Author Topic: HondaMan ---> CB750F Engine Serial #... help needed (Read 8687 times)

Thor's Hammer! · « **on:** July 29, 2009, 08:15:52 PM »

Hey Guys,

Just brought home my new 78 CB750F and am excited to find out what I ended up with in my purchase.

Bear with me as I know next to nothing of these bikes other than and i am just beginning my research.

I did search but didn't find anything regarding engine versus chassis serial #'s.

My engine serial starts with CB750E-3 and has a single cam "hump" and the cam/valve covers are stamped OHC.

Should my CB engine and chassis match if the engine is the original??

Is there a serial # reference or link explaining the relationship between frame/engine and head tube plaque #'s

Thor's Hammer! · « **Reply #1 on:** July 29, 2009, 08:28:34 PM »

Here a pic of my new project

bikebitzofvt · « **Reply #2 on:** July 29, 2009, 08:30:40 PM »

Here's a chart of the 750F frame & engine numbers from the "website" section of the site. Tons of useful info about your bike can be found there, as well as in the forums.

Model Year Frame # Engine #
750F0 1975 CB750F-1000002 - CB750FE-2500004 -
750F'76 1976 CB750F-2000003 - CB750FE-2515094 -
750F'77 1977 CB750F-2100011 - CB750FE-2600004 -
750F'78 1978 CB750F-2200001 - CB750FE-3100001 -
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ taken from here:

http://www.sohc4.net/index.php?q=content/model-guide-0

Honda engine & frame numbers won't match. I was told by an old Honda wrench that engines and frames were built seperately and they commonly pulled engines from the assembly line for testing, never confirmed it though...

Using the chart above it would seem you have a "K" engine.

Good luck, and welcome to the world of Single Over Head Cam Honda four cylinders!

Thor's Hammer! · « **Reply #3 on:** July 29, 2009, 08:33:55 PM »

Thanks Bikebitszofvt!

I just searched again and found this post...I should have looked more I guess:

http://forums.sohc4.net/index.php?topic=54794.0

Thor's Hammer! · « **Reply #4 on:** July 30, 2009, 11:28:23 AM »

Quote from: bikebitzofvt on July 29, 2009, 08:30:40 PM

Here's a chart of the 750F frame & engine numbers from the "website" section of the site. Tons of useful info about your bike can be found there, as well as in the forums.

Model Year Frame # Engine #
750F0 1975 CB750F-1000002 - CB750FE-2500004 -
750F'76 1976 CB750F-2000003 - CB750FE-2515094 -
750F'77 1977 CB750F-2100011 - CB750FE-2600004 -
750F'78 1978 CB750F-2200001 - CB750FE-3100001 -
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ taken from here:

http://www.sohc4.net/index.php?q=content/model-guide-0

Honda engine & frame numbers won't match. I was told by an old Honda wrench that engines and frames were built seperately and they commonly pulled engines from the assembly line for testing, never confirmed it though...

Using the chart above it would seem you have a "K" engine.

Good luck, and welcome to the world of Single Over Head Cam Honda four cylinders!

I am confused after looking at the thread I found and the guide you kindly posted for me.

My engine serial # starts CB750E-3 something...(I am at work and can't look to get it all).

How does this make it a K motor?

All the engine codes show CB750FE-XXX...is the 5th digit "either" an "F" or an "E"? Just don't understand how you arrived at the engine being a K-model.

Thanks

Sorry, I warned I was new at this

Gordon · « **Reply #5 on:** July 30, 2009, 12:05:29 PM »

Quote from: mismith356 on July 30, 2009, 11:28:23 AM

How does this make it a K motor?

Because all 750F engine numbers start with "CB750FE". 750K engine numbers start with "CB750E". If your engine number starts with "CB750E-3" then you have a K8 engine.

Thor's Hammer! · « **Reply #6 on:** July 30, 2009, 12:39:40 PM »

Quote from: Gordon on July 30, 2009, 12:05:29 PM

Quote from: mismith356 on July 30, 2009, 11:28:23 AM

How does this make it a K motor?

Because all 750F engine numbers start with "CB750FE". 750K engine numbers start with "CB750E". If your engine number starts with "CB750E-3" then you have a K8 engine.

Thanks Gordon!

I just found the details for the K8...

http://www.sohc4.net/index.php?q=content/model-guide-2

I wonder if my carbs are from a K8 motor....in my project thread, somebody mentioned my carbs were wrong for an SS.

http://forums.sohc4.net/index.php?topic=55875.0

I search around...might explain why my carbs aren't correct for a CB750F.

Thor's Hammer! · « **Reply #7 on:** July 30, 2009, 06:17:14 PM »

My full engine serial # is:

CB750E-3106365

Head Tube /Yoke serial is:

CB750F-2206394

This site here seems to think this is the F3 engine:

http://hondachopper.com/modifications.html

I noted in the K8 specs, the serial # show CB750E-30XXXXX

Can anybody confirm this?

Thor's Hammer! · « **Reply #8 on:** July 30, 2009, 07:07:57 PM »

Anybody?

Really wanting to find out what engine I have in this thing.

Any exhaustive or comprehensive list out there I could look at?

Any help really appreciated.

Thor's Hammer! · « **Reply #9 on:** July 31, 2009, 08:18:34 AM »

87 views and only 2 responses...bummer man

super pasty white guy · « **Reply #10 on:** July 31, 2009, 09:32:37 AM »

This is of interest to me as well, since my frame says 750F, but I've swapped out more K parts on there than I care to mention. It makes me feel a bit thick, but I'm still unsure whether my engine is a F or a K.

