Lafree motor noise

[Tintaglia]

Hi all,

We have a Lafree that has started to make some motor noise. A new noise has appeared to go with the usual one that the motor makes as you ride. The bike is about four years old but hasn't covered a huge mileage.

The noise is is not that loud, a sort of faint screech. It sounds to me very like the "dry bush" sort of noise other electric motors can make sometimes. (Say, a heater motor on a car).

I'm hoping to find someone who has had this problem or knows if I can remove the outer case of the motor to have a look without bits going everywhere

[flecc]

Yes, have a look here and you'll see the internal details. There are two circlips holding the chainwheel and motor drive sprocket to remove for which you'll need circlip pliers, and then nine bolts which allow the crankcase to be separated. Hold back the shafts and gears to the electric motor side as you do that. There's a handy projection on one side that you can tap to get the sides to part. There are no bushes in the main unit, all ballrace bearings except the needle roller bearing on the pedal crankshaft. It may be the neoprene sealing sides on the bearings that are dry and making the noise, and they can be grease smeared without ill effect.

There are four more bolts holding the motor in place, and pulling that out is restricted by the cables and a sensor circuit board, a bit fiddly to get back together. The edge of one motor bearing can be seen and a touch of oil onto that if it's the offender might help. I don't think it's likely to be the problem though.

[allotmenteer]

Could the noise be due to a broken hall effect sensor wire?

From the teamhybrid.co.uk website:

WORD OF CAUTION: the Hall Effect Sensor wires are thin, delicate wires that can be broken. The most common reason these wires get broken is because the nuts, which secure the hub motor/wheel on the front forks are not sufficiently tightened. If the nuts are loose, there is a possibility that the motor will spin within the forks, wrapping the cable into a ball, and severing the tiny Hall Effects Sensor wires. In many cases, you cannot visually see that the Hall Effects Sensor wires are broken. When the Hall Effects Wires are severed, the motor will not fire properly, i.e., the motor will vibrate or "chatter", in much the same way that an automobile engine will run badly when one of it's cyclinders is not firing. Many people mistake the "chattering" for a bad wheel-center bearing, when it is really severed Hall Effects Sensor wires.

Apologies if this is not relevant to the lafree motor.

Paul

[flecc]

Yes, the Lafree is different Paul. It's three Hall sensors are external to the motor as seen below on their board and both are part of a central chain drive power unit. That Team Hybrid info mainly concerns kit motors like their Crystalite. Most production bikes have adequate anti-rotation measures, such as the independently secured torque plate on the Torq's motor.

[Tintaglia]

Thanks for your excellent replies flec & allotmenteer! Exactly what I was after. I'm obviously wrong with the bush noise theory then. I can see now that the load on a bike motor makes a ball race or needle roller bearing a better thing and given the quality of the Lafree all round I can see why they've used those.

Funnily enough, I think there might actually be a problem with the crank sensing because if you lightly press the pedal and then take your foot off it, it leaps back in a way I'm sure it didn't before and I think there is a longer delay in the motor cutting out as you stop pedalling since this slight noise started.

I can't really see how it's connected, but it did get the world's worst soaking when we went to look at the electric bikes at the enjoyable Presteigne show the other day.

Interesting to hear the Lafree uses a hall effect sensor, familiar to me in the motor trade in distributors (a rare thing thing these days). Anyway, I prefer to dicuss anything before I dismantle it so anything anyone can add is welcome.

[flecc]

It could be something related to the pedelec sensor drum area then, judging from your descriptions. In the picture below you'll see the edge of the pedal crank pawl area, and behind it a white connector. This isn't unpluggable but connects directly into the pedelec sensor drum. Once you've removed the cranks and separated the crankcase halves, you can unplug the sensor leads at the mainboard and completely withdraw the pedal crankshaft from the left casing. Then you'll see the pressed steel sensor drum.

There are circlips at each end securing all the components in that area, so they can be removed to see if anything is adrift or otherwise faulty. It could even be a problem with the freewheel pawls. Make sure you note the order of everything and where the shims belong as the placements are probably critical.

Let me know if you find a broken part that needs replacement, since Giant don't supply individual parts, and I may be able to help out.

[allotmenteer]

Originally Posted by Tintaglia

Hi all,

We have a Lafree that has started to make some motor noise. A new noise has appeared to go with the usual one that the motor makes as you ride.

The noise is is not that loud, a sort of faint screech. It sounds to me very like the "dry bush" sort of noise other electric motors can make sometimes. (Say, a heater motor on a car).

Before taking things apart, are you sure it is the motor? I've found a webpage about curing bicycle noises , perhaps it may help.

Bicycle Noises, Clicks, Ticks, Repair

You never know!

Yesterday I too had an annoying noise coming from the back wheel which I thought might be the motor but when I got home I checked and I had 3 loose spokes which I tightened. Coming in this morning the noise had reduced greatly. I think I may still have one or two still loose which I'll check at lunchtime.

[Tintaglia]

Thank you all for your patient replies, having sat up until 2.30 this morning fascinatedly reading through this fantastic forum I see that all the information was already available Incidentally, Flecc, we hail from your part of the world, having lived for 15 years in Warlingham, my wife's short but hilly daily commute to Caterham being the main reason for our first electric bike purchase (an Ecoped with a 36V Schachner front wheel hub drive and Ni-cad battery). We "semi-retired" to Cornwall four years ago but I still work regularly around Warlingham/Caterham. We'll do a proper introduction in the appropriate place "dreckly"

I'm fairly sure the noise is on the motor because it's silent when you stop pedalling, or pedal with the motor switched off. Could anyone with a Lafree check for me if pedals will ping back hard enough to knock you on the ankle if pressed and then let go? (I know, of course, that if you are in the habit of resting the weight of your foot on the pedals at light etc the motor will attempt to drive but I've never noticed this other effect).

[flecc]

I cycle to Warlingham quite frequently, so very local to your old haunts.

I don't get that kickback on my lafree, nor ever have done. It seems that it may be something to do with the motor or gears, though it could equally be an electronic fault. The placement of the Hall sensors is asymetric and I think that delay lines may be incorporated in the mainboard.

An out of synch early current feed could do something odd like that you're experiencing, and another possibility is the Hall sensor board adrift from it's mountings. It sits on two plastic posts against the motor wall with just rubber washers pushed onto the ends of the posts to secure it. Since they tend to get grease on them, they could have come adrift. (My photo shows the board completely away from the motor and against the crankcase side.)

You can see that board and position if you undo the four motor mounting bolts and prise the motor outwards. You'll find it difficult to move it far out without pulling the board off it's mounting though (short wires), so have a look as soon as you have a gap to peer through, maybe with a torch. Getting things back into place is a remote screwdriver job through the gap, very fiddly.
.

[Tintaglia]

Thanks for that flecc. Seeing your description of the internals I think the Hall sensor board sounds a really good possibility. I'd completely forgotten that the bike fell over recently and we're not quite sure, but it seems that these problems started around that time. I'm hoping to look at it over the weekend. I have to get hold of a crank puller first. (Unless by some miracle a similar looking rotor puller I have for a 1973 Yamaha motorcycle happens to fit!)

The bike noises link is handy allotmenteer. We'll definately be keeping a copy.