Topic: Frame year different than title

[Mticar1]

I was reading how some of the early CB750s have early frames with later model years, ie. a k2 frame number with a title that says its a 1973.  I have a 1973, so I checked it, my frame number is CB750-1009821, the engine number plate is blank, but after some research I believe I have an early K3 motor, with the "extra" fin supports.  When I look up the frame number it comes up as 1969/1970, but I'm not sure because everything I found has the starting frame number but not the end of run frame number. And like I said the title says 1973 and the vin matches the title, is it possible it's K1 or K0 frame?  Does it make a difference?  Should I be concerned?
Thank you for any help

[Don R]

 In some areas the bike was titled the year it was sold, one possibility. American Honda often sent new titles for previous year bikes. The blank engine plate is on a replacement case.

[jlh3rd]

so, a common misconception concerning honda, especially with new people is that honda always designated model years. Not true. That didn't start officially until 1974. Prior to that , it was a model number with a sell/release date.
    Hence the confusion sometimes with a title, as some places made the date a bike was sold as the "model" year. You could see this happening with left over or late release date bikes.
     Your frame is a CB 750KO , released 06/06/69....very important.
If the engine vin plate is blank, then that is a replacement case that appears to have not been dealer stamped. All Honda replacement cases were unstamped from the factory.
      Yes, it's very important in your case, value wise. It would be of interest for you to see what that engine is.
Lots of 750 experts on here.

[jlh3rd]

what color is the bike...pics?....many early model 750's had engine cases replaced due to chain breakage which knocked a hole in the case........so...very curious...

and, the first 750's sold weren't even known as KO's...just CB750.....honda added that in hindsight....
I think sandcast experts are needed here.

[Stev-o]

is it possible it's K1 or K0 frame?  Does it make a difference?  Should I be concerned?

Yes, sounds like you have a K0 frame and the motor was a replacement, possibly from a broken chain that cracked the case in the front sprocket area, fairly common.  If the dealer replaced the motor, they were to resamp the replacement motor, obviously that did not happen in your case, also fairly common.

What is the condition of the bike? With a matching motor, you would have a very valuable bike. Your bike came with a "Sandcast" motor, there were only 7414 made, then they switched to diecast for the rest of the run.  Here is a good explanation...

https://www.hagerty.com/media/motorcycles/why-do-collectors-pay-double-for-a-honda-cb750-engine-cast-in-sand/

[Mticar1]

I'm pretty sure its a k3 motor.  The bike was pretty beat up when i got it.  The wiring harness was speaker wire and wire nuts, the generator wires were melted, the license plate on the bike expired in 1984.  I got the bike from my BIL, he collects old Japanese bikes(and a couple old Bultacos), he bought about 50 from an old out of business bike shop, I helped him move them and he gave me the bike for helping.  I don't believe thats the original gas tank, but the underside is red/maroon, the two side covers are also black. 

[ekpent]

 Some states I believe and Wisconsin being one I think titled the bike by the numbers on the engine to further confuse things. Might of had a 73 engine at one time ? Your bike does have an early oil tank. When you open your gas cap on the tank do you see wrinkles in the metal ? Lot of other later model possible 73 parts on it also.
  Can you post a pic of the vin plate if it has one on the frame and the stamped serial number so we can see the style of the script.

[Bankerdanny]

is it possible it's K1 or K0 frame?  Does it make a difference?  Should I be concerned?

Yes, sounds like you have a K0 frame and the motor was a replacement, possibly from a broken chain that cracked the case in the front sprocket area, fairly common.  If the dealer replaced the motor, they were to resamp the replacement motor, obviously that did not happen in your case, also fairly common.

What is the condition of the bike? With a matching motor, you would have a very valuable bike. Your bike came with a "Sandcast" motor, there were only 7414 made, then they switched to diecast for the rest of the run.  Here is a good explanation...

https://www.hagerty.com/media/motorcycles/why-do-collectors-pay-double-for-a-honda-cb750-engine-cast-in-sand/

That frame number would likely place it outside of the Sandcast range wouldn't it?

[Stev-o]

is it possible it's K1 or K0 frame?  Does it make a difference?  Should I be concerned?

Yes, sounds like you have a K0 frame and the motor was a replacement, possibly from a broken chain that cracked the case in the front sprocket area, fairly common.  If the dealer replaced the motor, they were to resamp the replacement motor, obviously that did not happen in your case, also fairly common.

