here’s my .02 on tracking…first, as previously posted, balance the blades…use red/black/blue balancing tape…at a hover, one blade might be flying higher than the other, i.e., the red blade is higher than the black blade (you can see it clearly under the right lighting conditions)…you can either increase the pitch of the low blade or decrease the pitch of the high blade…i recommend lowering the high blade by shortening the pitch control link, which will decrease the pitch…it’s safer to shorten the link, so that you’re assured that you won’t run out of threads…the engineer who designed the hbk2 specified that the link have a nominal length of about 57mm…us pilot/mechanics shouldn’t deviate from that too much…
-ken