Topic: 1977 750k frame differences??

[mono]

So... I have these 2 frames, both tagged as 1977 on the plate, with stamped VINs that match the plate and no signs of being chopped.  Yet the seat/tail sections are significantly different....

Pardon the bad pics.  Noticed it when I was home for lunch.  Opinions?

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[mono]

The frame with the tank on it is about 4" shorter, and the seat hinges are on a different side.  I'm stumped.

Passenger peg triangles are even different.

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[mono]

Did something happen to Lucky?? I know he can answer this lol....

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[750K]

Seeing as I have both a 77k for a daily rider and a 78k parts bike I can say that the seat lock is on the right side and the seat hinges are on the left. That is if you were sitting on the bike, maybe the second one is an F? Just a guess seeing as the last time I saw a 77-78f model up close was a couple years ago.

[mono]

I was thinking one may be an F, but they are both stamped K... Not sure how that worked.


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[mono]

Hmm.  Just scoped out TimT's 750F build thread and his frame looks a lot like my bare frame... 

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[ekpent]

Maybe of you look up some model specific seats on E-bay you can see what hinge setup the different models used as a quickie clue.

[mono]

Good suggestion!   Looks like the SS had the hinges on the left.
http://www.cmsnl.com/honda-cb750f-750-super-sport-1977-usa_model491/partslist/F++15.html

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[mono]

This $50 roller keeps getting better and better lol....

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[754]

 F Model the sidestand is in different location..further back.

[mono]

Hmm.   This is perplexing!   

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[750K]

Are you sure it's a 750?

After looking at pics of a 72 cb750 I have waiting in the wings I bet you have an earlier pre 77-78 frame, the seat hinges are on the opposite side of the 77-78's. If its titled as a 77 someone might have switched the vin plate from a late model bike. Check if the stamped vin on the neck tube matches. Check the rivets on the vin plates of both frames to see if they're the same kind? Give the vin#'s and I'm sure someone here can id them as well.

[mono]

As I said earlier, the neck stamps match the vin plate.  That said, I suppose a good welder could have chopped it but I can't tell.  I'll take better pics later cause this is turning into a fun  mystery!    Haha. 

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[754]

 It may be last of the old frames coming down assembly line after new style was introduced. Could be one line ran out of frames, so they pulled one out of parts inventory and numbered it in the current sequence..

[mono]

It may be last of the old frames coming down assembly line after new style was introduced. Could be one line ran out of frames, so they pulled one out of parts inventory and numbered it in the current sequence..

yeah, people have mentioned before that this happened from time to time - i figured that this may be the case.  I'd still like to know for sure though, because the differences in the frames is pretty significant --- to the point that if i had blindly ordered an aftermarket seat, it would not work!

[750K]

Huh, yeah that's is puzzling indeed, I wonder what the real story behind it is. Too bad these old bikes can't talk, haha.

[mono]

Well, just got done pulling the Lesters (confirmed) off this roller.   Flipped the frame over and I found out what's up: the frame has been chopped.  There are (seemingly well done) welds where someone patched the head to another frame.

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