Hello everyone,
As i am new to this forum i want to start by introducing myself: I am a 30 year old living in Holland and i've spent the last 8 months restoring a 1977 CB750 K7 back to factory original condition.
This is my first motorcycle and my first restoration, though i do have some experience working on cars. Before you start reading, i want to say how awesome it is to have the sohc4.net forum as a resource when working on a bike like this, it has helped me immensly to be able to access this immense amount of knowledge when i couldnt work something out.
I also want to say that this topic does not fully cover all aspects of the restoration or describe everything that i have done, so you will see that a few things may not be covered (such as rebuilding the brake calliper, the head light, rear wheel etc). This is simply due to the fact that i never intended to fully document the restoration. I just took some pictures here and there, but also frequently forgot to take pictures. And i only decided to create this topic afterwards when i saw how much material i had. Anyway, here we go and i hope you enjoy
PreviewAs the restoration is already pretty much finished i can show some befores and afters
Before:
After:
Build logI bought the bike in july 2018 from an online ad. I had zero knowledge of motorcycles at that moment, not to mention any knowledge of CB750's. Therefore i had no idea if the bike was anywhere near complete (hint: It wasnt) and how much time, effort and money it would cost to get it in decent shape. In hindsight i should have chosen a more complete bike to do a full restoration on.
Part 1 - The before's: As you can see the bike was in less-then-perfect condition when i bought it. Hell, it was pretty much held together by rust and external air pressure.
Shoutout to the brave and beautiful wifey who drove this roling junkyard home.
Part 2 - The teardown:After safely parking the bike in the garage that would be its home for the next 8 months, i started tearing down the frame to reveal all the nasties. I have to say that this was the first moment i realised what i had gotten my hands on. This was going to be a big project.
Some may have already noticed the big CMS box in picture 4, i guess you can already guess what was inside
I realised i have no picture of the engine removal. The reason for this is that it took me and a friend about 4 hours to remove it from the frame, because the front left engine mounting bolt was completely corrosion-welded to the block and we had to drill it out entirely. So i had a little too much on my hands to take pictures.
Part 3 - Engine disassembly:After removing the engine from the frame, i made a small engine stand from a couple of 2-by-4's i had left lying around and started disassembling the engine.
The engine stand allowed me to also tilt the engine forward so i can access the oil pump:
Plenty of nastiness going on here:
Cam looks somewhat worn but turned out to be usable after measuring wear:
Looks like it may have burned some oil:
After splitting the cases i realised i was not the first one to get into this engine: The cases were split before and whoever re-assembled it had been a little bit trigger-happy with the liquid gasket. This #$%* was everywhere. Also, there was a considerable amount of metal shavings and a very large metal chunk. I have never been able to find out where it came from, even though i have inspected each and every engine part multiple times closely