Help! Trying to repair Panasonic motor on Raliegh Dover

[Pholcus]

Latest update:
A big thank you to Martin for his kind offer of a dead Panasonic motor so I could swap the bearings over. It arrived this morning. I've so far swapped the complete nylon cog assembly, but the rumbling is still there :-( I'm now wondering whether the rumbling could be caused by a worn chain or drive cog? Maybe the rumbling is actually there all the time and turning the motor on increases the noise so it becomes noticeable. Any thoughts anyone? Probably clutching at straws. I'll swap over the other shaft to see if that makes a difference.

 

[Deleted member 4366]

Without hearing the noise, it's impossible to say.

 

[flecc]

Make sure you eliminate the chain and chain follower/idler as causes. The idler arm can come slightly adrift on these units or even bind sometimes, either causing noise.

If not, then reverse the motor chain sprocket on it's shaft, since that will present the unworn tooth faces to the chain rollers. Slight wear and hooking of that small 9 tooth sprocket can cause noise as the teeth catch on the chain at the release point.
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[Pholcus]

Flecc that's brilliant!! Will try this later today. I am also going to have to give your website a more thorough read.

 

[Pholcus]

Problem solved!!!!!
Turning the drive gear around got rid of the rumbling noise.
I've learned a very important lesson from this: check the simple things first and don't jump to conclusions.
Weird thing is the cog doesn't look worn to the naked eye, but obviously is.
A really big thank you to all who have helped in this. Hope this will help others with this problem.
Now I have a new project, trying to bring Martin's motor back to life, stand by for a new thread!

 

[flecc]

Weird thing is the cog doesn't look worn to the naked eye, but obviously is.

It's the tiny diameter of this 9 tooth sprocket that is potentially a problem. At the chain roller engagement and release points the tooth is turned beyond a right angle to the chain, so the tooth tip catches more easily if there's the slightest trace of hooking.
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