Topic: Confused about CB750 model designations

[postoak]

The Wikipedia article on the CB750 shows this:

1969 - K0
1970 - K1
1971 - K2
1973 - K3

Notice how they skipped 1972, thus aligning the model year to the model number?  But right down below that they have 1972 production figures and if you look on youtube you see references to "1972 K2".  What's going on here?  Is the 1975 a K6 or a K5, for example?

[ekpent]

Technically I believe the 1969/sandcast is just called a CB750. Some questions whether a 1970 was actually listed as a K0 or a way for people to designate a 1970. As far as I know a 1971 is a K1-1972 K2 right up through the years. K5 for instance is a 1975.

[seanbarney41]

also...so the k0-6 are based on build dates, which don't necessarily correspond with western model years...lots of k1's built in 70 AND 71, started k2 production in 71...etc.

[seanbarney41]

also...often bikes would not sell for a few years and not get titled until they sold.  So you often find k3 that did not sell until '75 listed on a title as a 75 model, for example.

[seanbarney41]

good info by serial number here...
www.sohc4.net/cb750k-model-guide/

[CycleRanger]

Technically the "K2" was produced for three or four years for the export market. (Europe etc.)
I believe only North America got the K3-K5.
Or something like that, I'd have to get the book out to be more precise.
That probably accounts for the Wikipedia description.

[postoak]

Okay, the K numbers were sometimes produced over multiple years and other times two different K numbers were produced in a single calendar year. 

But when these bikes came into U.S. dealer showrooms were they officially stated to be a certain year model, or was it just an unofficial thing?  Because if it was official then there should be a strict connection between K number and model year.

[kmb69]

Technically I believe the 1969/sandcast is just called a CB750. Some questions whether a 1970 was actually listed as a K0 or a way for people to designate a 1970. As far as I know a 1971 is a K1-1972 K2 right up through the years. K5 for instance is a 1975.

That is correct. Back in the day, the K1 was the first official "K" designation. Honda called the Sandcasts and the "K0"s just CB750 initially. The K0 was applied later to differentiate the Sandcast and diecast models pre K1.

Okay, the K numbers were sometimes produced over multiple years and other times two different K numbers were produced in a single calendar year. 

But when these bikes came into U.S. dealer showrooms were they officially stated to be a certain year model, or was it just an unofficial thing?  Because if it was official then there should be a strict connection between K number and model year.

There is a strict connection between K models and build dates except for the non-US K2's as CycleRanger states.

also...often bikes would not sell for a few years and not get titled until they sold.  So you often find k3 that did not sell until '75 listed on a title as a 75 model, for example.

seanbarney41 is correct. This practice was stopped sometime in the mid seventies but I am not sure what year. So you could have a K2 for example, titled in 73 and called a 73. But the manufacturing date and serial number on the VIN tag will correctly identify it as a K2.

[postoak]

I'm still not understanding.  When Honda came out with a different K model did they or did they not describe it as being such-and-such model year?

Or, did they just push out CB750s without giving them a model year?

[CycleRanger]

Yes dealers and the sales literature advertised them by model year however very little changed most years other than available colors.

[kmb69]

I'm still not understanding.  When Honda came out with a different K model did they or did they not describe it as being such-and-such model year?

Or, did they just push out CB750s without giving them a model year?

Honda started applying VIN tags with the manufacturing date on the "K0" models. Honda used the K? designation to differentiate the changes that were roughly associated with "year models". IMHO, HONDA did not care so much about the model year like automobile manufacturers do until the US Government forced the issue mid seventies.

[postoak]

Yes dealers and the sales literature advertised them by model year however very little changed most years other than available colors.

And they didn't describe a single K number as being more than one model year did they?

If the answer to that is "no" then I don't see how there could NOT be a very strict correlation between K number (or complete lack there of as in the case of the '69s) and model year.

The only exception to that would be if there were retroactive changes, such as the '69s had no K number but were later given the K0 designation (along with the 1970 models).

[kmb69]

Yes dealers and the sales literature advertised them by model year however very little changed most years other than available colors.

