EvikeCYMA Sport Complete Ver II Gearbox w/Quick Change Part for M4 Series AEG Airsoft (Type: Rear Wired/High Speed Motor)

Update: 4/26/25I’ve had nothing but issues with this gearbox. First the gears sheared off so I replaced and shimmed the gearbox correctly, then the cylinder head broke, the plastic head splintered and the metal inner air nozzle was just free floating, so I replaced that, and now the semi-auto sensor failed so I’ll have to swap in a new trigger system. Full auto works, but when the semi auto lever moves in front of the sensor I get a runaway motor that triggers the fault cutoff after about a second.My AEG is pretty plain (well not anymore after all the upgrades I did replacing parts). I only run 7.4v batteries, nothing crazy. This is by far the most fragile gearbox I’ve ever come across.I originally gave two stars because the gears broke after about 20 rounds. But then the cylinder head and semi auto sensor failed too? I had to reduce it.Original review:I finally got around to building my rifle, and I installed this gearbox in my AEG and used it once and my rifle stopped firing BBs. So I opened up the gearbox, and one of the gears had 7 teeth broken off/damaged. I had fired maybe 20 rounds, semi-auto to sight in my optic, not even close to a whole magazine. I thought if anything it would have been the bevel gear since I had to adjust the motor to mesh with it.I don't have a super high rate of fire rifle, or crazy parts or anything, just a normal AEG so it's odd that this would have even been an issue. I guess my first upgrade will be a new set of gears that I’ll shim myself. I should have done that in the beginning.Now to be fair AFTER this happened I still ordered another gearbox (same one) with plans to swap the gears anyway, I will try it before swapping anything just to see if the gears hold up to a bottle of 2k BBs. If they do I will probably increase my review.PROs: I like the quick change spring system.

Excellent Gearbox and Fast Shipping!I’m really impressed with this CYMA Sport Ver II gearbox. The build quality is solid, and the quick-change feature makes it so convenient for adjustments. It fits perfectly in my M4 AEG and performs flawlessly with a noticeable boost in speed thanks to the high-speed motor. It arrived earlier than expected, which was a great bonus. Highly recommend for anyone looking to upgrade their airsoft setup!