re the engine I just had apart and put back together ... long story, but I've got time, so why not.
Engine in question is that of a 2004 Kawasaki ZX10R which I've owned since new.
I had it apart originally with about 70,000 km on it. At that time, it was running well, but it had become apparent that this specific engine in that specific year had a "ticking time bomb" inside it because a set of thrust washers in the alternator (which is internal, in this engine - not like cars) were not properly heat treated. There was a kit available to replace them with washers with different heat treatment ... but no recall, because the original washers generally lasted long enough to get through warranty. The kit was "race kit" parts. The issue was quietly fixed for the 2005 model year.
While there was a theoretically possibility of doing this in-frame, I opted to go through the whole engine and fix a couple of other known weaknesses - like the valve retainers, which I replaced with those from the 2008-2010 model, which are stronger. (the '04 - '07 retainers are known to crack from time to time) And might as well do some upgrades of course while we are in there ...
And that brought up the question of what to do with the cylinder walls, which are plated aluminum. I know what to do with cast-iron cylinder walls but opinions of what to do with plated aluminum cylinders ran the gamut from "nothing", to "clean them up with red Scotchbrite and call it good", to "just glaze-break them as normal", to "glaze-break them but you have to use a special tool made of X", to "no honing tool short of diamond will touch them", to "you have to send it out to this specialty company that reworks them" (at significant cost and lead time). Of course, everyone who has an opinion on this matter says that everyone else is wrong, and there's no way to tell from my end of the internet who's speaking the truth and who's spouting words that they read somewhere.
At that time (70,000 km) I opted to do what the factory service manual said ... Nothing. Put in new rings and go. I figured that if I didn't do anything but should have, I could always go back in there and do it again, whereas if I did something but shouldn't have, there was no going back.
Well, as it turned out (and not that I was terribly surprised), that was a mistake. The cylinder walls were too smooth for proper ring break-in. It burned oil from the get-go. It ran OK but never really made the power that it should have for what else was in there (Wossner high-compression pistons, select-fit head gasket for proper squish clearance, degreed cams, etc).
I've since put another 25,000 km on it, adding about a litre of oil every 1000 km the whole time.
So this winter's project to keep me busy, was to pull it apart and go through it again. Of course, the same question comes up ... what to do with the cylinder walls.
I know what proper cylinder wall finish looks like and feels like on an engine with cast-iron liners and I have the tool to do it. So, given that I now knew that I had to do "something", I started with what I figured would be the least-aggressive things to do among all the things that the internet suggests to do, and work up until I found something that worked.
In order ...
Scotchbrite did absolutely nothing except wipe off the slight bit of carbon built up above the top travel limit of the upper compression ring.
Emery cloth wrapped around the arms of a normal 3-arm glaze-breaker did nothing.
Aluminum-oxide 240 grit sandpaper wrapped around the arms of a normal 3-arm glaze breaker seemed to do a little bit but not something that I was happy with.
The normal 3-ring glaze breaker, as is without any other nonsense, well lubricated and turned with my fingers only just to see if it would touch the surface ... did something. So I chucked it up in the drill and gave it a quick de-glaze following the normal process as for cast-iron liners except only for a couple of seconds because you do NOT want to wear through the coating.
The cylinder walls look OK. They are visibly scratched up in a roughly 30 degree crosshatch pattern. No hand tool will achieve the uniformity of how the factory does it on their machine. But it's crosshatched now.
I've had the engine running and it seems OK. Weather (winter) precludes any sort of test-ride. I plan on not starting the engine again until such time as I can beat on it a little to encourage the piston rings to seat within the first 50 km or so. That could still be a couple of months away.
Even if this doesn't achieve "perfection" ... even if it still uses oil but only half as much ... I'll be happy with that.