And they didn't describe a single K number as being more than one model year did they?

If the answer to that is "no" then I don't see how there could NOT be a very strict correlation between K number (or complete lack there of as in the case of the '69s) and model year.

The only exception to that would be if there were retrospective changes, such as the '69s had no K number but were later given the K0 designation (along with the 1970 models).

The answer is "no". They were K1 - 1971, K2 - 1972, and so on except for the K2's that were exported for several years to countries other than the US.

The WIKI is wrong!

[CycleRanger]

And they didn't describe a single K number as being more than one model year did they?

Only North America got the K3-K6 so only in North America would k3-K6 strictly correspond to model years.

As Kmb69 says, technically the Wiki is wrong.
 

[Jerry Rxman Griffin aka MuthaF'er]

Then there was the K0 Super Sport as described in Honda parts systems. aka 1975 cb750F.

[kmb69]

Then there was the K0 Super Sport as described in Honda parts systems. aka 1975 cb750F.

Yep, Honda used the "K" designator to specify the technical model as opposed to year model per se. It just works out the way it does for the K1-K8 IMHO. Then they applied "F" to the later Super Sports and did not use any designator other than year model, AFAIK, to the Automatics. They were all CB750A's without any other model identifier and they were pretty much the same bike technically except for the parts that changed aligned with the K6, K7, and K8 production. They did change paint schemes and wheels for different years but did not offer a different model designator other than year.

[postoak]

I am updating this thread with the information in that link pointed to by Sean so as to have a handy reference:

CB750K0 - 1969-1970 (kind of vague compared to later K numbers) (53400)

CB750K1 - August 1970 - November 1971 (15) (77,000)

CB750K2 - November 1971 - September 1972 (12) (63,500)

CB750K3 - September 1972 - June 1973 (9) (38000)

CB750K4 - June 1973 - May 1974 (11) (60000)

CB750K5 - May 1974 - December 1974 (7) (35000)

CB750K6 - December 1974 - June 1976 (18) (42000)

CB750K7 - June 1976 - May 1977 (11) (38000)

CB750K8 - May 1977 - May 1978 (12) (36000)

And doing the math, I've put number of months production in parenthesis after each "run" followed by production numbers.

[Jerry Rxman Griffin aka MuthaF'er]

The 1975 CB750 K0 Super Sport ran from 1/75 to 4/7/1975. CB750F-1000002 to CB750F-10015054.

[Stev-o]

I am updating this thread with the information in that link pointed to by Sean so as to have a handy reference:

CB750K0 - 1969-1970 (kind of vague compared to later K numbers) (53400)

As stated above the first 7414 were not designated K0, but are Sandcast [motors]


Now I have a question about one of my bikes.  The VIN plate states a build date of 7/70, number 1044665. Hondachopper shows it as a K1, but SOHC4 a K0!  What gives??
I'm not a choppa guy, but a lot of you guys refer to them for some info.

http://www.hondachopper.com/engine/engine_timeline/timeline.html
http://www.sohc4.net/cb750k1/

[postoak]

The 1975 CB750 K0 Super Sport ran from 1/75 to 4/7/1975. CB750F-1000002 to CB750F-10015054.

I thought the Super Sport was the same thing as the F model.  (?) And is there such a thing as a K0 Super Sport?

[CycleRanger]

Now I have a question about one of my bikes.  The VIN plate states a build date of 7/70, number 1044665. Hondachopper shows it as a K1, but SOHC4 a K0!  What gives??
I'm not a choppa guy, but a lot of you guys refer to them for some info.

http://www.hondachopper.com/engine/engine_timeline/timeline.html
http://www.sohc4.net/cb750k1/

According to Haycock you have a K1, just barely.
In his book it says K1 from frame #1044650, Engine # E1044806
Released 9/21/70
The Duckworth book gives the same date with no numbers.

HOWEVER, according to the Wyatt book you have a K0.
This is because the two authors differ in their definition of a K0.
And this is probably why internet sources differ.
Personally I would go with the Haycock numbers.
I think there's a bit of supposition in the Wyatt book.

