Topic: A Difference Between the CB750A and the Other SOHC4 750s

[bill440cars]

       I was just doing some reading into the info on the 750A and discovered that you can disassemble the top end of the 750A, w/o pulling the engine from the frame. I figure that the 750A frame is somewhat different because of it being an automatic, but had no idea that the upper part of the frame was different from the others. Curious why Honda didn't use the same frame design (in that area) on the other 750s. Of course, by the time the 750A was made, there wasn't much time left on the run of the SOHC 750s anyway, maybe that's why. Anybody?

[DarkRider]

They were probably using a prototype of the DOHC frame with the 750A

[bill440cars]

They were probably using a prototype of the DOHC frame with the 750A

           The DOHC frame has a removable lower right frame rail. There's not much telling. Folks that ordered and installed (or had installed) Gordon's (Ilbikes) frame kits were the the only ones I've known of that you could pull the top end of a 750 SOHC w/o pulling the engine from the frame, until now. Of course, if Honda would have redesigned the other 750 frames, they might have had to make other changes too and maybe that's why.   

[rbmgf7]

i often wondered the same reason why honda didn't use this frame on all their models everytime i install/remove engines. i have a spare 750A frame i intend on using on my next project as it should make installation a sinch. as far as i know, the frame is similar to the other frames but with the raised support tubes and a little funkier kick stand mount.

i was fortunate to receive the stock 4-2 exhaust system. anyone know anything about these exhausts? seems restrictive with the 4-2 joint tubing being the same diameter as the leads out from the cylinders. my idea was to get ahold of some norton peashooters and use those in place of the hondamatic muffs.

[bill440cars]

        I can't really help you on that, I'm still learning about these bikes myself. Got a 77' model myself and hoping to pick up any unfo I can, on it.

[tramp]

someone was thinking when they designed that one

[eldar]

Weight. Pure and simple. The auto engine weighs more cause of the transmission.
Think about it. If you can pull the valve cover off, you can pull the head and the jugs, while leaving the engine in. As the auto, from what I understand was virtually indestructible, why pull the whole engine. though it would have made sense to do that with the later years as well. After all, the tanks are the same, unless the bottom is formed different.