I've built a lot of hobbits. The Athena and the fast arrow and the 77 cast iron and the wizzard (which is actually same as the fast arrow, TCCD, and 77 aluminum kits) all required some spacing. I almost wonder if some euro cylinder or the china clones was decked differently, because why would so many kits be so consistently off?
Regardless, I've run the malossi cast iron, polini iron, DR, athena, fast arrow, and 77 cast iron kits, as well as the "stocko shocko"
the 77 generic ones are absolutely the worst, stockoshocko is worthless, ported stock is infinitely better thna either of those.
Beyond that, malossi, polini and DR are all quite similar in performance, but the DR is just a way better value, and it takes a hell of a beating without complaint.
And the athena, without question was the fastest, all around, torque and rpm, unreal. but yea, finicky.
Really wanna try the metrakit derbi setup, expecially for the better cooling, and curious about the malossi H2O, but i'm gonna shut up now and leave with this to say
DR is the best value, easiest, most rewarding and most robust kit for the hobbit. with porting it'll shred with the best of them, but even as recieved it's a really great kit. it may be my favorite kit in all of mopeds.