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[vagabond6542]

AJ,
I have a question, is the Jester completely stock?
The crud looks as if that the cylinder had been run rich and the mixture been settling around the intake valve.

Chief,
You and I talked about head configuration just recently, you could see what I was talking about.

Just my .02 observation. 

[Chief]

AJ,
I have a question, is the Jester completely stock?
The crud looks as if that the cylinder had been run rich and the mixture been settling around the intake valve.

Chief,
You and I talked about head configuration just recently, you could see what I was talking about.

Just my .02 observation. 

AJ is running a PClll on the bike. It might have even been a map I sent to him. The pictures do indicate that the rear was running richer than the front. The exhaust valves show that pretty clearly. Richer means cooler, so I guess the temps oculd have been worse than they actually were.

[sadunbar]

AJ is running a PClll on the bike. It might have even been a map I sent to him. The pictures do indicate that the rear was running richer than the front. The exhaust valves show that pretty clearly. Richer means cooler, so I guess the temps oculd have been worse than they actually were.

I am not so sure you can detect lean vs. rich in the pictures AJ posted.  Pretty good bet you are seeing the effects of burning oil, not excess gas.

[Chief]

I am not so sure you can detect lean vs. rich in the pictures AJ posted.  Pretty good bet you are seeing the effects of burning oil, not excess gas.

I don't buy the burning oil argument. I don't understand how a gasket can let low pressure oil in while not letting high pressure combustion gases out. Now, if the valve guide seals are bad, that's a different story, but I don't think oil is getting in at the head gasket.

[sadunbar]

I don't buy the burning oil argument. I don't understand how a gasket can let low pressure oil in while not letting high pressure combustion gases out. Now, if the valve guide seals are bad, that's a different story, but I don't think oil is getting in at the head gasket.

Chief,

Look at the picture in reply 13 - especially around the spark plug.  JMO, but that doesn't look much like carbon from rich to me...

Scott

[Hoist!]

The oil will leak outside past the gasket on the upstroke, and gets sucked in on the downstroke. So you would be burning any oil that got sucked in on the next power stroke.

Hoist!

[vagabond6542]

Chief,

Look at the picture in reply 13 - especially around the spark plug.  JMO, but that doesn't look much like carbon from rich to me...
Scott

Sad,

You are correct about the chamber carbon, which encompasses the entire chamber. that came from the engine trying to burn off the oil that was getting into the engine on the intake stroke. Remember, we are running a aspirating engine.  
The problem of gasket failure caused the carbon build up.

Geo

[Chief]

Chief,

Look at the picture in reply 13 - especially around the spark plug.  JMO, but that doesn't look much like carbon from rich to me...

Scott

I know what you're saying, I just don't think oil can be getting in if combustion air isn't getting out.

[Chief]

The oil will leak outside past the gasket on the upstroke, and gets sucked in on the downstroke. So you would be burning any oil that got sucked in on the next power stroke.

Hoist!

I'm sorry. I just don't buy it. Total vaccum is only 14.7 psi differential. These motors crank with 150 psi without combustion. How much pressure is created under combustion? I can't accept that oil, which is thicker than air, is being sucked in with less than 15 psi of pressure differential while high pressure combustion gases are not getting forced out through the same hole. That theory just doesn't hold water.

Sorry, but I'm just not a buyer of that one. Physics says it won't work.

We get piston blow-by, not suck-in. If it's oil, it needs to be coming from somewhere else besides past the gasket.

[sadunbar]

Choices are valve guides, piston rings, head gaskets or thru the intake....

[Chief]

Choices are valve guides, piston rings, head gaskets or thru the intake....

At least we know it's not a cracked block.

[vagabond6542]

I'm sorry. I just don't buy it. Total vaccum is only 14.7 psi differential. These motors crank with 150 psi without combustion. How much pressure is created under combustion? I can't accept that oil, which is thicker than air, is being sucked in with less than 15 psi of pressure differential while high pressure combustion gases are not getting forced out through the same hole. That theory just doesn't hold water.

Sorry, but I'm just not a buyer of that one. Physics says it won't work.

We get piston blow-by, not suck-in. If it's oil, it needs to be coming from somewhere else besides past the gasket.

Chief,

I came out the Semi-conductor field some twenty years ago. I dealt with Plasma Etchers that had vacuum in the Milli-torr range.
The thought of oil getting into the cylinder on the intake stroke and high compression going out the same way would not be farfetched. Remember, there is a gasket design problem along with a couple of possible  unknowns.  
I know, I've seen vacuum pull teflon oil out of a roughing pump when a chamber was left under vacuum when shut down.

Just my .02.  

[vagabond6542]

Chief,

I came out the Semi-conductor field some twenty years ago. I dealt with Plasma Etchers that had vacuum in the Milli-torr range.
The thought of oil getting into the cylinder on the intake stroke and high compression not going out the same way would not be farfetched. Remember, there is a gasket design problem along with a couple of possible  unknowns.  
I know, I've seen vacuum pull teflon oil out of a roughing pump when a chamber was left under vacuum when shut down.

Just my .02.  

Sorry hit the wrong key. Oops

[Chief]

Chief,

I came out the Semi-conductor field some twenty years ago. I dealt with Plasma Etchers that had vacuum in the Milli-torr range.
The thought of oil getting into the cylinder on the intake stroke and high compression going out the same way would not be farfetched. Remember, there is a gasket design problem along with a couple of possible  unknowns.  
I know, I've seen vacuum pull teflon oil out of a roughing pump when a chamber was left under vacuum when shut down.

Just my .02.  

All of the gasket problems have been related to keeping the non-pressurized oil draining out of the head going in the right direction. I haven't seen any gaskets that were burned up, or any that have shown any signs of blow-by at the fire ring. The tops of the sleeves have all looked fine, all the way around. The seal looks intact, so does the sealing surface of the heads. I don't think oil is getting in past the fire ring. The evidence just isn't there.

All of this burning oil talk is because the pictures of carbon deposits in the combustion chamber. I haven't heard anyone complain of high oil consumption or complaining of blue smoke out the tail pipe or plug fouling or other normal symptoms of burning oil.

Maybe instead of burning oil we're dealing with a poorly designed combustion chamber that isn't efficiently burning the fuel which is leading to some extra carbon build up? I'm more inclined to put my money on that one, at least until I see evidence otherwise.

[sadunbar]

Chief,

  AJ's pictures look far worse then my motor when it came apart.  My front cylinder, piston and head looked like a normal properly running engine should.  Nice tan color on the piston, head chamber and spark plug.   My rear cylinder had heavy carbon build up on the cylinder fire ring, piston, spark plug and head.  My rear piston rings were shot - my front piston rings were normal.  As bad as my rear cylinder components looked, they were nothing as compared to AJ's.  I am not suggesting where the oil came from in AJ's pictures, but IMO, AJ's components show more then carbon buildup.  Maybe his valve guides are shot from 19K of spring retainers hitting the rocker boxes?  Or maybe his rings are shot?  But his pictures indicate more then carbon buildup from a poorly designed combustion chamber, ect.  IMO, oil is finding its way into the combustion chamber from somewhere...

Scott