To properly compare the 2 motors you need to have identical props on both and remove the ducts. Ideally this should be done with a constant power supply and in a tank so that accurate figures can be achieved.
I have found with real world tests there is always inaccuracies because of water movements and differing battery voltages etc.
But right from the onset you can see that the FR motor will be way better because it has a wider rotor with more poles, much better construction and better bearings. This will translate to more torque and thus better efficiency…
Hi.
To remove the thrust bearing you need to remove the back plate with the wires. Yes. Those screws on the side must be removed. Be very careful with the motor wires. It is easy to break the insulation. The wires are secured and waterproof in the back plate with that plastic cover. Remove that cover. You will find that each wire has two o-rings. I found silicone greasing the wires helped slide the plate and o-rings off.
When putting back together silicone grease the o-rings and hole and after bolting the back plate onto the motor slide each o-ring down the wire and push them into the hole, one at a time. Be careful not to push them all the way through. You must get the o-rings started in the hole by hand. Don’t trust the plastic plate to push the o-rings in.
I used silicone grease behind the plastic plate, and Tef Gel on all the screws.
Once you have to plate off, you should be able to work the bearings out. If you can’t get them out go buy, or borrow a “bearing puller” or “pilot bearing puller” tool.
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Yeah I understand this. I was under the impression people were using FR props on the Chinese motors and was just looking for real world feedback not accurate data.
I’ve used both and there are graphs with both on the forum. You’d just have to search for them. I can’t even remember exactly where I posted some of them, but some would be here, then on the FR thread and then some in my build threads.
Before you remove the bearing, take a dowel or something long enough and test the bearing. Then add some corrosion X and test it again. If its runs smoothly then your bearing should be fine. But considering your rotor is touching the magnets, I suspect you will still have some noise even if your bearings are fine…
Thanks! Well I had a couple of rides with ow noise, now I have the noise. So something must have happened. I will try to test the bearing before but I did already sprayed it with corrosionX, re assembled and test again with same finding.
Thanks for the explanation. I will try my best, but maybe I should already consider to order a new one 
nah challenge accepted.
Is it possible that one of the magnets has come loose?
It’s a Chinese bearing. That bearing being bad is the only way things will rub.
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Ben, the MIT guy, is looking for new motors to test. Who in the US wants to send his FR motor for a couple of days to Massachusetts ? 
Have a motor you want characterized? Hi. I’m Ben. I like to to build things and write about the things I build. I work in the Biomimetic Robotics Lab.
You can get in touch via email with the form below:
https://build-its.blogspot.com/p/about.html
That man won’t bother testing it. He has been quite busy building himself all the motors of Boston Dynamics’s cheetah (for the record, Google acquired Boston Dynamics end 2013…).
Plus, on some other posts he’s playing with $10k motors. He would have no problem buying one and testing it if he really was interested
Deep groove ball bearing = not a thrust bearing.
Okok, I got to the inner part. Seems like the bearing has a dent. Right on 6001z marking.
Need to get out now
Is it running badly or smoothly? I’ve dented countless skate bearings but it hasn’t affected how they’ve run…
Is there enough play to make rotor hit the stator?
The bearing sounds not good when putting stator in and turning by hand. How the stator hit the side? No clue
Is there play in the bearing or just a rough sound? Check the stator to make sure there is nothing that can catch the rotor while it spins…
This is quite hard to tell. I will just try to replace the back bearing. I have ordered some high quality 6001z ones already to be sure to match the actual one. If you have Recommendation for other type of bearing feel free to share it. Also I would like to clean the motor, remove existing grease and replace with good one. Would isoprop work on these motors to clean them? Maybe I also have to smooth the stator since there are fibers from scratching sticking out. Btw still waiting for Flipsky reply
Is that really a thrust bearing? It doesn’t look like one. Should we be using a thrust bearing between the prop and motor? I have the same motor on order.
@Flying_Rodeo Are you doing another run of props for the 65161? I’d love to get my hands on a half dozen.