What is the condition of the bike? With a matching motor, you would have a very valuable bike. Your bike came with a "Sandcast" motor, there were only 7414 made, then they switched to diecast for the rest of the run.  Here is a good explanation...

https://www.hagerty.com/media/motorcycles/why-do-collectors-pay-double-for-a-honda-cb750-engine-cast-in-sand/

That frame number would likely place it outside of the Sandcast range wouldn't it?

You are correct Danny, my mistake.  [for some reason I was thinking 14,000]

[seanbarney41]

I see unicorn top triple...that is from 72 or earlier...your bike is a bitsa, bits of this, bits of that.  You have lots of research to do in order to figure out what bits are from what

[Stev-o]

he bought about 50 from an old out of business bike shop

He bought 50 bikes?!  Holy #$%*e!  He's got Eric beat....

[Mticar1]

My BIL has upwards of 300, its his retirement plan, rebuild them and sell them, he's not good at sitting still. 

I started down this road because I was looking on ebay for a front caliper and disc to do the dual disc conversion, and the seller said some 1973 bikes had k2 front forks and some had k3, and the brackets are different.  I looked at some parts diagrams, and I'm pretty sure its a k3 front end.  The title says 1973, and the engine looks like an early k3, I think its just the frame that's not k3.

[ekpent]

 Just to clarify is the number on the title the number that is stamped on the frame ?
  Looks like a 71 or earlier tailight.

[Mticar1]

yes

[ekpent]

What state is the title from ? Back in the day in Michigan they used to play pretty loose getting a lost title for any bike. Not so much now.  BIL means brother in law ??

[dusterdude]

My 750 is a august 71 build k1 but titled as a 72

Sent from my LM-G850 using Tapatalk

[Mticar1]

Yes BIL is brother-in-law
It was titled in Illinois, but the title was dated 1998, but the tags for the bike expired in 1984.  I believe the bike was abandoned at the bike shop sometime in 1984, then the story I was told is someone started buy up old bike shops for the inventory.   The bike was "sold" in 1998, I'm guessing to the bike shop buyer, who when he got all the inventory spent sometime getting titles for all the bikes.  Anyway, my BIL got all the bikes 3 or 4 years ago, I helped move them and I got the bike.  I live in Maryland and I just went to the MVA today to title and tags. The MVA had no issues, gave me a tag, and I was on my way.

[jlh3rd]

according to this, it appears your engine is earlier............K3 or lower....curious just  how early...
It's not sandcast status....but it's a KO.....what are your intentions?
    The thing is, practically everything for that bike can be purchased new....tank, covers, pipes, wheels, airbox, .....not cheap........but a few good options for you, i'd think..

[MrOuija]

My CB550 has a build date 12/74 on the frame plate, but my title says it is also a 74 year model. Not sure what happened there.

[754]

You have a 69/70 oiltank, and that matches frame number. Your forks are73 or later as are your instruments. .
 There is an easy way to tell if that motor came with that frame. (And had cases changed)..
 Look in front of 2 and 3 plugs, is there a bolt between the two plugs but on the top fin, rear part of fin? I can sort of see in your pic, its not clear so I am not sure ? It appears no bolt., if that is true, then the head  is no later than Feb 70, and real good chance its the original motor.
 You are correct though, early 73 they still used that style of head but with center bolt.

[Kevnz]

My CB550 has a build date 12/74 on the frame plate, but my title says it is also a 74 year model. Not sure what happened there.
[/quot According to the numbers, my 550 had a 1974 frame, 1976 engine, and was registered new in 1980 as a 1977. 1977 was first year of the 550K, but by 1980 there was plenty of more sophisticated competition around; would have been a hard sell.

[seanbarney41]

I see unicorn top triple...that is from 72 or earlier...your bike is a bitsa, bits of this, bits of that.  You have lots of research to do in order to figure out what bits are from what

oops...that is not unicorn top triple.  I will get off the crack now.

[Mticar1]

It looks like there is a bolt hole between 2 and 3 exhaust ports, but no bolt.  I put a piece of wire down the hole and it seems to go all the way into the block.  Should I put a bolt in there?  Also, I did some research about the different heads and read about the production code stamped in to them between 2/3 intake, but my code doesn't look like any others.  Also I don't know if it means anything, but like I said before, when I got the bike the electrical system was a mess, the wires to the stator were melted, so I had to replace the stator.  When I pulled the cover off the oil galley plug was missing, I bought one on ebay and put it in, should I take it back out?
Thank you to everyone for all the help and info

[DickL]

When I bought my K0, a 3/70 build, five years ago, it had a 1974 motor, I found a matching motor , that was withiin  50 s/n, I sent motor to Hondaman for overhaul and now I have a restored matching number bike.

