Topic: CB7750 engine serial number

[Mark K]

Picked this up over the weekend, confused about what year model engine it is. Checked a couple different websites (and here). I believe it's out of a '76 bike, just want to make sure.

Engine serial # CB750E-2513331

Any help is appreciated,

Thanks,
Mark K

[rotortiller]

That's a funky looking starter cover. 

[69cb750]

CB750E-2513331 is 1975 F engine

[Stev-o]

The model guide shows the engine serial numbers...

http://www.sohc4.com/cb750/cb750f/#serial-numbers

[newday777]

That's a funky looking starter cover. 

Probably was in a chopper and those are start button and???

[Mark K]

That's a funky looking starter cover. 

Along with the toggle switch, there is a key switch, (ignition?) on the starter cover.

[Mark K]

CB750E-2513331 is 1975 F engine

That's what I thought too, but the number doesn't fit into the model guide, (Stev-o posted a link), I had looked there, but because the number didn't fit, I thought I'd ask the experts here.

[Mark K]

The model guide shows the engine serial numbers...

http://www.sohc4.com/cb750/cb750f/#serial-numbers

Thanks Stev-o, I had looked at the guide and the number didn't "fit" in the range of numbers.

[Mark K]

Probably was in a chopper and those are start button and???
[/quote]

Not sure what it came out of, guy I bought it from found it in a building he was cleaning out for a friend. He didn't have any history on the engine.

[69cb750]

That's what I thought too, but the number doesn't fit into the model guide, (Stev-o posted a link), I had looked there, but because the number didn't fit, I thought I'd ask the experts here.

25115085 - 2500004 = 22,615,081 22 million engines !
Chart is incorrect, your engine is in 22 million range.

[HondaMan]

It looks to me like a 1975/6 750F0.

[RAFster122s]

If an F motor then it has some special things to watch out for given the F motor had some teething issues, right?

[Jerry Rxman Griffin aka MuthaF'er]

CB750E-2513331 is 1975 F engine

+1 on the 75 750F engine. Bottom end anyway. Does the head have 392 on the top fin of the head backside between 2 & 3? That would also indicate 75 top end

[Jerry Rxman Griffin aka MuthaF'er]

The model guide shows the engine serial numbers...

http://www.sohc4.com/cb750/cb750f/#serial-numbers

Thanks Stev-o, I had looked at the guide and the number didn't "fit" in the range of numbers.

         Then the guide is wrong

[Jerry Rxman Griffin aka MuthaF'er]

The 75/76 F engine had NO teething issues. It is a good update engine.

[newday777]

If an F motor then it has some special things to watch out for given the F motor had some teething issues, right?

Not the 75/76 F that this thread is about (though the motor could have a later head on it if it was modified at some point in it's lifetime and we didn't get that from this information given)....
77/78 F2 heads, yes(valve guides).

You need to be careful with specific information and not just say F had teething issues.....

[jlh3rd]

Picked this up over the weekend, confused about what year model engine it is. Checked a couple different websites (and here). I believe it's out of a '76 bike, just want to make sure.

Engine serial # CB750E-2513331

Any help is appreciated,

Thanks,
Mark K

from this book, this is what you have
a 1975 750F

[jlh3rd]

 and ...as discussed on here before.
It appears the '75 F model was only around for 2-3 months before the '76 F debut.
makes the bike/ motor kinda ...rare ?

[HondaMan]

If an F motor then it has some special things to watch out for given the F motor had some teething issues, right?

Not the 75/76 F that this thread is about (though the motor could have a later head on it if it was modified at some point in it's lifetime and we didn't get that from this information given)....
77/78 F2 heads, yes(valve guides).

You need to be careful with specific information and not just say F had teething issues.....

The 77F2/78F3 also had extra-strong valve springs with extra-weak top spring retainers, which caused their infamous reputation for 'dropping' a valve when the cotter keys pulled thru the simple stamped-steel retainers. Ken a CycleX has a solution for this issue that I install in every F2/3 head that comes my way: super-strong top spring retainers. Worth every cent.

[Mark K]

It looks to me like a 1975/6 750F0.

Thanks HondaMan.

[Mark K]

CB750E-2513331 is 1975 F engine

+1 on the 75 750F engine. Bottom end anyway. Does the head have 392 on the top fin of the head backside between 2 & 3? That would also indicate 75 top end

Thanks Jerry. I had my son-in-law help unload it and I stowed it under my work table for now. Have to finish up my current project. But I will check for the '392' when I get a chance. My plan is to put the engine in a '73 frame I acquired about a year ago, (future project).

[Mark K]

Picked this up over the weekend, confused about what year model engine it is. Checked a couple different websites (and here). I believe it's out of a '76 bike, just want to make sure.

Engine serial # CB750E-2513331

Any help is appreciated,

Thanks,
Mark K

from this book, this is what you have
a 1975 750F

Thank you, I trie to find that book as a PDF download, no luck.

[Jerry Rxman Griffin aka MuthaF'er]

Mark, I have a spare one under my work bench too 

Just a FYI. The 75 ran from 1/75 through the first week of April. 15054 only. But the engine was the same in 76. A total of ~ 54,000 were produced.

[jlh3rd]

Picked this up over the weekend, confused about what year model engine it is. Checked a couple different websites (and here). I believe it's out of a '76 bike, just want to make sure.

Engine serial # CB750E-2513331

Any help is appreciated,

Thanks,
Mark K

from this book, this is what you have
a 1975 750F

Thank you, I trie to find that book as a PDF download, no luck.

I bought one last year for my son from HELMS. With tax and shipping it ended up around $80.  Last time I checked they still had some.
HELMS is a quality OEM manual manufacturer.

[Mark K]

Mark, I have a spare one under my work bench too 

Just a FYI. The 75 ran from 1/75 through the first week of April. 15054 only. But the engine was the same in 76. A total of ~ 54,000 were produced.

Thanks for the info Jerry.

I have a '70 SL350 I bought about a year ago. Disassembled it and it now resides in a large cardboard box in the garage, except for the frame, wouldn't fit in the box  has a CL350 engine. Need to get started on that one sometime.

[Mark K]

"I bought one last year for my son from HELMS. With tax and shipping it ended up around $80.  Last time I checked they still had some.
HELMS is a quality OEM manual manufacturer."


jlh3rd, thanks for the link!