Had the S107 (yellow) for a while now and it unfortunately fell off the shelf and broke the top section off the rotors (the bit that holds the counterbalance on top of the inner shaft thingy)...
Been trying for ages to find replacement parts, then amazon saves the day! Hooray! Rapid service, up to the usual standard with 1st class post (not that awful courier company that loses things or is so late you've retired before your stuff arrives!).
The kit DOESN'T come with the locating pin that holds the counterbalance in place, and my original is thinner than the replacement part so it drops out with no effort.
The replacement inner shaft is thinner than the original, thus the top section will not fit onto the original shaft, or if you use the replacement shaft it is too thin to fit the drive gear & engage into place. It's so thin in fact that it falls straight through and out the bottom of the aircraft.
1. Used superglue to hold the counterbalance locating pin in place. Time will tell if successful.
2. Used a tool (tiny drill bit and/or thin watchmakers screwdriver) to ream out the replacement top section so it fits onto the original inner shaft.
Very disappointed with this kit as replacements. I've only needed the top section of the inner shaft and found it, and the shaft, to differ from the original. I've not even tested the other items in the kit.... yet. One shouldn't have to re-engineer a solution with matching 'genuine' parts surely?
Apart from that, the helicopter itself is superb! Hooray, I'm airborne again!