The Kalkhoff Klunk - a problem with my Agattu

[danfoto]

I have a Kalkhoff Agattu bought in January 2012, so I guess it's a "2011" model. It has the 18Ah battery, and it's done around 1600 miles.

A few months ago, I noticed an occasional "clunk" or dull knock whilst riding normally on Low or Medium power, which seemed to be coming from the front end.

Fast forward to now, the noise is getting louder, and it happens more frequently. When I leave home and cycle up the lane, which is slightly uphill, I'll hear it perhaps 6-10 times now in the first 1/4 mile. I'm still not sure if I can actually feel it through the bars or if I'm just imagining that.

The noise is real enough, though, and I'm getting nowhere locating it. All I've proved beyond any doubt is that I don't get the noise when pedalling with the power switched off!

This is driving me nuts. Has anybody please got any suggestions as to how I can trace the source?

ETA - I'm not entirely certain of this, but it seems to go away or at least become less frequent, after the bike's been ridden for a mile or so ...

 

[Deleted member 4366]

A while ago, a couple of forum members had clunks when the chain rode up the drive sprocket. Try lubricating your chain, and see if it makes it better. I think their solution was to change the sprocket, but I can't really remember. Also, try holding the front brake on and pushing the bike backwards and forwards to make sure that you've got no play in the steering head bearings.

 

[flecc]

AS d8veh says, it's very likely to be the chain and motor sprocket problem. Have a look at the first four items on this webpage of my Panasonic support website.

 

[Blew it]

I would also suggest checking the tightness of the unit mounting bolts.

The Panasonic unit is secured to the frame by three large bolts. Occasionally these bolts have worked loose allowing the unit to shift when under power. To gain access to the bolts you will need to remove the left-hand cover. This will expose the nuts on the cap head bolts. If the bolts are loose, you will need to remove the right-hand crank, the chainguard and the chain wheel to gain access to the cap heads. An allen key can reach two of the bolts, but the third bolt is covered by the chainwheel, hence the need for removal.

 

[danfoto]

Cheers, chaps. It's definitely not play in the forks or the steering head bearing, so I'll investigate the chain and motor sprocket as soon as I get the chance and I'll report back.