Assistance Not Cutting Out On Kalkhoff - Any Ideas ? ?

[cyclefan]

Hi Guys,

I have a Kalkhoff Agattu Impulse HS8. I love the bike but just developed a niggle and wondered if anyone had any ideas what might be going on - I'm hoping it's something simple !

Pedal assist is working fine until I ease off on the pedaling and I can feel it pushing my legs round and carrying on providing assistance ! It does this for about 10 seconds or so or until I apply the brakes. The effect is most pronounced when easing off from higher speeds ! I've had the rear wheel off and on again but that hasn't made any difference. If anybody has any ideas it would be a great help.

Cheers,


Steve.

 

[103Alex1]

Hi Guys,

I have a Kalkhoff Agattu Impulse HS8. I love the bike but just developed a niggle and wondered if anyone had any ideas what might be going on - I'm hoping it's something simple !

Pedal assist is working fine until I ease off on the pedaling and I can feel it pushing my legs round and carrying on providing assistance ! It does this for about 10 seconds or so or until I apply the brakes. The effect is most pronounced when easing off from higher speeds ! I've had the rear wheel off and on again but that hasn't made any difference. If anybody has any ideas it would be a great help.

Cheers,


Steve.

That's an odd one - there's no diagnostic flowchart I can see in the service manual for what you've reported. Sounds almost like the torque sensor is being over-ridden and the motor is running on - but the brake cutoff is obviously working.

You could try checking the cable connections coming out of the drive unit and entering back of the display (if you have one).

Other than that it's probably back to dealer. Is it under warranty still ?

 

[cyclefan]

Hi Alex. Thanks for your reply. The bike is still under warranty. It recently had the rear sprocket replaced as the other one sheared off. Ran fine for a couple of days and then this. I'm not the most technically minded but I'm completely stumped !! It doesn't have a display.

 

[cyclefan]

Just to add previously I recall you could backpedal and the assistance would stop, now once the assistance has kicked in I can't back pedal as I meet resistance and it just keeps driving me forward for a time.

 

[103Alex1]

Hi Alex. Thanks for your reply. The bike is still under warranty. It recently had the rear sprocket replaced as the other one sheared off. Ran fine for a couple of days and then this. I'm not the most technically minded but I'm completely stumped !! It doesn't have a display.

I really don't know then. If you got it from 50Cycles just ring Matt and ask him what's up. It's easier than messing about trying to work it out yourself. Was the sprocket the same size as the one which broke ?

There'll either be a fix for it you can do easily or it'll likely need drive or sensors replacing which will be back to dealer. It sounds like an electronic issue tbh. A motor shouldn't be pushing the pedals round without you leading the dance.

 

[flecc]

The internal freewheel on the pedalshaft which separates the chainwheel drive from the cranks and pedalshaft is jammed. This results in any motor run-on forcing the pedals around and probably in turn also makes the motor drive carry on since the unit fools itself that you are still pedalling.

A somewhat similar problem used to occur at times on the original Panasonic crank drive unit but in that case due to a differently placed freewheel.

As yours is the Kalkhoff Impulse unit you will have to return the bike to the supplier for repair or unit replacement.

 

[cyclefan]

Ahh, now I understand. I looked to see if there was a problem with the freewheel on the back wheel but thanks for explaining this to me. It makes sense now. So you wouldn't suggest I try and unjam it ? Is it a pretty complicated job ?

 

[flecc]

You'd have to remove the unit from the bike and strip it to attempt that since the freewheel arrangements are usually internal on these crank drive types. Although I'm very familiar with the Panasonic units, I don't know in detail the very different internals of the Impulse so couldn't give any guidance.

As it's under warranty I think it's best referred to the supplier, since any attempt by you could invalidate the warranty and in any case, the internal spares may not be available if any parts are faulty. That for example is the case with the Panasonic unit, no spare internal parts, only repair by replacement.

 

[103Alex1]

As it's under warranty I think it's best referred to the supplier, since any attempt by you could invalidate the warranty and in any case, the internal spares may not be available if any parts are faulty. That for example is the case with the Panasonic unit, no spare internal parts, only repair by replacement.

Definitely. Send it back.

 

[flecc]

Just one thing that can be tried on the Impulse type unit (but not Panasonic) without warranty implications.

Position the r/h crank arm horizontally pointing to the rear. Then wrap a cloth around the lower run of the chain and grip it firmly with your left hand, pulling slightly towards the back against the chainwheel. Then with a hammer or rubber mallet in the right hand, strike the end of the crank arm behind the pedal sharply downwards. If using a hammer, place a plaster or cloth over the end of the crank arm to give some protection to the cosmetics.

If you can then turn the cranks backwards while holding the chain still, that will have freed up the internal freewheel. If it's anything like the Panasonic one this then may never happen again. The freewheel seizure is usually due to a sudden and unusually hard downward jolt on a pedal when the freewheel is in the disengaged state, the force engaging it then jamming it locked into engagement.

 

[jackhandy]

The internal freewheel on the pedalshaft which separates the chainwheel drive from the cranks and pedalshaft is jammed. This results in any motor run-on forcing the pedals around and probably in turn also makes the motor drive carry on since the unit fools itself that you are still .

That must make for Interesting Times

We needed to assure a few nervous ladies (mostly) that the drive would cease immediately they stopped pedalling or touched a brake, when running the test-rides at Eden:

If one of 'em had shot orf into the flowerbeds we'd have had some explaining to do

 

[flecc]

That must make for Interesting Times

We needed to assure a few nervous ladies (mostly) that the drive would cease immediately they stopped pedalling or touched a brake, when running the test-rides at Eden:

If one of 'em had shot orf into the flowerbeds we'd have had some explaining to do

Yes, this is the snag with the crank drives that drive through the chainwheel which have two freewheels (rear wheel and chainwheel). Although the three freewheel Panasonic unit e-bike systems suffer a unit freewheel jam sometimes, it's in the separate motor drive sprocket's freewheel so cannot suffer self-actuated drive continuation.

By the way, touching a brake won't work on most European e-bikes, they rely on the pedelec cutout so don't have brake cutouts.
.

 

[jackhandy]

By the way, touching a brake won't work on most European e-bikes, they rely on the pedelec cutout so don't have brake cutouts.
.

SHH! Don't tell 'em we didn't know what we were talking about

 

[cyclefan]

Just a quick update. Went out for a ride at the weekend and the freewheel began working again following some hard pedalling on a steep incline, then froze up again some time later following another incline ! Will try flecc's idea but looks like it's going back. Thanks again for the advice.