Alright, let’s talk about this old beast, the 1980 Honda CB750K I’ve been messing with. Got my hands on it a while back, wasn’t exactly pretty, but the bones seemed okay. Looked like it sat for a good long time, you know? Covered in dust, tires flat, the usual story for a bike this age.
Getting Started
First thing, had to give it a good wash down. Just layers of grime everywhere. Once it was cleaner, I could actually see what I was dealing with. Checked the frame for any major rust or cracks – looked solid enough, thankfully. Then, pulled the plugs, took a peek inside the cylinders with a cheap scope. Looked okay, no obvious horror show.
Next up was figuring out if the engine would even turn over by hand. Put a wrench on the crank nut, gave it a gentle turn… success! It wasn’t seized. That was a huge relief, honestly. Didn’t want to dive into a full engine rebuild right off the bat.
The Fun Part – Taking Things Apart
So, I started taking stuff off. The tank came off, seat followed. This exposed all the wiring and the top of the engine. Man, the wiring looked like spaghetti someone threw against the wall. Lots of brittle connectors and questionable old tape jobs. I knew that was going to be a headache later.
The carburetors were definitely next on the list. Pulled the whole rack off. Taking them apart was… interesting. Lots of gummy old fuel and varnish inside. Every single jet was clogged solid. Spent ages cleaning those things. Soaked ’em, scrubbed ’em, blew compressed air through every passage I could find. Had to order rebuild kits, of course. New gaskets, o-rings, float needles – the works.
- Cleaned carbs meticulously.
- Replaced all the little rubber bits.
- Bench synced them as best I could.
Engine and Electrics
While the carbs were off, I checked the valve clearances. A few were a bit tight, so I adjusted those. Changed the oil and filter too, obviously. The old oil was nasty black sludge. Put in some fresh stuff.
Then tackled some of that wiring mess. Didn’t rewire the whole bike, just fixed the really bad spots. Replaced some connectors, cleaned grounds, chased down a few obvious breaks. Put in a new battery too, the old one was toast.
Brakes and Tires
Brakes were non-negotiable. Pulled the calipers apart, cleaned the pistons. They were sticky. Replaced the seals, bled the system with fresh fluid. The master cylinders got the same treatment. New pads went on too. Safety first, right? Tires were cracked and hard as rocks, so got some new rubber mounted up.
Putting It Back Together & First Try
Started reassembling. Put the cleaned carbs back on, hooked up the fuel lines (replaced those too, they were brittle). Put the tank and seat back on. Double-checked connections. Filled it with fresh gas.
Okay, moment of truth. Turned the key, lights came on. Hit the starter… it cranked! Coughed a bit, sputtered. Gave it a little choke, tried again. Vroom! It actually fired up! Ran rough as heck, but it was alive. Let it warm up a bit, then tried syncing the carbs properly with vacuum gauges. Took some fiddling, but got it idling much smoother.
Current Status
So yeah, it runs now. Took it for a short spin around the block. Still needs fine-tuning, probably rejetting the carbs a bit. The suspension feels kinda mushy, might look into that next. And the paint is rough, but hey, it’s a rider for now. It was a process, lots of skinned knuckles and head-scratching, but getting that old engine breathing again felt pretty darn good. Still more to do, always is with these old bikes, but that’s the journey, I guess.
