In order of likelihood, I's suggest, pedals, freewheel (looks like a shimino), bb.
As a general point, I'd suggest chain cleansing / lubrication, check chainring bolts and check no tight spot when rotating the crank.
I don't understand why peple don't like the half link. It is much more airodynamic than an ordinary chain (at leaast if you had it on the other way round).
In order of likelihood, I's suggest, pedals, freewheel (looks like a shimino), bb.
As a general point, I'd suggest chain cleansing / lubrication, check chainring bolts and check no tight spot when rotating the crank.
I don't understand why peple don't like the half link. It is much more airodynamic than an ordinary chain (at leaast if you had it on the other way round).