The motor is a BMC not a MAC.
OK well I should have sorted this at the weekend
but had other things on, the motor had been making a nasty sound but was still working, albeit sometimes it would spin and other times it would engage, anyway been riding it like this for a week or so and at lunch time I said to the missus, I really must strip the motor tonight and see what wrong with it, I went out of the door and in the first few seconds it went with some style.
There was a nasty gnarling sound and that was it, so I peddled to work and home (that nearly killed me) ha ha and then got the motor apart, this motor is old over 6 years old and has never been touched, has been used every day pretty much and has never had any maintenance, luckily all of the screws came out OK (used to grease them back in the day) which is great as the heads on them are easy to strip. The motor came apart quite easy, see picture below, for an old motor that is kept outside and ridden in all weathers its remarkably clean inside.
It was evident from looking at the gears that they were badly damaged in 1 place only, they looked in really good condition otherwise, my suspicions were the one way bearing, anyway got my old puller out and after a bit of pratting about getting the circlip off I started to pull, my god it was hard work (I found out later why) It wouldnt shift, I had to get a really old pair of pipe grips to hold it whilst I had 2 spanners for leverage trying to pull it off, eventually it came off with a mighty crack, shortly followed by the sound of ball bearings falling about the place.
The one way bearing was mashed, the casing had cracked, the sharp bits of metal had got sucked in to the gears and destroyed them
should have done this at the weekend
oh well, anyway you can see from the photos the bearing is toast, notice apart from the bit where the gears have been damaged the other parts of the gears are in amazing shape, this motor has done 8,000 miles or so at 1.6KW
Here you can see the backside of the one way bearing, its mangled, I am taking the plate in to work tomorrow to see If I can take the top clamp plate off, I have some gears from another motor that are OK and I have found a supplier for the bearings in the UK too
at only 10 pounds its much cheaper than a new clutch.
The reason the clutch assembly was so hard to pull off the motor was the casing of the bearing was driven between the key in the shaft and the clutch, see how the edge of the key has been deformed by the puller as I used all my strength to get it off.
Here is the topside of the clutch, as you can see its very different to the MAC clutch, this is why I would rather try and repair this one than fit a new one.
Here is the super clean windings, as you can see from the nice colour of the windings they are like new!! these motors happily chug along with up to 2KW, most DD motors would be in much worse state for the same performance.
Now before the DD motor lovers rain on my thread, I also love DD motors, my X5 Trek bike is my saviour as this one is going to out of action for a week or so, I will post pictures and details of it going back together, if you are in the UK check these guys out for bearings or sprag clutch bearings.http://tinyurl.com/c7p5chc
I might get a new set of gears, the sun gear in the motor casing is in such good shape, there isnt a mark on it, I think the bearing has been on its way out for a long time now I think about it as there have been strange noised coming from it for a while now. Anyway I am hoping I can repair this motor for pennies, it should be good for another 8000 miles I reckon