Giant Twist Lite motor issues

[Stoke]

Hi all, great forum but first time posting.

I have a Giant Twist lite that was making some bad noises from the front hub motor.

Stripped it all down to find about 20ml of water that had ingresed the motor housing and subsequently distroyed the motor bearings.

Now I've searched high and low and parts seem to be quite scarce for this bike. Found a motor in Norway and a site in Holland that has a few bits.

Basically I wondered if anyone else had replaced the bearings inside the motor itself on this bike?

It's the bearings inside the motor that I need to replace. There's two inside one at the top and bottom of the shaft.

The bearing at the top of the shaft I can just read the numbers (69027 I think) shown in the first pics.

However the bearing at the bottom was completely distroyed as you can see in the pictures.

Does anyone know if replacement bearings can be sourced or perhaps a replacement motor? Shaft length is 145mm.

Giant are useless btw.

I can upload more pics if anyone is interested.

 

[esuark]

think that's 6902Z

 

[flecc]

If the three dimensions shown match, probably this one:

Bearings | Shop Bearings | Leading Bearing Brands | Online Bearings

You do need the number in both cases to buy from a bearing factor, but hopefully they are both the same.
.

 

[Nealh]

One can source sealed bearings on ebay or many other outlets like simply bearings .co.uk.
The 69027 as said will likely be 6902z or have a look for 6902rs check all the measurements carefully against your one. Over all dims, internal dim and thickness.
The central shaft one if a larger dia could be anything again something like a 6811rs, one needs to search different sizes to match any dims you can glean from your broken one.

 

[Nealh]

The other thing one needs to find out is why the hub filled with water ?
Was the hub installed with the motor cable exiting out of the top of the axle ?
If so then water tracked down the cable, the cbale needs to exit under the axle then form a drip loop before going up.

 

[Stoke]

Fantastic replies thanks everyone. Managed to get the outer races removed this evening and there's actually 3 X bearings in total. Weird though there's 3 outer races and only 2 inner! Just need to find a puller now that I can remove this inner race out now. Thanks again for your replies.

 

[Stoke]

The other thing one needs to find out is why the hub filled with water ?
Was the hub installed with the motor cable exiting out of the top of the axle ?
If so then water tracked down the cable, the cbale needs to exit under the axle then form a drip loop before going up.

Great tip, I'll make sure of this when I reinstall it.
I don't think there was much of a seal around the hub either. Seems like there was a small amount of silicone sealant like material. Any recommendations for when I do reseal it?

 

[Stoke]

One can source sealed bearings on ebay or many other outlets like simply bearings .co.uk.
The 69027 as said will likely be 6902z or have a look for 6902rs check all the measurements carefully against your one. Over all dims, internal dim and thickness.
The central shaft one if a larger dia could be anything again something like a 6811rs, one needs to search different sizes to match any dims you can glean from your broken one.

Thanks, ordered a set last night and a bearing puller. Fingers crossed it all works as Giant wanted to sell me a complete wheel for £250

 

[Nealh]

If you feel the seal is poor then one could try some gasket seal to form an impervious seal.
Is the hub screwed together as two parts or does one side have a face plate screwed side fixing ?

 

[fwmgaok]

hi all, i found this site and article forum discussion whilst researching via google. i have a giant Twist Lite 2 GTS L Antracite/Satin Silver whit a similar noise problem, the motor does not engage as well. the inside has gears made from nylon, is a planetarium system with a small electric circuit board which works out when to engage and not.

So far I found a cable connector had melted when I took the box/cadence box/box with the resin covered and secured in a metal/aluminium/stainless steel case located just past the bottom bracket shell. I cleaned the connection up and reconnected the damage in wiring but that hasn't made any difference.

I spoke to a technician who at first hearing the motor reckons the motor is gone. so we opened the front hub motor casing to investigate the inside for any broke gears or water damage, all seemed fine except some of the gears did not seem to engage when manually turning by hand. but all seemed fine when we got back to it a few days later so we put all the units back together but the issue persists.

I then spoke to a giant dealer mechanic who reckons might still be the motor or an electric fault such as a poor current/power delivery to the motor so my troubleshooting continues. any help and advice appreciated, also if anyone knows how to install an accelerator and/or remove the speed limit that would be greatly appreciated too

 

[saneagle]

hi all, i found this site and article forum discussion whilst researching via google. i have a giant Twist Lite 2 GTS L Antracite/Satin Silver whit a similar noise problem, the motor does not engage as well. the inside has gears made from nylon, is a planetarium system with a small electric circuit board which works out when to engage and not.

So far I found a cable connector had melted when I took the box/cadence box/box with the resin covered and secured in a metal/aluminium/stainless steel case located just past the bottom bracket shell. I cleaned the connection up and reconnected the damage in wiring but that hasn't made any difference.

I spoke to a technician who at first hearing the motor reckons the motor is gone. so we opened the front hub motor casing to investigate the inside for any broke gears or water damage, all seemed fine except some of the gears did not seem to engage when manually turning by hand. but all seemed fine when we got back to it a few days later so we put all the units back together but the issue persists.

I then spoke to a giant dealer mechanic who reckons might still be the motor or an electric fault such as a poor current/power delivery to the motor so my troubleshooting continues. any help and advice appreciated, also if anyone knows how to install an accelerator and/or remove the speed limit that would be greatly appreciated too

If the motor connector melted enough for the wires to touch, you can blow the MOSFETs in the controller. You need to do some tests with a meter. Can we see some photos of where the wires melted and the controller with all the wires coming out of it?

