Topic: Strange frame serial number

[Timboslice]

Hey guys, I have a cb750 frame, it has a strange serial number that I can't identify. Can anyone tell the year model from this? A guess is 77 but it doesn't gel with the factory codes.

Cheers!

[ekpent]

 Does not look like a stock stamping. Are there any other stampings or signs a plate or decal was ever attached to the neck area ?

[Timboslice]

No that's all that there is on the frame unfortunately...

[Stev-o]

Does not look like a stock stamping.

+1.    My guess was it was stolen at some point, original VIN was ground off and this one is the replacement.

Do you have paperwork to go with it?  What number is on the motor?

[Timboslice]

No it's just the frame, my old man has been accumulating and building h4's for years and I nabbed this frame out of his shed, he's no longer with us to ask about this particular frame, I understand that there's some variations over the years with the frames and I'm trying to make sure I buy the right parts. I'm tempted to start again with a different frame although I've put in a bit of work with this one. Maybe a head stem measurement where the bearings are housed might at least put me In the ball park, apparently that is difference between year models?

[754]

Rear peg mounts and sidestand can help id frame year, is there a seat latch or lock ?

[atm cycles]

What 754 said. Post more pictures

[ekpent]

 Post a picture maybe of the seat hinge bracket on the frame.

[Timboslice]

Does this help? i compared it with a 72 and looks very similar

[754]

I think 72 -76.. Looks like.

[Timboslice]

Cheers for the help!

[Don R]

 It may be a Factory replacement frame, I have one frame and two blank engines.
 I bought a 750 with one from my brother, he got it from a guy we knew for decades. I thought I lost the title and was going to write down the vin numbers for the lost title. No tag and blank. To make matters worse it's a 71/72 hybrid. Early forks, late gauges, light console, high 71 engine number. Late taillight and fender. No tag, so no build date. Mine has no rivet holes for the tag either.
 I read they made running changes going into the 72 model, as in bikes with early gauges AND a light console.

 No paperwork?

[754]

 Not sure about 71, I think 72 is first year for the helmet brackets on the rear brace.

[Don R]

Correct Frank. 72

[Don R]

 I wonder, since the 71 and 72 seat latches are different if the frame bolt holes are changed? Doesn't apply here, just hijacking for a second.

 I've got most years in the shop right now since I bought the collection, I could check differences if we can come up with things to compare. No swingarm so that won't help.  Is there another difference between the 72-76 years? I'm thinking no. When does the seat flip sides?
 
 

[Stev-o]

Not sure about 71, I think 72 is first year for the helmet brackets on the rear brace.

Did you notice the hinges are on the same side as the helmet hook?

[atm cycles]

My early k2 is the earliest bike I have with helmet holders. There's one on each side.