dynamo drive sealing

lindie

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good afternoon. was wondering if someone might post a photo of part no et164 or possibly the item in situ in their primary housing please. i'm running out of other oil leaks and wouldn't mind eradicating this one as well. the oil slinger is there but the oil going through my dynamo is a concern. thanks for your time, glen.
 

John Cone

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Is the oil actually going into the dynamo or do you mean the oil is escaping betwwen the the primary case and the dynamo? I think most people will agree that silicon is the answer. Remove the dynamo and cleam up the surfaces of the dynamo and the primary case. Before refitting the dynamo you need to apply a large bead of silicon sealant around the endplate of the dynamo, and while it's still soft refit the dynamo and adjust the sprocket so that the backlash is correct and also that the sprocket is in the center of the middle link of the primary chain. Refit the dynamo saddle and tighten making sure your adjustments have not altered and the silicon should of been squeezed out of the joint. It's worth fitting a sealed bearing in the drive endplate of the dynamo while it's off. There are some differences in the way that the primary cases were machined around the dynamo hole depending on the model or year, mines a "D" and the method i used works for me.
 

lindie

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hi john. the dynamo is filling up beautifully. it was chockers with the stuff when i first pulled it off last year. found the same last weekend when i stripped her down for the jg regulator. my parts book shows what appears to be the other component of the oil slinger arrangement but it ain't in there. know thy beast gives a sectioned view of it as well but i'm interested to see what she looks like in the flesh if i can. it's likely not a total cure but better than missing parts till i sort out an alternative.

the bearings in the dynamo are 200 miles old and i'd rather not hoik them as it was a 60 buck part and took three days to procure. i'll live happily with some runoff but the current situation is more a bucket under an umbrella with a hole cut out of it.

cheers, glen.
 
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John Cone

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Hi Glen

Just had a butchers at Know thhy Beast, did mean that the tapered adaptor PD32 is missing or the oil ring ET164. this is what i meant when i said some cases are different. On a "D" it does not have PD32 because the casting had not been machined out to a taper it had been left flat.
 

ogrilp400

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G'day Glenn,
ET164 is a pressed tin affair. A washer with a spigot on it or a spigot with a flange on it how ever you want to call it. Not sure that it does too much other than present a flat face up against the the oil slinger. I Araldited mine in about 31 years ago and it has been there getting a free ride around the country ever since. As for PD 32, I have never ever seen one. Its a real belts and braces affair in there but there is room literally for a sealing arrangement that does seal. I had a Lucas E3L with a sealed drive end bearing on the Norvin for most of the past. That fixed oil getting into the generator. Between the generator and the back of the PD I machined up a 1/8th thick walled tube about 1/2" long. This pressed onto the shallow spigot on the Lucas generator. I then cut a 1/8" thick neoprene cork penny washer that is sandwiched between the tube and the back of the PD. Liberally coat in silastic and push the generator hard over against the back of the PD. This seals it up.
Now it has been a very long time since I have seen a Miller generator but I seem to remember that the Miller has a rounded projection, housing the bearing. Could a similar thick walled tube be machined up to be sandwiched between the the generator and the PD? Perhaps then some sort of seal could be run in this tube to keep the oil out of the generator?
I am surprised the the generator bearing cost so much. I think it is the same size as the Lucas bearing and they came as a sealed bearing and certain didn't cost that much. Something in the order of 5 to 10 dollars.


Phelps.
 

lindie

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Non-VOC Member
G'day Glenn,
.
Now it has been a very long time since I have seen a Miller generator but I seem to remember that the Miller has a rounded projection, housing the bearing.


I think it is the same size as the Lucas bearing.
Phelps.


i think inadvertently you might have just solved something i've been puzzling over for a year or so.
 
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lindie

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Non-VOC Member
thankyou phelps. i think i'll put an et164 on order and look into how best to seal the dynamo itself as well.

does the 3.5 inch D9S miller run a felt around the threaded bearing retainer collar and trapped on the outside of the housing by the PD19 washer?

my spares 3 and a half has a depression cast into the drive end plate on the outside edge that looks like it may hold such a felt as i found in the inside of the 3 inch D6 type housing. that might end up being half my cure as there was never one there before, and i wasn't aware there was to be one.

thanks for any advice on this as i've mainly gone off of what came with the bike wherever there weren't clear pictures or drawings to go by.
 

Len Matthews

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A comment if I may concerning sealing the dynamo against the back of the sprocket housing. Oil loss from here is usually due to excess oil in the primary chaincase. It's well known that most Twins have a tendancy for oil to pass through the drive-side main bearings necessitating the need to drain off the surplus via the level screw.If you seal the dynamo in the way some have described you will prevent the primary chaincase from breathing so any pressure build up will be forced into the dynamo. (Or into the gearbox, won't it Hugo Myatt?!) The felt ring in a Miller dyno won't stop much, far better to use sealed armature bearings which are readily available from bearing stockists.
 
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