Help me understand this piston ring clocking diagram

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WildCoast

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From here: https://cdn.shopify.com/s/files/1/2...TION_INSTRUCTIONS_09-13-2023.pdf?v=1694606490

I can see that they want the gaps offset by 90 degrees, but I can't tell what the piston orientation is?? I'm guessing the round shapes on the piston surface are supposed to be a hint, but I'm not sure. Is the bottom of the diagram the exhaust side of the psiton? So the horizontal line is the pin axis?

In general, there seems to be so much different advice in terms of how to orient the 2 top rings as well as the 2 rail rings which make up the oil seal. Some say to put the 1st ring gap facing the exhaust, while others like the Wossner documentation seems to want everything offset by 45 deg. What gives??

For context this is going into an XR650L Honda dual sport.
 
WildCoast said:
View attachment 344914
From here: https://cdn.shopify.com/s/files/1/2...TION_INSTRUCTIONS_09-13-2023.pdf?v=1694606490

I can see that they want the gaps offset by 90 degrees, but I can't tell what the piston orientation is?? I'm guessing the round shapes on the piston surface are supposed to be a hint, but I'm not sure. Is the bottom of the diagram the exhaust side of the psiton? So the horizontal line is the pin axis?

In general, there seems to be so much different advice in terms of how to orient the 2 top rings as well as the 2 rail rings which make up the oil seal. Some say to put the 1st ring gap facing the exhaust, while others like the Wossner documentation seems to want everything offset by 45 deg. What gives??

For context this is going into an XR650L Honda dual sport.
Click to expand...
The larger ellipses should point to the intake valves while the smaller ones should point to the exhaust valves.

MolaKule

Thread 'Exhaust and Intake Valve Diameters'

In terms of Gas Dynamics (such as flow velocity, thermodynamics, piston crank angle, and pressures), explain why the Intake valve has a larger diameter than the Exhaust valve.

Assume a naturally aspirated, single-cylinder, spark ignition engine.

Rule number 1. We will not criticise each other's answers since we will deal with clarifications later.
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The round shapes are the insets for the Valves. If you know which valves are larger and smaller, you'll know the orientation. The horizontal line should be the pin axis.

All that said, rings don't stay stationary...they rotate as the engine runs. So it seems that the orientation is to facilitate installation...but they don't retain that original orientation.
 
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