​​​​In the piccy

Pretty obvious, I won't ruin it.  I can understand why it may have been done that way.

Good evidence as to why it's a bad idea to use parts diagrams for assembly. 

Hmmmm…. interesting!
If it wasn’t there would they know what to do?

Or would they blindly follow the diagram?

Would they question what was on the actual part?

There is a contradiction in the drawing. It shows what is actually on the part correctly but someone possibly took "creative license" to show a feature that would otherwise be hidden? I've seen that quite a bit in diagrams.

Piston orientation, perchance? 

I guess it ranks alongside the RD125 parts book, which shows the battery box fitting on the wrong side.   

I didn’t see it immediately truth be told - and I won’t spill the beans. But yeah some ting is definitely amiss …

a

Is this immediately obvious to the layperson?

The only thing I can think of, not being super familiar with the mechanism, is that there's nothing locating the piston rod to the crankshaft in the transverse direction i.e. it can slide up and down the crankshaft (it wouldn't, because of the piston being held in place by the bore, but it could still move in a way that's not intended)

Also piston direction looks right to me I think?

piston is backwards

pissing tin back ta front without looking hard. maybe drew it that way as can't show the holes other way around.
Just put the cylinder on backwards that'd fix it.

Maybe for a twin carb prototype