Top-end apart. Severe carbon build-up normal?

I'm trying to keep my project thread up to date with pics and didn't think I should double post them here, so apologies for the redirect.

I'd appreciate hearing what you guys think of the pictures of the cylinders and head I just posted on my project thread (Link in my sig below).

Is this amount of carbon build up normal? This is my first engine rebuild so I'm not sure what to expect. The engine is out of a KZP w/ 39k miles on it, and it was stored for 15 years before being resurrected a couple years ago. Less than a 1000 miles on it since then and before engine tear down. I don't have the exact figures at hand, but the compression numbers varied widely with and without oil.

Any and all input appreciated!

ive seen a whole lot worse.ist order of business is to get it all apart and clean everything and start measuring parts for wear

Hey DudeLee,

Cross posting is agin the ruels, but you deserve credit as that's the most elegant cross post I've ever seen.

Good on Ya!

KZCSI

The engine is out of a KZP w/ 39k miles on it,

The key word is KZP, as in "Police Bike", and I would expect to see that in a cop bike.

Not good, but not terrible either.

LeeLewis7 wrote:

I'd appreciate hearing what you guys think of the pictures of the cylinders and head I just posted on my project thread (Link in my sig below).

Is this amount of carbon build up normal?

I've seen a lot worse.... when I pulled the head off my 750. That piston with the extra crud on top might be hardened oil leaking down from a valve guide (that's what it was on mine).

BTW: if you are not going to pull the cylinder, it's really tempting to try to scrape the crud off the top of the pistons with them at TDC.... and the FSM specifically warns NOT to do it because hard carbon will get down the sides and scuff the cylinder walls.

Of course.....if somebody was to tightly pack tissue around the edge of the piston gap, scrape carefully and vacuum the crud OFF the top...



LeeLewis7 wrote:

The engine is out of a KZP w/ 39k miles on it, and it was stored for 15 years before being resurrected a couple years ago. Less than a 1000 miles on it since then and before engine tear down. I don't have the exact figures at hand, but the compression numbers varied widely with and without oil.
Any and all input appreciated!

That generally means the rings are hosed.

Okay, could be better, could be worse. That's good news. Some carbon was expected, but I wasn't prepared for this. I'd run several tanks of gas w/ Seafoam, but I guess even that couldn't overcome 39k hard miles.

I've already psyched myself up to take the cylinder block off, so cleaning the pistons properly once apart won't be a problem. Seems like I read somewhere that acetone is good to cut carbon buildup.

LeeLewis7 wrote:

Okay, could be better, could be worse. That's good news. Some carbon was expected, but I wasn't prepared for this. I'd run several tanks of gas w/ Seafoam, but I guess even that couldn't overcome 39k hard miles.

I've already psyched myself up to take the cylinder block off, so cleaning the pistons properly once apart won't be a problem. Seems like I read somewhere that acetone is good to cut carbon buildup.

It's good for loose carbon, greasy dirt or general crud. But, the flame-broiled burned on stuff won't budge. I have probably cleaned pistol barrels ten thousand times muttering about how I wish there was a cleaner that would actually dissolve hard burned on carbon (without dissolving the metal it's on).

I have heard many claim it, tried them all, and found none that actually worked. The closest I found is the super hot berryman's dip tank cleaner, but you have to leave them in for a few weeks. It softens it but you still have to scrub.

A scotchbrite pad and elbow grease will shine up the pistons.

BTW: you won't believe how much hardened crud is in the piston grooves.

use a broken ring to clean the ring grooves.wrap the skirts and bottems of pistons with several layers of duct tape then just glas bead the tops if you have access to a cabinet