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Which piston wash looks lean the Mag with the large carbon spot?

Looks like removal is definitely next. What do you mean by smeared/ stuck ring? As for the gauge, I checked it on other motors and it has always read even. After saying that, I will go borrow my buddy's gauge to verify.

Interesting, I will check that out. How did you correct it?

I took 3 measurements from each piston and cylinder using a telescoping bore gauge and Starrett Micrometer.

I really hope it's that, but I keep getting the same readings even after running the motor.

You know that is exactly what I thought too, but I tested comp numerous times after riding.

According to the ADA cc chart 36cc domes should get me right around 175, and that's exactly where the MAG Cyl is at.

Domes have been swapped, and made no change. I installed a set of 37cc domes, and the problem persisted of the PTO Cyl reading 25psi higher. I measured the exhaust port heights from the deck, and got the same numbers on both cyls. After I picked up my cyls from the machine shop, I measured...

I adjusted the ring gaps, but they were pretty much spot on to spec from the box. I think that the glare from the WD on the walls is throwing the photos off. The final hone was to 320.

I would say at least 35mm which would be around 1 3/8"

I can make something to cc the domes, and I have access to 35cc and 37cc domes to help diagnose. I will install different sets, torque them down and see if it's still 25 psi off. Yeah, It's really weird that my problem is high comp. low comp would be so much easier to figure out.

Good idea, I can't believe I didn't do that yet.

I did the ring gap before building. I can measure to the top of the port now without pulling the Cyl, so I'll check that before pulling it. You think the crosshatch looks worn?

It's the old style head, I'll get close up pics later it's at a friends place now

It's the reflection from the WD40 on the piston crowns on the super shiny cylinder walls

Ride plate is M8 1.25

About an 1 1/2. There are a bunch of peeps on here that would send or sell you some.

Checked the squish. Both holes are reading right around 1mm

Yeah I will do that, and I'll post the readings. The head was not leaking and all orings were sealed when the head was removed

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