 

[fwmgaok]

Hi @saneagle , thanks for reaching out. Took a picture today and to answer your question it is the green cable ( which runs from the main control box to the motor) and its connector that i found melted badly, sticking onto the red connector of the yellow cable which is luckily intact.

 

[saneagle]

Hi @saneagle , thanks for reaching out. Took a picture today and to answer your question it is the green cable ( which runs from the main control box to the motor) and its connector that i found melted badly, sticking onto the red connector of the yellow cable which is luckily intact.

That doesn't look too bad. The only question is whether any conductors touched. If any of the three main thick motor wires touch in operation, the first thing would be a rasping noise from the motor and rough running, like gears are not engaging properly, then you'd get intermittent running. If you keep going in that state, the MOSFETs in the controller blow, so that's the first thing to check. It's very easy. Here's how to check an ebike. The MOSFET test is no.6. If that gives an OK result, you need to test the hall sensors (no.5). You do that with everything switched on. First remove the glue from the back of the connector, then stuff your probes up the back where the glue was. It's the connector with 5 thin wires (red, black, blue, yellow, green). You need a multi-meter. Without one, you have no chance of sorting out your problem.

1. Measure the voltage at controller's battery connector. Obviously should be battery voltage. 36v - 42v for a 36v battery would be an acceptable range, but if you've fully charged the battery and it's less than 41v, it needs some sorting.
2. Measure the voltage on the 5v rail. You can measure that between any ground (black) and any of the reds going to throttle, PAS or motor halls. It should be around 5v.
3. Check throttle signal wire voltage on it's connector while connected. it's the wire that's not red or black on the throttle connector. Should give about 1v to 4v when you twist the throttle. If there's more than one wire, your meter will find it. It's the one that's between 1v and 4v, assuming that it works.
4. Check that the pedal assist sensor is pulsing. Measure the PAS signal wire while turning the pedals slowly. Should pulse 5v on and off every time a magnet passes the sensor. The signal wire is the one that's not red or black.
5. Check the motor hall signal wires (blue green and yellow) on the motor connector at the controller. They should each pulse with 5v going on and off as you rotate the wheel BACKWARDS.
6. Mosfet test. Disconnect the motor cable and battery from the controller. Measure the resistance (200k scale) between the red battery connection and each of the three phase wire connections, then repeat with the black battery wire. Each set of 3 readings should be the same as each other and in the range 7K -24K. Though can be higher as long as they're all the same. Due to the capacitor across the battery wire, you can get a constantantly changing measurement while it charges. In that case, try swapping your probes round. Even though can be a moving result, the only important thing is that all three move in a similar way.

To test whether it's working, you should disconnect everything that's not needed, like Pedal sensor, lights and brakes. Listen for a tick or click from the motor when you operate the throttle, which indicates incorrect timing of the power pulses caused by incorrect connection sequence or faulty connection in the motor cable.

With any ebike, never continue to give the motor power when it's not running smoothly or not running at all. Just because you can't see, feel or hear anything happining, it doesn't mean that nothing is happening. Eventually, the smell of burning will give it away, but then it's too late.

 

[fwmgaok]

Hi @saneagle the bike is a pedal assist type so no throttle, the motor kicks in when pedalling.

 

[saneagle]

Hi @saneagle the bike is a pedal assist type so no throttle, the motor kicks in when pedalling.

What we're the results of the MOSFET and 5v tests?

 

[fwmgaok]

Hi @saneagle the bike hasn't got a throttle. the sensors on this bike are located on the rear wheel near the cassette (they pick up movement on the cassette i think), the bottom bracket has a sensor in it(100% confirmed) and there is a magnet like sensor attached on the bottom bracket shell which picks up the rotation from the sensors in the bottom bracket to send to the controller. Now I am not sure if i can still use your instructions, which reference to using/turning the throttle, to run the tests despite the bike/motor being a pedal assisted /without throttle type

 

[saneagle]

Hi @saneagle the bike hasn't got a throttle. the sensors on this bike are located on the rear wheel near the cassette (they pick up movement on the cassette i think), the bottom bracket has a sensor in it(100% confirmed) and there is a magnet like sensor attached on the bottom bracket shell which picks up the rotation from the sensors in the bottom bracket to send to the controller. Now I am not sure if i can still use your instructions, which reference to using/turning the throttle, to run the tests despite the bike/motor being a pedal assisted /without throttle type

You don't need a throttle to do the tests detailed as 2 and 6 above. If you won't do the tests, I can't help you.

 

[fwmgaok]

Hi @saneagle I was about to go ahead and start the tests as you had advised but luckily a very similar, slightly older version I think, Giant twist lite was donated recently to the charity I support and work at occasionally as an assistant bike mechanic so I borrowed the front wheel with the motor to test on my twist lite and it worked.

So I am guessing this eliminates any problem with the battery, control modules or connectivity and as the first bike mechanic I checked with who had said the fault is with the 36 volt motor seems to be the case.

Question now is where do I start with the faulty motor. So far Giant have replied saying the support for these models have stopped. I checked with the nearest Giant dealer and they are not able to get any documents or guides as well.