So the starter is free spinning when it stops cranking the engine , so it kind of whirrs ?? , like it is disengaging and the starter is still turning but the engine stops turning ?? , then once in a while it engages and starts right away ??
With 15 hours , I would call the dealer and tell them what it is doing , I know the 18's were having some issues with the starter clutch , but I have not heard about the same issues with the 19's or 20's ... I have had zero issues with my 20 , never a issue at all with running , 74+ hours , and the only issue I have had is I wore completely thru the chain guide ... I talked to Kris Keefer about it and he told me he only gets about 30 hours on his sliders and guides , I have gone thru 3 chains , and am on my 3rd set of tires .... but not one hiccup with electrical , or engine ... and like I mentioned , the only "issues" I have heard is the same since the 17 , you get the kill/map switches wet and they short out and have to be replaced .... other than that , I think the 20 is better than the 21 as I have ridden the 19 , 20 , 21
But I would definitely contact the dealer , or even contact Honda themselves and see if/what they will do (try the dealer first) , it should not be having any starting issues , especially with that little bit of hours , if the Dealer is cool , they should look into it and hopefully get Honda to warranty it ...
I would recommend this bike to anyone ... it is hands down the best bike I have ever owned (I will be 62 next week and have not ridden anything better in any brand) , just set the sag at 108 , put the forks flush with the clamps and use Kris Keefer's settings for the clickers , and if you are over the recommended weight (I am 190) get the next up in springs (0.52/5.
so you don't bottom out on landings and G-outs , it is even plusher with the stiffer springs ... I also put a flywheel weight on it to get rid of the teeter totter when going into and out of corners (it has way too much compression braking) , and re-geared it 14/52 ( am just switching it to 14/51 now to mellow it out a bit after I put the Titanium Yosh system on it
But back to the point .... This is a really good bike , and it must be some odd defect that got thru with the starter one way bearing or something , like maybe it was a leftover gear from the 18's , but I would double check the one way gear and make sure it is actually locking up (it should lock in one direction and freewheel in the other) , if you can't get it to lock then it might be the issue since you pretty much checked everything else in the starting system , my guess would be the one way bearing/gear