Clacking noise - Kalkhoff Impulse 2 motor

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Tomtomato

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Apr 28, 2015
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He reported that by back pedalling momentarily, the noise went away.
This describes exactly the issue I had. The clicking noise was going away when back pedaling, at least initially, but then this didn't work and clicking noise was almost always there.
 
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Tomtomato

Esteemed Pedelecer
Apr 28, 2015
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Tomtomato, how quiet is your new motor, do you get a low level hum/whirring noise or is it completely silent?
New motor is very quiet. To be honest, I can't hear it most of the time (given speed noise, wind etc). I have probably done around 300 miles so far with the new motor, and I haven't heard any special noise once, in any assistance mode.

Motor was replaced under warranty. As the London shop was not well staffed for a few weeks (due to recruitment pending), the 50 Cycles management team got involved, they shipped the bike from the London shop back to the HQ to get it fixed (rather than having the bike staying in the shop for too long), and then shipped the bike back to me directly by courier (a large box!) a few days later, at their own cost, which is commendable.

Unfortunately, the new wiring around the motor didn't look too waterproof (visible connectors etc.) and the computer cable was damaged/exposed in the process (still working, but outer wire protection pulled).

The bike went back to the London shop (now staffed), and all has been fixed now. Computer and handlebar control had to be entirely replaced by new ones (due to the design), which is not a small task, but it was done while I waited, so the bike was not off the road.

While it took several attempts to resolve fully the issues, everything is now fine, and the bike is great.

The old motor was initially very quiet too, apart from the clicking noise, which became more frequent progressively, under all assistance modes. Also, I could feel some vibrations through the pedals...

An easy way to know if the noise is coming from the motor or something else (pedals, gears etc) is just to switch off the motor/assistance and keep pedaling at the same pace.

BTW, I believe the motor is not serviceable, so the full unit has to be replaced in case of a fault, and Kalkhoff don't sell it as a part directly to end-users, probably to protect their intellectual property and prevent retrofitting (Bosch does the same with its motors).

Despite the fault, I think the Pro Connect 10 is a great bike, with a very transparent/progressive assistance, good build quality and components, and I don't think there are many competitors on the market, with such large battery and similar components.
 
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nightrider

Pedelecer
Sep 11, 2014
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Keep touching that piece of wood;). It would be good for all Impulse 2 motor Kalkhoff owners to keep in touch and report any motor problems here, so we can get a measure on how common the problem is becoming. I think I count about 5 so far, and Tlllson's report that a replacement motor is showing tell tale signs of incipient failure is a concern.
I had the motor replaced on my endeavour s10 last year under warranty similar issues, with increased reports certainly becoming a bit of a concern.
 
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nemesis

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Mar 14, 2011
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Mine went bang this morning with a loud clacking noise as described followed by the cranks feeling like the motor was seizing up inside,2015 speed 2 impulse motor,now for all the faffing about getting a new motor but still a great bike even so, the reliability seems a bit hit and miss.
 

oriteroom

Esteemed Pedelecer
Jul 13, 2008
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Mine went bang this morning with a loud clacking noise as described followed by the cranks feeling like the motor was seizing up inside,2015 speed 2 impulse motor,now for all the faffing about getting a new motor but still a great bike even so, the reliability seems a bit hit and miss.
Sorry to hear that Nemesis. Please keep us informed on how you get on with the replacement. Osho also has problems with a Tasman motor and is returning it to Bristol at weekend. As you say, it's all the faffing around. Starting to ride wife's Tasman with some trepidation.
 

Roger R

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Jul 6, 2015
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Check out my latest video with comment from Peter. Be interested in views on this.
 

lordvincent

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Jan 23, 2015
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This describes exactly the issue I had. The clicking noise was going away when back pedaling, at least initially, but then this didn't work and clicking noise was almost always there.
Did the noise start as a single occasional clack and then progress?
 

Roger R

Pedelecer
Jul 6, 2015
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Did the noise start as a single occasional clack and then progress?
The noise started about a month from new and was actually much worse than the YouTube recordings. It was a consistent clacking in top power uphill. I still have this recording and sent it to 50 cycles. I have contacted them again last week and they are waiting until they have a motor in stock then I'm taking it in. They will then check it out and hopefully replace.
 

