Hi Ken,
Thanks for your input.
Your point was sort of what I was asking about.
after a bit of digging, here is the answer(s).
this might help others.
it's simple stuff, but not written down anywhere in the riders Handbooks, or the R & O manual. And, if you look at the parts book, it is confusing with individual part numbers for each of the 4 pushrods; meaning each pushrod is somehow different, but not explaining or illustrating the difference!
Here's how it goes:-
The pair of Short Push Rods got to the Rear cyl.
The pair of Long Push Rods go to the Front cyl.
Of each pair, one pushrod has an oil groove down it, & this grooved pushrod goes for the Exhaust.
So, each pair of pushrods is different in length, & of each pair, one has an oil groove & one has not. Hence 4 different part numbers.
It makes sense once explained.
Maybe this will help someone else as well.