Removing block / Polish piston tops?

Two quick questions:

Yesterday I took off the head from my KZ1000P, and the cylinder block lifted a couple of centimeters as well (I just know that if I had wanted to remove the cylinder block, it would have been stuck for sure). I can push it back, but I'm not sure the gasket would still seal. It seems to be undamaged, but then again... I've got a gasket set, its just that I understand getting the block installed over the piston rings is not easy nor fun to do. Should I lift it completely and replace the gasket? It would make cleaning the carbon off of the piston tops and the top 5mm of the cylinder walls a bit easier (less chance of bits of carbon dropping in the engine). Any tips on how best to get the block back in place?

The second question is on the piston tops: there is a moderate amount of carbon on there, and it is really lose, it comes off when scratching with a fingernail. Is that normal? On the head and valves it is pretty though stuff to remove. The piston tops aren't all that smooth, and I was thinking of polishing them to reduce the buildup of carbon. Is that a good idea?

my 2 cents, the gasket is prob gonna leak, so to be safe replace it.
while you have the head off might as well replace the seals, you prob are seeing the result of oil on top of the pistons.
polishing them is not really going to do anything they will still get a build up on them no matter how shiney you make them

BSKZ650 wrote:

my 2 cents, the gasket is prob gonna leak, so to be safe replace it.
while you have the head off might as well replace the seals, you prob are seeing the result of oil on top of the pistons.
polishing them is not really going to do anything they will still get a build up on them no matter how shiney you make them

Okay, I'll pull the jugs and replace the gasket. As for the pistons, I'll just clean them up.
I am going to disassemble the head, clean the valves and combustion chambers, lap the the valves/seats and replace the oil seals. You're right that the carbon is probably the result from oil-seal leaks, as the carbon deposits are easy to remove and just a little bit oily. The cylinder walls show no scoring, in fact, I see what seems to be a honing-pattern.
Any tips on getting the jugs back on?

Personally, I would never have peace of mind if I didn't replace the gasket. But, if it is undamaged and you want to reseal it, you could raise the cylinder a bit and run a thin bead of sealer around it like 3 Bond or Permatex Ultra Black or similar.

Polishing the tops of the pistons doesn't do a whole lot, but I did it when I put the new ones in mine. You are not supposed to do it with the cylinder on because the carbon falls down and gets in the ring grooves.

JC Whitney sells cheap ring compressors, that's what I used. Some people use big hose clamps. Just be careful, the oil rings are easy to break.

I'm not big on saving gaskets either..........BUT I will admit to having done it more than once. I've never had a leak when I've sprayed the gasket with a couple thin coats of copper gasket spray and I've even used it on headgaskets of watercooled motors that I've roadraced.

mjg15 wrote:

I'm not big on saving gaskets either..........BUT I will admit to having done it more than once. I've never had a leak when I've sprayed the gasket with a couple thin coats of copper gasket spray and I've even used it on headgaskets of watercooled motors that I've roadraced.

It is not so much that I want to reuse the gasket, more that I started with just a cylinder head refurbishment and no I'll have to pull the jugs as well. It is starting to look like I'll have to do a further stripdown though, as I found a few metal slivers and some fine metal particles on the magnetic end of the oil drain plug. The bike has been standing for three years, and when it was put away (with a carb holder bolt broken off in the head) it had been jumping out of second gear into neutral a few times. I was hoping this was due to the easily reachable spring or selectors at the side of the engine, but now it seems it might be the shift forks.
I'll be dropping the oil pan tonight, and hopefully I'll know more then. And so it starts, one thing leading to another: top-end refurbishment -> complete engine rebuild -> might as well get the frame powdercoated -> why not a new paintjob...
Right when I'm rebuilding the Z1000A as well.