflicting info on the K and F number crossovers. Look on the cylinder head top fin on the cab side between cylinder 2 and 3....see if there is a 410 casting number. I think you have a f motor but need to look for a couple of things. Full engine number would help, these numbers are not secret and no one can do anything with the number so its ok to post it.
 
I have a cb750e- 253
Does anyone have something to help in finding any info. This number is off the block. But when I researched the carbs( style 4 inline. It states those carbs are off early style cb750 sohc. Help please?!
 
I have a cb750e- 253
Does anyone have something to help in finding any info. This number is off the block. But when I researched the carbs( style 4 inline. It states those carbs are off early style cb750 sohc. Help please?!
You've given too little information to get a good answer. What exactly are you looking for and to do???
Do you have the frame numbers and model of your bike too?

The engine numbers you posted show it is a 1976 engine case number.
The 1972-1976 cb750 used the same style carbs. There were several changes in those years internally and there are numbers stamped on the carb bodies to identify them.(see the attached picture, looking down from the top of the carbs)

http://forums.sohc4.net/index.php?topic=88408.0
So what do you mean by "early style"???
69-71 carbs used a 4into1 throttle cable compared to the 72-76 push/pull 2 cable throttle setup.

Picture would be helpful on your part.
I'll attach my 75 K5(blue) to show you the carbs and a 72(gold) to show the carbs look the same style. One major difference is that the petcock is on opposite side of the tanks on 72-74 than the 75-76 bikes and the 72-74 have 2 fuel lines from the petcock to the carbs compared to a single fuel line from the petcock(has a fuel tee between the #1&2 carbs) on the 75-76 bikes.
 

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