KZ1100 Pistons carbon removal.

Hi all , please can someone help me, I have a 1981 kz1100 A1 Shafty.

I had to remove my barrel due to oil leak from base gasket. When taking the barrel off i noticed that my piston heads were very built up with carbon. Now my question how much carbon should be on the top of the piston.

My spark plugs are very black and sooty, not wet dry....no 3 spark plug was the only one that was correct burning light brownish...but no 3 piston had the most carbon on.Is this correct.
Aslo what is the best way to clean the pistons of csrbon.

Thank you very much.
Travis
South Africa.

since you have the bike down, have you checked the cyls for size to make sure they are still in spec?
at this point assuming they are still in spec I would hine the cyls and replace the rings and valve seals. as far as cleaning the carbon, carb cleaner and a wire brush works well, just make sure to stay away from the ring lands, exept for carb cleaner to remove carbon from them

Acetone (non chlorinated brake cleaner spray) and a toothbrush. Scotchbrite pad for the stubborn stuff.

3 or 4 hours in full strength Simple Green. However, the more carbon on the top of the piston, the higher the compression ratio. Remove the carbon, loose a little power.

If you were running in a race class that had a spec piston, it never said how much carbon you were allowed, but the racers never removed it.

APE Jay wrote:

3 or 4 hours in full strength Simple Green. However, the more carbon on the top of the piston, the higher the compression ratio. Remove the carbon, loose a little power.

If you were running in a race class that had a spec piston, it never said how much carbon you were allowed, but the racers never removed it.

I whole heartedly agree!

There was no spec for head/base gasket thickness back when too...

most of those bikes that had enough carbon buildup on them to increase performance did not last long (according to Evil Jimmy)my 4 stroke mentor LOL

And we used to bake on three coats of VHT to the piston tops.
It built up a great layer of carbon evenly on all the pistons. FAST !

Hay, the rulebook didn't say we couldn't.
It just came down to keep your mouth shut and let the machine speak.