Dynamo armature replacement

56G80S · Post by **56G80S** » Fri Sep 14, 2007 11:24 pm

Those who read my Woolwich trip exploits will realise that I need to do something about the dynamo.

I only need a replacement armature (and a reg) but can't get the commutator end of the armature out of the bearing. The bearings are relatively new, the field coil is fine, the brushes are also almost new.

I'm wary of falling into my usual trap of applying too much force as the zinc casing won't take it, or too much heat.

I was thinking of a heat gun or even immersion in boiling water and a gentle go with a puller.

Advice welcome.

Nobody's mentioned the Arrow and Hawk that were at Woolwich. G15 Roy sent me a CD, I forgot my camera, included in the pics is one with me in the background leering at the V4 as it went past: And his offer wasn't the only one. There's good people in the Club.

Johnny B

wilko · Post by **wilko** » Sat Sep 15, 2007 3:05 am

you're right jonny they are a dog to get off! i think heating it might only heat the bearing and the shaft but it might help, and i've never had a puller thin enough to get behind the bearing. they do exist of course but i've always needed one on a sunday so resorted to heavy handedness. douglas

bag-o-nails · Post by **bag-o-nails** » Tue Sep 18, 2007 11:34 am

I Think You Need to have a word with
The magneto & dynamo man
featured in classic bike April 2007

Stuart Tower tel: 0208 397 6599
Stuarttower@blueyonder.co.uk
cheers
b-o-n

wilko · Post by **wilko** » Wed Sep 19, 2007 5:19 am

sorry johnny i thought you meant getting the bearing off the shaft which is a dog to get off. i've never had trouble getting the bearing out of the housing by adding some heat. douglas

56G80S · Post by **56G80S** » Wed Sep 19, 2007 1:56 pm

Thanks for the comments. Have now successfully dismantled the dynamo, except for the drive end. Have removed the "keyhole" shaped retaining plate for the bearing, although one of the 3 screws was a mess and I was lucky to get it to shift - need some new ones for re-assembly. Removed the plate to gain better access to the circular "nut" that screws onto the shaft.

I guess this needs a peg spanner, but the slots are in poor condition, so may need to adopt other measures.

Also a recessed steel washer with a material ring fell off the commutator end. Unfortunately, I didn't see which way round they were, any comments welcome, particularly on

Source for three new screws for the plate,
Correct assembly of the washer and correct nature of material ring,
Potential source for the circular nut!

Home battery charging still means I was able to enjoy the 36 miles to work yesterday morning - very cold over the tops, but bright, sunny and great!

Johnny B
Edited by - 56G80S on 19 Sep 2007 12:56:55 PM

bag-o-nails · Post by **bag-o-nails** » Wed Sep 19, 2007 8:32 pm

The Answer to your supplier of parts is above you he only does mag's and dyno's
Cheers
b-o-n

56G80S · Post by **56G80S** » Thu Sep 20, 2007 10:43 pm

Got an undeliverable for stuart Tower.

I do have a interesting point, though. Having looked at the Lucas service sheet (thanks Biscuit) I'm puzzled by the stamping on my dynamo - E3NL.

This is clearly a factory stamping. The alignment, stamp face etc all suggest it wasn't added later.

Leaves me unsure whether it's 45 or 60 watt for a start. I'll measure the armature length and that should tell me as the E3N is supposed to be shorter than the others.

Johnny B

bag-o-nails · Post by **bag-o-nails** » Fri Sep 21, 2007 1:00 am

Sorry Johnny
I missed a dot. it should read
Stuart.tower@blueyonder.co.uk

I must go and get my eyes tested
time for spec's, me think's
Cheers
b-o-n

56G80S · Post by **56G80S** » Wed Sep 26, 2007 9:44 pm

Now have the armature bare. Very small cold chisel and plumbers vice meant I got the ring off with little trouble and the bearing pulled off with a heavy two leg puller.

Armature measures aprox 6 and half inches (166.5 mm) and so it is the E3N. JSL has them listed and they're cheaper than elswhere - Classic Solutions want £55.32 plus VAT but as they're in Durham I could pop round and get it at lunchtime from work and avoid postage costs. Thing is, I'd guess that the JSL more likely to be right and receptive to sorting out any problems. AMC Classic Spares have them listed as new, not rewound but I don't know if that means NOS, which would be tempting. Any views?

I'd even thought of getting a later one to have 60 instead of 45 watts. But plan to stick with current (!) one and 6 volts, electronic reg. get the LED rear light from Goffy (present one's lens stuck together anyway after shed misjudgement and one of long bolts fell off after Woolwich run). I should then be able to run the 35/35 watt halogen bulb and halogen pilot light for a daytime light and still have power to spare. Any views on this?

I'm an optimist, but clearly the setup I'd run before (35/35 headlight and all the usual other bits) was too much for the dynamo - it should've been 25/25 headlight all along.

Although the bearings are "new" having done only 3,000 miles I wonder if I should do them as well - they're not expensive after all.

B-O-N, still haven't got through to Stuart Tower, but will try again.

Johnny B

Biscuit · Post by **Biscuit** » Wed Sep 26, 2007 10:12 pm

The dynamo can only charge the battery, the electrical load means nothing to the dynamo, it's the battery that will suffer. True the dynamo will spend longer keeping the battery charged, but that should be well within it's capacity.

The JSL are new, not old stock. I had a duff one and they changed it with no hesitation.