Topic: Removable engine mount

[Laids]

I was looking at a K7 frame I just got, the engine was out but a case guard on the left side was still on. I noticed the engine mount was removable. It appears to be factory, anyone know the story behind this?

[beemerbum]

That's just the nature of the '77 and '78 CB750 K frame. For some reason, Honda chose to make some significant changes to a motorcycle that would change totally in '79. Does anyone know the corporate history for this time period?

[Laids]

I also have a 78 and it has a traditional frame mount same as all other years. As well I have seen other K7s that do not have a removable mount. 

[754]

Some of them also have the engine serial number in line with the wheels.. ie turned 90 degrees,

[beemerbum]

It would be very interesting to hear from our resident expert Hondaman as to why all these differences in '77 and '78 frames.

[jlh3rd]

I believe this came up a while back in a discussion, and it appears the 77 only has this , yet that part is not on the fiche. It still shows the welded boss.
Yet you can barely make out the part on the honda guide pic.

[onepieceatatime]

I believe this came up a while back in a discussion, and it appears the 77 only has this , yet that part is not on the fiche. It still shows the welded boss.
Yet you can barely make out the part on the honda guide pic.

Here is that discussion:
http://forums.sohc4.net/index.php/topic,176458.0.html

[beemerbum]

Thanks for posting. Learn something on this site every. Still wondering why Honda did that apparently for '77 only.

[BenelliSEI]

This is definitely an “unsolved mystery”. From my investigation, it’s only on K7’s and I’ve seen some late ones with a standard lug! It’s a very well made part and my K7 is the easiest frame to pull or install the engine. I’ve never seen a definitive explanation.

[754]

Well they had 2 assembly lines far as I know, and they must have been prepping for the switch, coming soon to the DOHC..

[Laids]

I believe this came up a while back in a discussion, and it appears the 77 only has this , yet that part is not on the fiche. It still shows the welded boss.
Yet you can barely make out the part on the honda guide pic.

Here is that discussion:
http://forums.sohc4.net/index.php/topic,176458.0.html

My theory is that the Honda engineer for the frames on the K7 was responsible for the removable mount and getting rid of the weep hole on the frame. He was then fired for 78, the removable mount was removed and the weep hole returned.
Just a theory

[beemerbum]

Having made such a grievous engineering error, he brought dishonor upon himself and his family. Accordingly, he committed seppuku. Just a theory.