I would guess that your frame was a November 1969 build or sooner. A very early diecast. If I were you I would be patient and search for a matching S/n engine.

Meanwhile restore the frame to period correct condition. When done you might have something worth 20 to 25K

Dickl

[69cb750]

I would guess that your frame was a November 1969 build or sooner. A very early diecast. If I were you I would be patient and search for a matching S/n engine.

CB750-1009821 was built in October 69.
My 69 diecast is near this vin.

[ekpent]

 I'm still curious if you have the original early 'wrinkle' gas tank or a later one. Even the early wrinkle tanks had differences that can affect value like 2 dimple versus 4 dimple etc..

[754]

 So looks  like later motor...

[jlh3rd]

if there is some way to document what year/model case you have, it could be stamped with a number to go with the frame, as intended and being honest. Of course, you need that old honda dealer with the factory issued stamp set. If it matters to you. Then you wouldn't need another motor.......one thing leads to another....and depends on your intentions.
     Check out honda750expert.com for some good information.

[bryanj]

There never was a factory issued stamp set

[HondaMan]

It looks like there is a bolt hole between 2 and 3 exhaust ports, but no bolt.  I put a piece of wire down the hole and it seems to go all the way into the block.  Should I put a bolt in there?  Also, I did some research about the different heads and read about the production code stamped in to them between 2/3 intake, but my code doesn't look like any others.  Also I don't know if it means anything, but like I said before, when I got the bike the electrical system was a mess, the wires to the stator were melted, so I had to replace the stator.  When I pulled the cover off the oil galley plug was missing, I bought one on ebay and put it in, should I take it back out?
Thank you to everyone for all the help and info

Yes, put the oil port plug back in, with a new O-ring if you can find one. I might be able to come up with one, I'll look around.
The front bolt: if there are the threads in the cylinders to accept it, do put that in: it was added after the K0 to prevent oil leaks that come from crankcase pressures pushing against the thin zone of the head gasket at that point. Only the K0 engines omitted this bolt. If the head is K1-K3 and the cylinders are K0, there will be no hole nor threads in the cylinder's block to hold the bolt in.

About all the "mix" of parts: another possibility is an insurance-funded rebuild of a major crash of a bike. It was not uncommon for folks to fully insure these bikes in the day so that in the event of an accident it could be replaced, or fully rebuilt, at the owner's discretion. I personally aided (or did) several bikes of various kinds in my shop that underwent this activity. For example: if the bike were originally a K3 and the (fully-insured) rider got rear-ended by a car, the frame would have been toast and the chain, going slack from being hit while the rider may have been sitting at a stop with the bike in gear and the clutch pulled in, then doubled over and punched through the engine cases when the surprised rider let go of the clutch lever. So, the insurance would pay for a new or used frame installation and new cases on the engine. This sort of thing was very common then, and lucrative for shops like mine. When all was said and done, the insurance company would certify the bike to the State as an "insurance rebuild" bike and it would retain its original title albeit with the new frame number, regardless of that part's origin.

[BenelliSEI]

When I bought my K0, a 3/70 build, five years ago, it had a 1974 motor, I found a matching motor , that was withiin  50 s/n, I sent motor to Hondaman for overhaul and now I have a restored matching number bike.

I would guess that your frame was a November 1969 build or sooner. A very early diecast. If I were you I would be patient and search for a matching S/n engine.

Meanwhile restore the frame to period correct condition. When done you might have something worth 20 to 25K

Dickl

Or you can have mine for $25K!!

[754]

Oh yes m i forgot, coukd still be a KO cylinder if there is no threads in the cylinder, that would explain missing bolt. . In that case it would mean it may be tge original motor except for cases and geadm if you are lucky.
 The bolt hole being there started somewhere in the 26,××× range.

 Another thing you may see and I have one.... is the hole added to the head that came without the hole..

[Mticar1]

I did replace the galley plug, as for the bolt in the head, does anyone know what size it is?  from the hole size I'm guessing M6, maybe 85mm?

[Mticar1]

And it does have a wrinkle tank

[754]

Yes 6 mm bolt, but first stick a 3/16 or so drill bit in, see how far it goes..

[ekpent]

And it does have a wrinkle tank

Actually I don't think its an early wrinkle. Wrinkles in the wrong place as seen from underneath. If you open the gas cap and look inside and see wrinkles that's good,if its smooth its later. I'll snap a pic or two of one in my basement later.

[newday777]

And it does have a wrinkle tank

Wrinkle tanks have front to back wrinkles looking through the gas cap, not side to side.