There are two valves on each rocker arm. It's difficult to see if only one valve is sticky.

 

Maybe a candidate for adjustable rocker arm?

 

IMO, with only 700 ish miles on the engine I feel it's unlikely there's a valve hanging open due to carbon build up on the valve stem. For enough carbon to build up that quickly I believe you'd have seen clear evidence of oil burning coming out of the muffler. But the "sputtering" you mentioned does suggest a miss fire. Did the sputtering turn into a constant thing? Loss of power?

Sounds like a bad lifter to me, too. While you have the rocker covers off lightly press down one of the arms, or pull up on the push rod end, and check clearance at both valve tips. Ideally there should be none on either.

 

Well, I did a leak down test on the bike and it was showing 90% loss. I thought I messed something up during the setup so I repeated the test with the pushrods removed and got the same result. Sounded like the air was coming from the intake manifold/throttle body.

I then pulled the head off the leaking cylinder. There was a lot of oil build up on the intake runner and combustion chamber. Im going to clean it up and see if I can find the leak.

Other than that, anyone have any other suggestions?

 

Have seen reports in here of the factory fitting the scavenger piston ring upside down. I'd guess very rare, but might be the problem?

 

With only 720 miles on it why did you tear it apart instead of taking it to the dealer?

 

If air was leaking into the intake it has to go past the intake valves to get there.