Topic: 1972 Honda cb750 K2 engine serial numbers

[Old Moe Toe]

Hi Don
The literature I have at hand says K1's started with engine number of 1044806 onwards until the K2's, which started with 2000001 onwards until the K3's.
According to that yours has a K1 engine.
Lucky you! I'd like a K1 engine.
Cheers

[Don R]

 I know, that's what's strange, the bike shows all the signs of being a K2, I'm wondering if it's a transition bike and the engine was a holdover for repairs or a one in a hundred that got dyno tested.

[VTCBike750]

Digging up an old thread.

Just looked at a K2:
Frame 2002424, Engine 2010008

[trigger]

What about the CB750K2's that had frame/VIN numbers starting with 21***** These were sold in the UK in mid 1975 to early 1976 

[PeWe]

What about the CB750K2's that had frame/VIN numbers starting with 21***** These were sold in the UK in mid 1975 to early 1976 

Sweden too. My K2 1975 has 21028xx.
I have full documentation from it was imported by Honda dealer asking for registration July 1975.

[VTCBike750]

I guess my real curiosity lies with my K2, it being lower serial number than Hondamans if my motor is original to my bike.  Which if everyones K2 is around 7000 of I would think Hondamans should be too.   Hondamans K2 frame is 2,004,850 I think?  Mine is 2,004,090

Okay, Mark Paris got back to me about his early K2 engine number.  It is 2012242 which falls into the 7000 number gap between frame and engine numbers.  My frame and his are 440 numbers apart my engine and his are 424 apart which lines up correctly if you take into account the 1 in 10 engines removed for testing.  Which makes my original idea that Honda started the run of K2 engine numbers at around 2007000 and not at 2000000 like specified by honda.  Still hoping to find a low 2000000 engine number out there. i plan on figuring this number deal out so if anyone has any info or memory of this topic please help.... thanks

Forgot to mention that it had a production date of 10/71, earliest Ive seen on a K2.
Frame 2002424, Engine 2010008, Lowest U.S. K2 Ive seen, online or in person.

K1 Engine with an early K2 Engine VIN?
http://www.sohc4.net/cb750k-serial-numbers

[69cb750]

Forgot to mention that it had a production date of 10/71, earliest Ive seen on a K2.
Frame 2002424, Engine 2010008, Lowest U.S. K2 Ive seen, online or in person.

2002424 is #2424 K2
I have seen -
CB750-2001814 build 10/71   CB750E-200071x
CB750-2002436 Build 10/71   CB750E-2010165

[Keith]

My K2 is way off too. Mine is a 11/71 build, I will have to look at the numbers, but I know it is  quite a bit off. Always wondered about that, since I had it since 4,000 miles on it.

[Keith]

My frame #2004208, my engine #2011833. So I am over 7,000 off too. Looks like an early K2 as well, mine has the red side cover emblems....anyone else?

[69cb750]

My frame #2004208, my engine #2011833. So I am over 7,000 off too. Looks like an early K2 as well, mine has the red side cover emblems....anyone else?

11/71 build ?
K2's started aligned but quickly jumped to 7500 engine offset, no idea why.

[CaptFatCat]

My K2 is a 3/72 with 7,355 digits apart.. looks like the engine shop worked a little faster than the frame shop.

[jlh3rd]

Isn't the  honda motorcycle identification guide and it's associated frame and engine numbers for american import bikes only?  There is no identification guide for european bikes ?  So doesn't this add to confusion ?
The identification guide is not error proof.
Isn't the data plate on the frame strictly the frame production date? My 75 550F, like some of your 750's , has a data plate of 12/74...but it's a 75, so the data plate date is somewhat irrelevant? It's the frame # that is relevant? But a motor vehicle registration department could title mine as a 1974 model.....more confusion.
If your frame has no data plate and all you have is the engine number, that number would be the only official " document " as proof of model year. Lots of parts from many years can be interchanged so that doesn't prove what model you have, nor does the title date, unless you are the original owner or have further documentation of the initial purchase.....

[PeWe]

The European bike looked different.
CB750 K2 sold between 1972- 75.
Same look 1975 as 1972 except for cylibder and head. K1 style blinkers, rear lamp and fender. Rhino horn mounted gauges and only one grab rail on left side.

K6 as US bikes except for blinkers, rear lamp and fender that still have K1 style. EU handlebar loer than US.

Headlight had H4 on all of the K2 and K6 as I have understood.

 Rear fender not exactly as K1 that only had 1 hole for rubber mud flap. The Euro bike had 4 oval holes in rhe rear fender for the flap. I have a NOS K1 fender for my K6 as spare. The original version not to be found.

K3- K5 not sold here.

[bryanj]

A bike built in japan 12/74 is not going to be uncrated anywhere till 1975 and in UK it is the date of first rREGISTRATION that counts, alsoit would have been a 75 model anyaay