Hi Oly, I have a similar story as yours and a similar K1, mine is an
11/70 and 18000 s/n higher than yours. That’s 6000 CB750K1s per month! And that is a lot of motorcycles.
I rode mine for several years (5000miles?) after a 15 year park, before I pulled the engine last time in 2007
I have had my engine out a couple times: nuisance oil leaks at the point seal and pucks/head gasket drove the decision to pull the engine. Also replaced the internal chains, cam chain and primary chains, tensioners “while I’m in there”. Also hone and rings “while I’m in there” but end gaps were good. At 70000 miles there was some carbon in the exhaust ports but still at 100000 miles no smoke. At least, I don’t see any smoke in the mirror, and no smoke reports from following riders.
Torque/retorque the head gasket was good advice.
My clutch was slipping badly even though the fiber plates measured good. I roughed the surface of the old plates and got temporary improvement. Finally new (supple) fiber plates have done the trick and the clutch now grabs like it should. I still have my original lifter plate and always loosen/tighten the four bolts slowly and evenly. Maybe I should have a heavy lifter plate on hand for my heirs, or the next guy that goes in there.
I’m not an engine builder, I have just the experience of one CB, this one.
My bike still goes from zero to illegal mighty fast without performance mods, not VRod fast, not CBR gixxer or Ninja fast, not even Z1 fast, but fast enough for this guy.
You’re doing a nice job Oly. Make sure you keep your measurements for the future.
Kevin, thanks for your response. It's nice to find someone with a bike manufactured so close to mine. I hope you don't mind if I bounce some questions related to your work on the bike.
1). Did you do any measurements on the valve stem to valve guide clearances?
2). Does your head have intake valve guides with oil seals and exhaust valve guides w/out oil seals?
3). I'm at the point in the engine disassembly where I need to determine if I should split the case and inspect for any issues. How difficult was it to open and reassemble?
FYI, I purchased the bike from the original owner and to my knowledge the engine had never been opened up, so I was surprised to find that there were no O-rings installed on the base of each cylinder. I'm wondering if this possibly was what caused so much carbon build that I saw.
Oly 1-2-3
1) I didn’t take any measurements as you did, I did the liquid test and it passed. Also decarbonized, lapped valves, polished ports a bit, matched intake runners to ports.
2) Yes, seals on intake, no seals on exhaust.
3) Not too difficult to open the cases, a lot of bolts, a few through the top, most through the bottom case, and a bearing holder near the gear change mechanism. I only opened the cases to replace the points seal, cam chain, primary chains and tensioner.
-Remove top case bolts
-Remove transmission bearing holder
-Invert engine
-Remove bottom case bolts
-Remove bottom case
I don’t know about missing cylinder orings
