Ahoy! New Member Here...1982 GPZ550

Well I finally got around to rescuing this beauty from my brother, who has had it under a tarp next to his garage for the last 2 years. He bought it about 3 years ago in southern CA. The previous owner had K&N pod filters on it...unknown if it was ever re-jetted. My brother didn't ride it long before blowing a hole in one of the pistons. He tore it apart, saw the hole, and said F it. It's been sitting ever since. He is convinced it's just a parts bike at this point. I'm setting out to prove him wrong. Challenge accepted!

I'll be lurking the technical forums, and probably asking many newbie questions haha. I'll be taking pics along the way, and will probably post a build thread at some point. Right now, my main focus is just getting it running. My initial thoughts are...clean out the crankcase, 615cc big bore kit, carb rebuild, and proper jetting. At just under 10,000 miles, I'm hoping it won't need much more than that to get running again.

Please feel free to chime in if there's anything i'm overlooking.

Good luck with your project!

Looks like the pods caused the mixture to be too lean and detonation holed the piston. If the bores still look good I'd just get some good used/new stock pistons and rings. By the time you buy a big bore kit and get the cylinder bored you are going to be into the bike for an extra $600.

Hopefully the lower end didn't get water in it.
Steve

That was my brother's take on it too. Lean running seems to make the most sense. It may have had an exhaust leak as well. And he was riding it in SoCal traffic in the summer heat when it blew. I think it might be easier to find a stock airbox rather than trying to re-jet, and find the proper air fuel mixture.

The cylinders actually look very clean...i don't see any scoring at all. I might very well just buy some stock size oem pistons, rings, etc, and be done with it. Good call...i'm probably getting ahead of myself with the big bore kit.

Any advice on cleaning out the crankcase? I dropped the oil pan today...the filter looked fairly clean. I didn't really sift through the oil, but i didn't see any big chunks of metal or anything. I'm actually really surprised how clean everything looks on the inside. Anyway, I was hoping to avoid pulling the whole crankcase out....is there a good way to clean it without removing?

I flush with diesel.
Steve

If the sump looks clean you are done. Put the pan back on with a new OEM Kawasaki gasket and call it done. The problem with using solvents to flush the sump is that you will have residual solvent in the system even after changing the oil. Throw some Shell Rotella 15W-40 oil in the engine and change it out at 1500 miles if you want to do further cleaning, but I doubt it's need.