Bafang G310 clutch not engaging?

[Bush mechanic]

Anyone using the small Bafang G310 or G311 geared hubs, have you had issues with the clutch either intermittently or completely failing to engage?

This was kinda funny at first as it happened only very occasionally, motor would spin freely like you were revving a bike, with a turbo spool sound, and upon releasing the throttle it would engage again, but it has become progressively worse to the point it takes 3-4 attempts to get the clutch to engage.

I've replaced gears in the past on the G310 so I'm not too worried about taking it apart, just wondering if anyone has had this and what I'm likely to find in there this time.

NB. I don't think it's the gears being worn or damaged, as it seems to run fine once it engages.

 

[amberwolf]

Depending on the clutch design, it could either have a crack in the main body of the clutch itself (I broke an old Fusin this way), or more likely the rollers could have flat spots on them (from clutch slips from overtorque events) that sometimes end up all on the clutch surface so they don't have as much grip...but sometimes the round parts line up and it gets more grip.

 

[Bush mechanic]

Depending on the clutch design, it could either have a crack in the main body of the clutch itself (I broke an old Fusin this way), or more likely the rollers could have flat spots on them (from clutch slips from overtorque events) that sometimes end up all on the clutch surface so they don't have as much grip...but sometimes the round parts line up and it gets more grip.

Sounds like that = new clutch assembly. I'm still kind of hoping it just needs a clean up and that it might be some hardened grease etc but that sounds like it could make sense I wouldn't say it works terribly hard but it is only a tiny motor. I'm putting off taking it apart because it is damn freezing outside .

 

[anzlksf]

Sounds like that = new clutch assembly. I'm still kind of hoping it just needs a clean up and that it might be some hardened grease etc but that sounds like it could make sense I wouldn't say it works terribly hard but it is only a tiny motor. I'm putting off taking it apart because it is damn freezing outside .

Hi Did you resolve this issue? I ask as I have the same issue on a G311.

 

[Bush mechanic]

Hi Did you resolve this issue? I ask as I have the same issue on a G311.

Hey mate I haven't logged on for a while and just saw this, I'll post an update in case you or anyone wants to look into this further.

The short answer is no, not resolved as such unfortunately, however, I did in fact pull this motor apart a few days ago and I noticed that there is a physical issue with the clutch pawls which are allowing it to slip. I'm not sure if you have ever taken one apart or are aware of how the clutch functions, but basically it consists of a large number of small steel wedges (pawls) which rest against the inside of the clutch ring at an angle, with a small spring pressing each pawl outwards against the ring. Due to the angle, the ring can easily turn in one direction as it pushes the pawls inwards with a negligible amount of drag, however, when force is applied in the other direction it jams the pawls into the outer ring - ie the clutch engages and locks into place.

The springs and pawls are held in place by a plastic retaining ring, and what I found was that this ring had popped out, allowing several of the springs jump out of their position meaning they no longer applied pressure to their pawls. At least one spring had broken.

I was able to verify intermittent slipping by forcefully turning the motor from side to side, to emulate free wheeling in one direction and engaging in the other. Most of the time the clutch did still engage, but intermittently I could see and feel it slipping when I did this, which is entirely consistent with what I am finding when riding. You need to very VERY carefully use a small tool to push each spring back down into position, and then press the retaining ring back down, but sadly even after doing this mine has continued to slip. Watch out - they like to jump out and they are tiny, and their natural abilities to camouflage themselves from predators on carpet is remarkable. Ask me how I know...

I did notice that my plastic retaining ring is a dit deformed (probably due to me previously disassembling the motor and being too rough) so it's possible that some of my springs have jumped straight back out after reassembly, or, it could also be that there is enough physical wear on either the pawls or the clutch housing that they can no longer 'lock' into place firmly enough. Something that could be done perhaps would be to lightly sand the inside of the clutch housing to make the surface a bit rougher or to remove any uneven spots that might be contributing to the pawls not engaging quickly enough, but I have not tried this.