I've also read different things about the FE versus E- On hondachopper (I think) they state that an F series bike could have either engine number.
http://www.hondachopper.com/engine/engine_mods/modifications.html

but the list given at Z1 doesn't indicate this.

CB750 736cc 4-cycle SOHC four - Super Sport [more]
1975 CB750F
- Frame: CB750F-1000002 - Engine: CB750FE-2500004 [more]
1976 CB750F
- Frame: CB750F-2000003 - Engine: CB750FE-2515094 [more]
1977 CB750F
- Frame: CB750F-2100011 - Engine: CB750FE-2600004 [more]
1978 CB750F
- Frame: CB750F-2200001 - Engine: CB750FE-3100001 [more]

The racing version of the CB750

CB750 736cc 4-cycle SOHC four [more]
1970 CB750
- Frame: CB750-1000001 - Engine: CB750E-1000001 [more]
1971 CB750K1
- Frame: CB750-1044650 - Engine: CB750E-1044806 [more]
1972 CB750K2
- Frame: CB750-2000001 - Engine: CB750E-2000001 [more]
1973 CB750K3
- Frame: CB750-2200001 - Engine: CB750E-2200001 [more]
1974 CB750K4
- Frame: CB750-2300001 - Engine: CB750E-2300001 [more]
1975 CB750K5
- Frame: CB750-2500001 - Engine: CB750E-2372115 [more]
1976 CB750K
- Frame: CB750-2540001 - Engine: CB750E-2428762 [more]
1977 CB750K
- Frame: CB750-2700009 - Engine: CB750E-2700001 [more]
1978 CB750K
- Frame: CB750-2800001 - Engine: CB750E-3000001 [more]

spwg

Gordon · « **Reply #11 on:** July 31, 2009, 09:35:41 AM »

Quote from: mismith356 on July 31, 2009, 08:18:34 AM

87 views and only 2 responses...bummer man

You want people to respond if they don't know the answer?

Thor's Hammer! · « **Reply #12 on:** July 31, 2009, 02:38:41 PM »

Hey Gordon.

Sorry bro...I don't mean to sound like a dick. Was only hoping to find out more info on this motor and thought that somebody would be able to explain the CB750E-310XXX motor serial # and help confirm or deny what i have here for a motor.

I appreciate the answers I have received, just looking for more info.

a TTT or BUMP might work better next time.

thanks again!

Mike

Gordon · « **Reply #13 on:** July 31, 2009, 05:31:05 PM »

Cool. All I have to go off of is the model guide on the sohc4 website. This is the first I've heard of some F engines showing "CB750FE" and others only showing "CB750E", but then I've never had an F so it's not something I've had the need to look into. Hopefully somebody who's run into this before will chime in.

Zaipai · « **Reply #14 on:** July 31, 2009, 05:42:17 PM »

Perhaps a quick PM to Hondaman could clear things up for you. He IS the man on these forums.. Just a idea..

Thor's Hammer! · « **Reply #15 on:** July 31, 2009, 06:39:08 PM »

Thanks Fellas!

I changed the thread title

...always feel weird PM'ing peeps I haven't talked to yet.

super pasty white guy · « **Reply #16 on:** July 31, 2009, 08:03:56 PM »

Also, there's this thread which may, or may not, clear things up.

Oh, PM Hondaman. He'll be glad to help if he can.

spwg

Thor's Hammer! · « **Reply #17 on:** July 31, 2009, 08:26:08 PM »

PM sent to HondaMan.

Thanks guys.

HondaMan · « **Reply #18 on:** July 31, 2009, 09:07:48 PM »

Sorry, guys, when it comes to the late K7/K8 and the "F" series, I'm out of my league. I'm best at the 750K0-K6, the 500, and some on the 550 series. The "F" and "late K" engines were very similar to each other, and were different in several ways from the earlier design. But, there once was a full serial number reference here once: I think it may have been lost in our site crash a couple of years ago (2007, wasn't it?). I haven't looked at it since then, couldn't find it just now.

Thor's Hammer! · « **Reply #19 on:** July 31, 2009, 09:11:09 PM »

Thanks HondaMan! I appreciate you taking the time to reply.

Oh well...I'll keep digging. It's a project, so it is what it is

Clyde · « **Reply #20 on:** August 02, 2009, 06:51:53 PM »

The subject of F vs FE has come up before and we have not seen a definitive explanation. I thought it related to geography, but it appears the US got both.

A CB750K8 should have an engine number from 3000001 to 3062980
A CB750F3 should have an engine number 3100001 to 3157915

Looking at your numbers it it is (IMHO) a 1978 F3 about number 6365 of the production line and the engine is 6394 of the production line.
This would make it a early model, probably produced in the first two months of that 78 model, which would probably date it late 77.

BTW This is about as close as the numbers get

Bill/BentON Racing · « **Reply #21 on:** August 02, 2009, 07:00:16 PM »

Engine serial # CB750FE-3100001-,this the starting engine # for CB 750F'78 Super Sport,Bill

turkey4me · « **Reply #22 on:** August 02, 2009, 08:16:36 PM »

I am not sure if this helps but I purchased a bike from a reputable builder who swears the motor is an F3 but the S/N reads CB750E - 3111288. K8 or F3

??

Bill/BentON Racing · « **Reply #23 on:** August 02, 2009, 08:36:15 PM »

K8,CB750E-3000001- engine starting #,Bill

Thor's Hammer! · « **Reply #24 on:** August 02, 2009, 10:00:04 PM »

Awesome fellas!!

It's nice to have some confirmation on the motor being an F3. I just wish the model info tables quoted here reflected this information.

Thanks again guys!!

Bill...you're two for two man!

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Author Topic: HondaMan ---> CB750F Engine Serial #... help needed (Read 8687 times)