I would think you'd have to tally the "K0" features vs. the "K1" features on your bike and decide for yourself.

I would also like to add that I'm super pissed they reprinted the Wyatt book as I paid a fair bit for my original copy.

Before you buy bikes - buy books. 

[seanbarney41]

The 1975 CB750 K0 Super Sport ran from 1/75 to 4/7/1975. CB750F-1000002 to CB750F-10015054.

I thought the Super Sport was the same thing as the F model.  (?) And is there such a thing as a K0 Super Sport?

you are correct, not sure what Jerry is getting on about now

[Stev-o]

Now I have a question about one of my bikes.  The VIN plate states a build date of 7/70, number 1044665. Hondachopper shows it as a K1, but SOHC4 a K0!  What gives??
I'm not a choppa guy, but a lot of you guys refer to them for some info.

http://www.hondachopper.com/engine/engine_timeline/timeline.html
http://www.sohc4.net/cb750k1/

According to Haycock you have a K1, just barely.
In his book it says K1 from frame #1044650, Engine # E1044806
Released 9/21/70
The Duckworth book gives the same date with no numbers.

That's what I thought all along but my build date is 7/70.   
And my title states 1970 but that was my doing!

I prefer to go K0 but will have to see if it has enough K0 bits or if I am willing to buy them when I restore it this winter. 

[Jerry Rxman Griffin aka MuthaF'er]

The 1975 CB750 K0 Super Sport ran from 1/75 to 4/7/1975. CB750F-1000002 to CB750F-10015054.

I thought the Super Sport was the same thing as the F model.  (?) And is there such a thing as a K0 Super Sport?

Yes, that is correct. Honda listed/termed the first F's as K0 Super Sports. The young kid at one of the locals Honda shops argued with me one day that there was not a 1975 Honda CB750F when he tried looking up a part on their microfiche. What he saw was K0 Super Sport. Not widely used though.

[robvangulik]

Actually the K5 was the 750 with the least amount of horsepower in the whole series, so how about "supersport"?
The F and F1 supersports were the first after a long time listed by Honda with the original 67 hp again, and when actually tested on a bench were found to have 70+ hp, and the F2 came out even better.
I'll see if I can find the magazine article stating this tomorrow, it'almost 1 in the morning here now, and I've had a busy day at a classic bike festival today, with the right kind of weather, so I've had it for the day

[ekpent]

  This 'true horsepower' chart shows the early CB750 at around 48-50 real horsepower which is probably around the 'real' average of these bikes,maybe a little higher in the 50's. Those published figures back then by the factory were on the optimistic side or taken off the crankshaft I think. There are a few guys with some dyno runs around here and am sure Hondaman or Mriek could clue us in well on actual stock hp numbers and some more data after a little modification.  http://www.factorypro.com/dyno/true1.html
  Here is a dyno thread with those worthless pesky photobucket blank pictures thrown in for fun    http://forums.sohc4.net/index.php?topic=83748.0

[CycleRanger]

Steve-o that Sept. date is probably the date Honda announced the availability of the K1, not the actual start of production so considering lag time your July production date is probably in line with Haycock's numbers.

What he saw was K0 Super Sport. Not widely used though.

Here's a K0 Super Sport. 

[kmb69]

The 1975 CB750 K0 Super Sport ran from 1/75 to 4/7/1975. CB750F-1000002 to CB750F-10015054.

I thought the Super Sport was the same thing as the F model.  (?) And is there such a thing as a K0 Super Sport?

Official parts manual calls it a F. The 76 was F1, the 77 was F2, and the 78 was F3 according to the last parts manuals. Jerry bought his new in 1975. Maybe his owners manual could substantiate his claim. I will look through my shop/parts manual collection tomorrow to see if I can find anything.

[Jerry Rxman Griffin aka MuthaF'er]

Don't think I have anything in print. My HC43212 P8175 Honda 1st edition parts manual dated 1975 states CB750F and CB750F-76 on the cover. I just remember working with the parts kid at Apex Sports here in Colorado Springs when he said he couldn't find a 1975 CB750F on his computer/microfiche. I've been here for 18 years so I can't say for sure when this was. Many moons ago. I told him I had one and knew what I was talking about. He turned his screen around for me and showed me the 1975 K0 Super Sport designation when I told him I could help him.