I am convinced however that this is a clutch issue and not an electrical issue as has been previously suggested (where the motor is supposedly spinning backwards). I do need to reiterate that my G310 has been worked much harder than it should, fairly low mileage but I'm 100kg and I push it at 1KW up hills for short bursts. I've gone through 4 sets of gears in as many years so I know I'm pushing it beyond its intended limits, so I'd have to accept that physical clutch wear might be the underlying cause for me.

I'll try and attach a couple of photos of the inside of the motor in case this helps anyone at any stage while troubleshooting. There may be other explanations as well, but in short, pawls failing to reliably engage leading to clutch slippage is what I'm putting my issue down to.

 

[m_cremers]

This was very informative man, thank you.
I am currently trying to figure out wether my motor has an electrical problem (spinning backwards) or if it's a clutch issue. Sadly after having tried a million phase/hall wire combos it has made all sorts of noise but has not spun once. Thing is, it has no throttle so I am using walk assist for testing but cant imagine how walk assist would engage the clutch normally.

Im a complete noob and have never done any of this before so any help os much apreciated!

 

[amberwolf]

First, I recommend you let me move your post and my reply out to it's own thread, so we can troubleshoot your problem separately from this thread's OP and not confuse the thread with two different things.

Next:

I am currently trying to figure out wether my motor has an electrical problem (spinning backwards) or if it's a clutch issue. Sadly after having tried a million phase/hall wire combos it has made all sorts of noise but has not spun once. Thing is, it has no throttle so I am using walk assist for testing but cant imagine how walk assist would engage the clutch normally.

Your best bet is to:

Put the wheel into the dropouts of your frame if it isn't already (if it isn't then when you do get it spinning it's going to rip your wires apart and damage them when the axle spins instead of the hubmotor and wheel). Make sure to install and tighten all the axle nuts and torque arm hardware.

Manually spin the wheel forwards. It will feel easy to spin, if the clutch is disengaged as it should be.

Manually spin the wheel backwards. It will feel harder to spin, if the clutch is engaged as it should be, and you may hear the motor core spinning inside the hubmotor shell, being forced to spin by the clutch and planetary gears.

Regarding walk assist, all it does is spin the hubmotor at a constant slow speed while you hold the button, for any system I have used. It doesnt' matter if there is a clutch or not, or even if the clutch is broken. It would still spin the motor itself even if the hubmotor shell and wheel don't spin.

 

[Bush mechanic]

This was very informative man, thank you.
I am currently trying to figure out wether my motor has an electrical problem (spinning backwards) or if it's a clutch issue. Sadly after having tried a million phase/hall wire combos it has made all sorts of noise but has not spun once. Thing is, it has no throttle so I am using walk assist for testing but cant imagine how walk assist would engage the clutch normally.

Im a complete noob and have never done any of this before so any help os much apreciated!

Hi there, sounds like a very frustrating situation - just to confirm are we talking about the same motor, a Bafang G310 / G311?

I am by no means an expert but I will say that clutch issues are really quite uncommon compared to the myriad of electrical problems that typically occur with ebikes, involving anything from loose connections to incorrect phase/hall combinations or compatibility issues between your components.

Starting a new thread as AW suggests is a good idea, you'll get more exposure that way, and if you can provide some info on your system there is a good chance it can be resolved.

 

[m_cremers]

Hi there, sounds like a very frustrating situation - just to confirm are we talking about the same motor, a Bafang G310 / G311?

I am by no means an expert but I will say that clutch issues are really quite uncommon compared to the myriad of electrical problems that typically occur with ebikes, involving anything from loose connections to incorrect phase/hall combinations or compatibility issues between your components.

Starting a new thread as AW suggests is a good idea, you'll get more exposure that way, and if you can provide some info on your system there is a good chance it can be resolved.

Thanks guys, I'll stick to the dedicated thread. @amberwolf I'll also post an update on the old one. I do feel like im progressing. Thanks for the help.

@Bush mechanic this was actually very useful.info as I had no idea how these clutches operate. Thanks for sharing