Onyx 4000kv motor rebuildable?

[Heisenburg]

I have an old Onyx 1/10 4-Pole ESC/Brushless Motor Combo 4000Kv 3.5mm Bullet EC3 ONXS0501 that came with a used Rustler I got years ago. Not a bad little motor, but it's chugging off the line at low throttle input. I thought I might rebuild it. I can't find a kit specifically for this motor, is there a kit that will work?

 

[CreepyQuarryCrawler]

Cogging for a sensorless system is completely normal. The ESC bumps the motor trying pick rotation feedback and then the ESC tries to apply power in the right direction.

Higher gearing will make the problem worse.

 

[RustyUs]

I have an old Onyx 1/10 4-Pole ESC/Brushless Motor Combo 4000Kv 3.5mm Bullet EC3 ONXS0501 that came with a used Rustler I got years ago. Not a bad little motor, but it's chugging off the line at low throttle input. I thought I might rebuild it. I can't find a kit specifically for this motor, is there a kit that will work? View attachment 273959

I don't know how bad your cogging is, but most likely its normal. I doubt you'll find specific Onyx replacement parts. Except for replacing some sensor boards, rotors and bearings, I don't really classify brushless motors as "rebuildable". Even if you find, by chance, a rotor that fits, it'll cost just as much as a new motor and still left with the cogging. That combo looks like the many Hobbywing RTR rebranded units from 2012-ish that were in many RCs. I think some sensorless ESC/motor combos have better motor startup circuitry algorithms (whatever you want to call it) than others.

 

[Heisenburg]

I was going to try and replace the end bearing. I rebuilt a Velineon Traxxas and it cured the problem. This motor also has a unique "whippling" winey kind of noise as it accelerates. I'll probably just replace it as it sounds like it is a "dixie cup" throwaway cheap option for replacement yestrerday

 

[CreepyQuarryCrawler]

You can absolutely try and replace the bearings.

I believe your question was two parts and I just kind of answered it very generic like.

 

[Heisenburg]

Any ideas where to find a bearing kit for this?

 

[CreepyQuarryCrawler]

Your best bet would be to use a caliper and measure the diameters if the bearings of you cannot find the specs. You'll need outside diameter, internal diameter and the width.

If you suspect they're bad I would just start with disassembling the motor and check them out.
If they feel gritty in your fingers when you turn them you're on the right path.

Calipers can be had very inexpensively these days through places like Harbor Freight or Amazon.

For individual bearings I usually just go to my LHS. If you don't have one then you'll have to buy them online.

Good luck Mr White