Ignore 13RoadKing; either trolling or just doesn't know what he is talking about as has been exhibited in some of his other posts. Maybe joking but if so should indicate.

20% and 30%, assuming the test was done properly and the data correct, is way too much. I would be rebuilding the top end with anything over 10%.

 

Sorry to hear of your issue man,
Definite problem there. Either the bore is off or the rings were not seated properly. How many miles on this build? I think you're gonna have to take it back down and have the pistons and bore's checked..... Earlier you stated you had to pull timing out to quiet it down. Is it possible it was running to Lean for break in and the rings got scored? Too much heat... can you post a pic of the plugs..... I believe MattVA had a very similar issue......

 

Tore the top end off and ran it down to the porter so we could check it out. Cylinders were pretty clean from any scoring outside of normal wear and tear for a build with less than 200 miles on it. Mic'd the cylinders and it appears to be round and straight.

Piston showed no signs of knocking at all. Knocking wasn't audible either while riding or on the dyno. It was something the ion sensor was picking up.
It's possible that I just didn't get a great break in for the rings.

Grabbed a set of take offs and getting them rebored, new pistons and rings.

Add some pictures. Those were new plugs installed for the dyno.

 

Is that coolant on the piston?

Look at the valve relief, It's no longer an even radius.. Were the valves hitting the edge of the pocket? CP pistons and stock valves shouldn't hit. How much was milled off the heads..

As stated 20/30% leak is too much.. One plug don't look too hot.. I'd also made sure the valves are sealing. Could be leaking from more than one place.

 

I'm with Mr. Headflow on the possible valve to piston contact. Could be the photo but looks like the outside edge of the intake valve kissed the piston. Better mock everything up and check clearance when you put it back together.

 

Coolant spilled when I removed the heads.
Not stock valves, 1.9 and 1.57.

When I get it put back together and check squish, I'll check valve clearance as well.

I zoomed in on my picture, I think it's just the flash that distorted the relief pocket.

 

I'd still be suspicious of that cylinder as I'd assume the oily plug came out of that one..

Not sure about the valve relief as a 1.9 should clear no problem but I would check it.

Sounds like you are going the right direction with cylinders and pistons plus having the porter check the heads..

 

Here are the front and rear heads. No witness marks on the valves so clearance is good.

 

I think you are OK as far as clearance goes but there sure seems to be a lot of oil.. Can you see any leaking down the guides? That amount of oil and leads me to believe something was wrong it either the valve seals or rings. Maybe second rings in upside down?

 

The exhaust ports show lots of oil getting through there as well.
For some reason or another the rings didn't set and oil was coming up from the crankcase.
That could also be source of the initial knocking that brought me to where I'm at today. Oil mixed in with fuel and air will affect resistance that the ion sensor is looking for.

New cylinders came in today so I'm rebuilding. Hope to have it done tonight and hit the road tomorrow for the break in.

Pistons and cylinders were matched so I shouldn't have any ring set issues.