Topic: Newbie with question about CB750Fx nomenclature

[Holubs]

Apologies in advance if this is a dumb question, but I have searched the site and haven't found (or missed) the answer.  I hear the posters here calling their bikes CB750F1, CB750F2, etc. and wondered how I would determine which I have. 

Is the CB7590Fx nomenclature tied to the first digit of the frame number?  That would make sense to me.

My bike is a 1976 CB750F, that I am in the process of trying to make street worthy again after 15 years stored in a shed on my nephew's dairy farm. 

Just wondered how I could tell which I have.

Thanks,
Holubs

[kghost]

the number you refer to basically corresponds to the year of production....

For example....
1969 was the first year of the "K" bikes...SO thier referred to as a K0 tho Honda never called them that.

1970 falls under the K0 too
1971 would be K1
1972 would be k2
etc.

[Holubs]

So then, I take it the 1975 CB750F a F0 and my 1976 would be an F1?

[cb750fbomb]

So then, I take it the 1975 CB750F a F0 and my 1976 would be an F1?

That's correct. Here's a link to the road test:

http://www.sohc4.net/index.php?title=1975_Cycle_World_Test:_Honda_CB750F0

CB750F Models

    * 1975 CB750F
    * 1976 CB750F
    * 1977 CB750F
    * 1978 CB750F

[Holubs]

Thank you for the info. 

Now I can proudly say I am the owner of an F1!  If I could only say it was running again.....

[Jerry Rxman Griffin aka MuthaF'er]

Welcome to the site.

The 1975 CB750F which Honda refers to as the CB750K0 Super Sport was produced in early 1975. AKA CB750F0. Mine is serial number CB750F-1001606 with a production date of 1/75. 15053 were made in total with the first as CB750F-1000002. The 1976 CB750F was designated as CB750F1 and started production around 5/75 or 6/75. Then came the 1977 CB750F2 and the 1978 CB750F3. There were some differences in availability and parts in different countries. 

Good luck on getting it going. Let us know what you need.  

[upperlake04]

  Welcome Holubs to the SOHC club and a special congrats on being an F owner, the elite of the cb750 tribe. 

 Rxman - do you know the production numbers for the other 750Fs?

[Jerry Rxman Griffin aka MuthaF'er]

UL,

From my Honda Parts Catalogue fiche 4/1993 2nd edition

CB750F '76 frame CB750F-20000003 to CB750F-20022317
engine CB750E-2525094 to CB750E-2563530 (I'm thinking more Honda typos with engine # beginning 2515054 since thats where the 75's left off. These numbers make little sense if the numbers were sequencially correct. Must not have been. 38436 engines with 22314 frames? If you take the last engine number 2563530 and subtract the last '75 engine 2515054 that would give 48,476 '76's produced)
 
From my Honda Shop Manual

CB750F2 frame CB750F-2100001 "and subsequent" (from my shop manual)
CB750F3 frame CB750F-3100002 "and subsequent"


From my Honda Parts Catalogue 1st Edition 1975

CB750F engine 750F-2500001 "to subsequent"  frame 750F-10000001 "to subsequent" (the engine numbers would have actually been CB750E-xxx)
CB750F 76 engine 750F/76-2515094 "to subsequent"  frame 750F/76-2000003 "to subsequent" (the frame numbers would have actually been CB750F-xxx)

This isn't the first times I have seen Honda typos. I've found typos throughout any literature I have including Clymers, Haynes, etc

My conclusion is there is nothing definite from my sources except for the '75.

[Maurizio]

Welcome Holubs to the SOHC club.

The 1975 CB750F which Honda refers to as the CB750K0 Super Sport was produced in early 1975. AKA CB750F0. Mine is serial number CB750F-1001606 with a production date of 1/75. 15053 were made in total with the first as CB750F-1000002. The 1976 CB750F was designated as CB750F1 and started production around 5/75 or 6/75. 

So my June '76, with frame # CB750F-1028xxx is indeed a CB 750 F1...

CB750F '76 frame CB750F-20000003 to CB750F-20022317
engine CB750E-2525094 to CB750E-2563530 (I'm thinking more Honda typos with engine # beginning 2515054 since thats where the 75's left off. These numbers make little sense if the numbers were sequencially correct. Must not have been. 38436 engines with 22314 frames? If you take the last engine number 2563530 and subtract the last '75 engine 2515054 that would give 48,476 '76's produced)

From my Honda Parts Catalogue 1st Edition 1975

CB750F engine 750F-2500001 "to subsequent"  frame 750F-10000001 "to subsequent" (the engine numbers would have actually been CB750E-xxx)
CB750F 76 engine 750F/76-2515094 "to subsequent"  frame 750F/76-2000003 "to subsequent" (the frame numbers would have actually been CB750F-xxx)

Or not?   

[Holubs]

Thanks again for all of the info.

I do have need of a float bowl and drain screw for #2 carb, the drain screw was seized and broke off when I tried to remove it.  The float bowl will complete the carb rebuild.  Any tips on finding a replacement float bowl would be appreciated.

Have been working on the wiring, which was a mess after sitting for so many years.  About the first 12 inches of insulation on the ground wire from the rectifier was melted.  Have replaced the melted wire, but don't know the cause yet.

In general, I'm finding that the manure dust from the dairy farm was corrosive, even though the bike was stored inside.

Holubs

[upperlake04]

 I appreciate the digging for that info Rx. Thanks.

[Jerry Rxman Griffin aka MuthaF'er]

Maurizio,

Honda mixed them up around the world so........  My literature is from the US.

From US standards: your color is '76. I do believe that June '75 was the start of the '76 runs and your June '76 would probably be the end of the '76 run. Your frame would be '75 but '75's stopped at 10015054....... go figure?! Your bike has non-standard turn signals like used in England and not the states. Your front fender is British also with 2 braces instead of 1. Don't you also have different bars and the rear fender guard? ETC. It would be interesting to find some genuine Honda literature on the European models. Perhaps on CMSNL's site? They have listings for European models and others too. The one true deciding factor would be the identification attached to the steering head.

Holubs,

The float bowl should be universal for #1 & #2 up until the pumper carbs on the '77 models. I do not have any spare carb parts but someone here could help. Post a seperate posting for that. Check your rectifier before cranking it up just to be on the safe side. Do a search. It's been a while but it's easy to do with a multimeter. Continuity between terminals on the connector one way but not the other. Reverse polarity or jumping from a car with the engine running (way too many amps from a car alternator)may have melted the ground. These wiring harnesses are VERY difficult to locate. Take care with it. I have seen 2 NOS ones in the past 3 years. Mine cost me $150 2 years ago and one just went for almost that in Australia this past month. I scan EBay daily so I stay pretty much up to date on availability. 

Jerry

[Holubs]

Thanks for the information, Jerry. 

I did take the rectifier apart to clean it and checked the 6 diodes in the pack, looks like they are all OK.  I haven't looked at the regulator yet.  I opened the wiring harness and replaced the ground wire all the way back to the original place it was soldered into the wiring harness.  The rectifier connector was melted and the contacts were shot, so I bypassed it with the wire for now.   I will most likely replace the rectifier (and regulator) with the Oregon units after I get the bike running.

I posted to the parts wanted area about the float bowl/drain screw, received a reply from a very pleasant fellow that had a '77, so wasn't much help.  Have started contacting salvage yards, see what that turns up.

Holubs