So, i changed the oil pan gasket on my brat and noticed a orange o-ring in pieces there. I assume it's the same as in this pic.

Now the question, where's it from and how hard is it to put a new one?

I tried looking from exploded view thingys but couldn't find it.

That is from the water passage between the 2 block halves.

 

If there is now no o-ring up there, you may get water leaking into the oil.

 

There is also an orange o-ring at the back end of the crank, under the flywheel/flexplate.  But I can't see how that would get to the oil pan.

 

Sure it's not Orange RTV?

That is from the water passage between the 2 block halves.

 

If there is now no o-ring up there, you may get water leaking into the oil.

 

There is also an orange o-ring at the back end of the crank, under the flywheel/flexplate.  But I can't see how that would get to the oil pan.

 

Sure it's not Orange RTV?

Oil was oil when i drained it and changed the crank seal and the orange o-ring was there.

could be that rtv stuff. Probably just freaked when i saw the orange bits and had the orange o-ring in a box next to me.