Just in case there's someone out there who had the same expierience I had with gears grinding and making noise read on. There's an upper steel collar just behind and above the motors on the rotor shaft. Its function is to hold the rotor shaft up so the pinion gears on the motor shafts meshes properly with the drive gears on the rotor shaft. If this collar shifts even slightly the gears don't properly mesh and gear grinding and slipping can occur. Loosen the set screw on the collar,lift up onthe rotor shaft then slide the collar down on the shaft so that the gears mesh well and the collar is snug against the plastic rotor shaft holder(I know this sounds confusing so work with it and you should be able to figure it out) While holding up on the rotor shaft assembly tighten the collar set screw. If you did this correctly you should be able to pull up on the rotor assembly without the rotor shafts moving up and down.
Loosen the set screw on the collar,lift up onthe rotor shaft then slide the collar down on the shaft so that the gears mesh well and the collar is snug against the plastic rotor shaft holder
But not too snugly. Ideally, you should feel (but not see) just the tiniest bit of play in the shaft with the collar properly seated; if it's too tight, you can get binding that will severely shorten your flights and can shorten the life of your motors and 4-in-1.
I’m new to the forums and fairly new to the sport of RC Helis and this looks like a great place to learn and help others learn. I’m having a similar problem with my Blade CX2 and was hoping someone could help.
I can only get about 12 inches off the ground and my heli is spinning to the right slowly. I’m adjusted the trim and proportional and that’s not helping. I’ve checked and the battery is fully charged and I’ve replaced the inner and outer shafts. I just ordered a new 3 in 1 and I’m hoping that will solve the problem.
Here’s my question; most of the people here have said the problem can be solved by replacing the 4 in 1, but the 4 in 1 consists of 2 parts; the 3 in 1 and the receiver. To solve the problem, do you need to replace the receiver too, or just the 3 in 1? I wouldn’t think the receiver would get damaged as easily as the 3 in 1.
Thanks so much for your post.
I spent ages trying to figure out what was wrong until I finally started checking on line and found your answer. ( I had just replaced my bottom rotor collar for the 1st time.)
Your suggestion worked like a charm, I tightened up the screws on the collar at the bottom of the shaft, just above the battery, and all was good again.
perry, don't get a big ego , but i found that the locking collar on the bottom gear has 2 threaded screws that go through the little holes on the gear and lock onto the flat spot on the inner shaft. it looked tight but when i held it and spun top blades, it spun.
I had the exact same problem as you. I found that my outer shaft had a very slight wobble so I replaced it and gave all the bearings a small shot of WD40 and it ran again like it was new. Not 100% sure if it was the Wd40 or the new shaft that fixed the problem. Hope this helps you.