Honda-SOHC

SOHC.co.uk Forums => CB750 => Topic started by: Grewth on August 11, 2025, 02:25:42 PM

Title: A bit of a conundrum ? CB750K1 ?
Post by: Grewth on August 11, 2025, 02:25:42 PM
I've gone done it again.
Bought a pig in a poke by the looks of it.
Allegedly the frame for a '71 CB750K1, but with a few interesting modifications.
If anyone can be bothered,  I'd like to know exactly what isn't standard on this frame, I think I've already spotted six things that need to be altered in order to put this frame back to standard condition.
I'm wondering if I've missed anything  ?
Title: Re: A bit of a conundrum ? CB750K1 ?
Post by: Grewth on August 11, 2025, 02:27:23 PM
More
Title: Re: A bit of a conundrum ? CB750K1 ?
Post by: Nurse Julie on August 11, 2025, 05:15:10 PM
Yes, that VIN relates to a K1 frame. Paul Gledhill restored a UK K1, if you find the thread before I do, there may be some photos of his frame.
Title: Re: A bit of a conundrum ? CB750K1 ?
Post by: Grewth on August 11, 2025, 06:43:40 PM
Yes, that VIN relates to a K1 frame. Paul Gledhill restored a UK K1, if you find the thread before I do, there may be some photos of his frame.

Thank you Julie !
Nice to hear it is actually a K1 after all.
Well at least the frame numbers are original Honda,  and unmolested,  unlike the rest of the frame.
I've been busy with my grinder since I made the original post.
All the nasty added on bits are gone now, that's the easy bit
done.
Now I've got to fabricate new rear subframes for the pillion footrests, add a side stand bracket  (got one I cut off a K7 frame)and finally add a horn bracket.
Luckily I've got a K5 frame to copy from, or I really would be struggling [attachimg=1]
Title: Re: A bit of a conundrum ? CB750K1 ?
Post by: Bryanj on August 11, 2025, 08:19:22 PM
Personaly i would remove the "patches" and do a better job
Title: Re: A bit of a conundrum ? CB750K1 ?
Post by: Grewth on August 11, 2025, 09:11:45 PM
Personaly i would remove the "patches" and do a better job
That's not a "patch" it's the original saddle plate that the side stand mount was welded to.
Whoever cut the mount off did a wonderful job of removing any grinding marks, it's dead smooth.
Title: Re: A bit of a conundrum ? CB750K1 ?
Post by: archmill on August 12, 2025, 08:29:23 PM
Grewth, fancy a frame kit ?
Means you can install the engine in big lumps (bottom end / barrels / head / top end) or install the engine built up a lot easier.
(http://)
Title: Re: A bit of a conundrum ? CB750K1 ?
Post by: Grewth on August 12, 2025, 10:20:44 PM
I think that my poor old frame has been mutilated enough already,  without hacking the top rails to bits.
If you build a 750 four motor properly in the first place, it shouldn't need pulling down again for 50,000 miles or so.
Even the F1 motor I threw together from three tea chests of bits was still running strong 20,000 miles later