Tomtomato

Esteemed Pedelecer
Apr 28, 2015
388
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Did the noise start as a single occasional clack and then progress?
Initially, the motor was very quiet. However, when going on a steep hill with the maximum assistance, I could hear some clacking noise about once per pedal rev., and it would stop once using a lower assistance mode, or pedaling backwards once.

I initially thought it could be the chain going through a lot of torque.

However, the noise then occurred after 30-60 minutes of cycling on the flat with the lower assistance, first occasionally and then continuously.

Basically, the issue was worsening, until it became almost permanent and quite annoying.

For people considering a motor change, do check the rewiring.
When they replaced mine, they left a few cables and connectors quite exposed (no protection or tubing) and visible, so I am not sure the bike electronics would have survived a big splash (e.g. cycling through a water puddle). A remote risk, since the motor is placed quite high, and the cables are on top of it, but this would be annoying.

I ended up removing the battery cradle/motor protection (2 screws and one clip) and putting some self-amalgamating tape over the cables/connectors, to make them a bit more waterproof.
 
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Colin Tate

Pedelecer
Jan 16, 2015
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My Tasman Impulse 2 has also started making a clicking sound, after about 1000 miles. I'm not sure it's the same as the noises recorded here. What I'm experiencing is a momentary snap as I pull away, as if something has slipped. After that everything seems normal and I can pedal normally without any noise. This is an intermittent thing and doesn't happen all the time though it is fairly regular. I'm pretty sure it's not the chain (it's new), but something coming for the pedals or the gears. When I back pedal a fraction then move forward again I also get a clicking but I'm not sure it's related to the snapping sound when I pull away. Interestingly I wasn't aware of this problem until I did get my chain changed. Coincidence?

Usually the snapping sound is fairly minor but once or twice has been quite dramatic as though something was actually breaking. Quite disconcerting, though I haven't been particularly impressed by 50cycles to date. Perhaps I need to persist when them for a solution. In the meantime, any ideas or comments would be grateful.
 
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Tomtomato

Esteemed Pedelecer
Apr 28, 2015
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I'm pretty sure it's not the chain (it's new), but something coming for the pedals or the gears.
I think you need to do a bit more investigation, as you don't seem to be sure if the noise is coming from the front (motor, crank) or the back (gears).

One way to know for sure if it's the motor is to turn it off while you hear the noise, and continue pedaling at the same cadence. If the noise stops straight away, then it's most likely coming from the motor assistance...
 

Colin Tate

Pedelecer
Jan 16, 2015
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I think you need to do a bit more investigation, as you don't seem to be sure if the noise is coming from the front (motor, crank) or the back (gears).

One way to know for sure if it's the motor is to turn it off while you hear the noise, and continue pedaling at the same cadence. If the noise stops straight away, then it's most likely coming from the motor assistance...
Well you're right. But when it only makes a momentary crack when pulling away (and it's only occasionally too) it's very difficult!
 

Tomtomato

Esteemed Pedelecer
Apr 28, 2015
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Sorry, I didn't realise the noise was only happening when pulling away.

My bike did some loud cracking noise too when pulling away, a few times, before the motor was replaced.

There was one incident when I changed the level of assistance while stationary at traffic lights (didn't change the gear), and there was a loud noise as if something had broken when I started pedaling...
 

Colin Tate

Pedelecer
Jan 16, 2015
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I hope that doesn't happen mine. Not sure it will be easy to get it from Scotland down South ... How long did yours take to progress from the first cracking until it got worse?
 

One_Box

Pedelecer
Jul 29, 2014
181
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Leominster
My Tasman Impulse 2 ( now 700 miles ) makes the same whining noise as the problem bikes but not the clicking noises. It is however nowhere near as quiet as the BBS01 motor on my Pashley Parabike conversion.
 

SteveRuss

Esteemed Pedelecer
Feb 12, 2015
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Yes, it's 8 hub gears.
If it's the Alfine hub gear, have you made sure that the two green lines are perfectly lined up when it's set to fourth gear?

Mine used to do exactly the same as what you're describing when pulling away until I got the hang of setting up the gears. There's a fine line between getting it right and getting it wrong. If you've just had your chain changed then it's pretty likely to be your problem.

 
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