[scottly]

In the early '80s I was working with a fellow from Japan, who was helping Beta test his company's newest system, dubbed "Kai" (rhymes with eye). When I asked him what Kai meant, he thought for a couple of seconds, trying to think of the English word, and responded "new.. improved." I believe that the K is short for kai, and refers to a version or upgrade. It's just coincidence that the 750 K numbers coincide with the year model, unlike some other Hondas.

[seanbarney41]

Jerry, when has a kid at the parts counter at a dealership ever known jack #$%*?

[PeWe]

Europe got K0, K1, K2, K6 and K7. No K3, K4, K5, K8, F3, maybe no F0 either.
F bikes... I have only seen and heard about F1 and F2.
I have a K2 titled 1975 which look more as a US K1. The cases I use for the build is K2 engine and has marks to have used the single row ball bearing on the final shaft. Case can use the later double row ball bearing which it will get. Different shaft though.
My K2 will get the old style grab bars, later got one bar that goes all the way around the rear part of seat, fastened as the 2 single bars, shock upper bolt and rear fender/blinker bolt.
 
Most K6 here has title year 1977 as mine despite it was built Q3 -76 and got registration October 1976.

Important to see and know the differences of the engine internals. K6 has different clutch, outer fiber plate has wider tabs. Clutch basket look different and is fastened to the shaft thru primary hub with a clip and different spline washer. Later engines got deeper clutch hub and a double riveted metal disc.  The clutch cover is different to handle the thicker package. I think that the only CB750 in Europe with that clutch is F2. Clutch fibers same as the K6 though.

The USA bikes got different rear lamp K2 and blinkers K5 according to CMSNL charts.

European K2, K6 bikes have the old blinkers and rear lamp as K1. This need the old type of rear fender. I found a NOS rear fender to my K6...bought as K1 with correct holes for rear lamp. My K6 had a mudflap fastened with 5 screws in rear fender. I have not seen those fenders as spare. K1 that fit has only 1 hole. I found some NOS mudflaps in  France last year.

Hondaman has described the differences of timing, cams, carbs and hp. First CB750 had 67hp on crank, later 63hp.  Some guys have written about 50 on rear wheel.  F2 got over 70, maybe 73 hp on crank.
CMSNL spare part charts show some details but not correct rear fender stuff for my euro K6, it has US styke with big lamp and 3 additional holes on fender for the support of lamp.  https://www.cmsnl.com/honda-cb750four_model14344/

There are more details to be aware of

[kmb69]

In the early '80s I was working with a fellow from Japan, who was helping Beta test his company's newest system, dubbed "Kai" (rhymes with eye). When I asked him what Kai meant, he thought for a couple of seconds, trying to think of the English word, and responded "new.. improved." I believe that the K is short for kai, and refers to a version or upgrade. It's just coincidence that the 750 K numbers coincide with the year model, unlike some other Hondas.

I agree. I bought a new CB450 K2 in 1969.

[Don R]

 I think the waters get muddy because American Honda would issue new titles for leftover bikes. My cb500K2 was sold as a k3 in 1973. The dealer assured me it was the latest model and not last years leftover. He was being less than accurate. Later Honda sent me a check for $37 due to a class action lawsuit from New York state.
 That was settled in 75 and Honda went into production of 76 models early to prove a point. That's why there are fewer 75 models and a lot more 76's.
 

[kmb69]

I think the waters get muddy because American Honda would issue new titles for leftover bikes.
.....

Close, but not exactly. Prior to the class action lawsuit, American Honda issued a MSO - Manufacturers Statement of Origin WITHOUT a year model assigned. The states in which they were sold, converted the MSO's into titles. The titles then showed the model year as the year they were titled. Subsequent to the class action lawsuit, American Honda was forced to issue their MSO's with a year model and the states then titled them to match the year model on the MSO.