Oil in the mag!

[alanp]

She's not been herself for a while, lack of power/cutting out/misfire at low revs, and the last thing I checked today was the HT pick up condition. Whoops, they're covered in oil!!! Also the earth pick up.
I've noticed a small oil drip from somewhere at the back of the engine casings for a few weeks and couldn't locate the source. I had tightened up the 3 nuts securing the mag. onto the timing case but it didn't make a difference, so kept searching.
I suppose the oil seal at the mag. drive end is kaput.
It was reconditioned a year or so ago so didn't suspect this until I ran out of other candidates.
Hope I can find someone with a new drive end bearing and seal.
Happy days
Alan

[groily]

It's funny Alan, but a new seal in one of mine lasted no time at all either (under a year of regular use). Maybe they don't make them from the same stuff as in days of yore, I dunno. Anyway, for the seal and bearings, insulator washers, and all sundries (if you want brushes and springs etc etc etc), Independent Ignition Supplies, or Dave Lindsley, or or or  . . . will sort you out off the shelf in no time. Might be able to get a bearing cheaper through the likes of Bearing Boys if you need to replace, not sure about that. Best of luck.

[alanp]

Thanks Groily, I'll take it off the bike tomorrow and take it apart to identify bearing and seal sizes and then order from Independent Ignition Supplies. I like the fact that you can order directly from their web site and that they have photos of the bits to aid identification. I hadn't seen that site before. It's now in my Favorites listing.
Cheers
Alan

[chaterlea25]

Hi Alan,
I have found that on several occasions that the bearing comes loose in the housing because an incorrect or badly fitted insulating washer has been used  ????
The insulating washers come in a at least 2 thicknesses, sometimes I have had to cut a special
the oilseal is held in place by the bearing, its hold on the housing is dependant on the insulating washer
normally the bearing is ok, at the drive end its an E18.  E15 at the points end
Wear on the mag shaft can lead to leaks as well
Another issue that can force oil into the mag is crankcase pressure !
When you take off the timing cover check that the rotating breather sleeve is held tightly by the cork washer
if you can rock it with your fingers its probably too loose
to remove the bearings from the housing and shaft a few special tools are needed
Remember to REMOVE the spark gap screws before trying to take out the armature

HTH
John O R

[alanp]

Thanks John for the tips. I've been thinking about passing it over to the local mag guru who rebuilt it last year, but if I do I'll never learn for myself.
What I'll do is take it off, dismantle it a step at a time depending on tools I have to hand and problems discovered.
I can always pass him a pile of bits!!!
When you mentioned the spark gap screws I thought I'd better see if I had any diagrams on the mag. construction rather than go 'gung ho' tearing it apart and lo and behold I've found a K2F overhaul article from the Classic Bike of Sept '08. It all looks ok except for removing the inner race of the bearing at the slip ring end which seems to need an 'Octopus'. There's a picture of it, so I hope my problems are at the drive end and not the slip ring end.
It looks like it's either the Ducati or the Beemer to Paignton Bike Night tonight. My classic gang are quite understanding, there's always one of us in bike trouble.
Alan

[groily]

Unless you find the slip ring is deeply tracked, or unless you want to go right on in and swap the condenser, you'll probably be OK there Alan. And if the slop in the drive end is simply the insulator breaking up per previous comment from John, then you won't have to get the inner race off that end either. The races are really the only hard part in terms of dismantling them, though sometimes an original undisturbed and shellacky slip ring can be a tough one as they're fragile. If you DO have to get the cb end bearing off, you need a way of protecting the brass taper for the cb backplate while using whatever puller - I use a small mating tapered shouldered plug with a centre drilled pimple, which fits exactly over the shaft to protect the extreme end, and over which the inner race can be pulled.
Before pulling it apart, good idea to see what end float there is - it's dealt with unfortunately by shims behind the races if there's too much, or by large brass shims between the contact btreaker end housing and the main body if things are too tight. There are often several of both! If you've only got wobble at the drive end - ie no float to speak of - John's point is all the more likely to be right.
You'll find it's a fiddle to get your new oil seal, insulator and bearing outer race into place. The magnets tend to play havoc. I use a length of threaded non-ferrous rod with all the bits carefully arranged between washers and nuts, to get things started. And to keep the insulator in place - they do come in at least 2 thicknesses from IIS as you'll have seen - I reckon MG's recent tip on using an elastic band to hold the insulator onto the race is brilliant having tried it literally this past weekend - gets it central and removes a lot of hassle.

[alanp]

I've checked the drive end and can feel radial movement of the shaft so carried on with the strip and came to a halt at getting the inner race off. I couldn't detect if it was the bearing worn or a compressed insulator or both. The insulator isn't damaged but could be flattened, but I can't tell.
I've left a message with the local mag. guy to call me.
Alan

[groily]

If the insulator and outer race are still a good fit in the mag body (and didn't just fall out together when the armature was withdrawn, which happens), then could be you're out of luck on the bearing front. Does either race look discoloured or worn or rough where the balls run?
An oft-suggested but slightly brutal old-time recommendation for getting the inner race off that end is to wrap a piece of single strand thick copper wire round the track in the race, put it in a vice with soft jaws, and tap the armature end (with its nut, or better still an acorn nut, in place). Does often work, but can also end up cracking the race if you're too heavy-handed with the squeeze! Have the tee-shirt for both outcomes. More good luck!

[Triton Thrasher]

If the bearing tracks and balls are worn, they will look obviously chewed up.

[trevinoz]

Alan,
             You will get radial play if the bearings have too much end play.
If you have a lathe, machine yourself a race puller.
A piece of round bar of, say, 1-1/2" diameter, machined out to clear the largest race you want to remove, to a depth to clear the drive end spindle.
Drill and tap the opposite end 3/8" and make a bolt with a tapered end to suit.
At the busines end drill and tap 3 holes equi distant in the outer diameter, 3/16" or 5mm, to suit the centre of the race.
Use hex head grub screws or cap screws with a radius ground on the ends.
As Groily said, you will need a plug for the points end and I have found many magnetos with no centre drilled into the drive shaft so I have made a threaded sleeve with a centre to go over the shaft.

  Trev.

[alanp]

Ok lads, this is the latest -
I managed to get the guru to look at the mag and told him that the complete armature, drive end bearing, insulator and oil seal came out in one assembly when I took the contact breaker end casing assembly off. He said this probably was a classic case of insulator damage/compression/loose fit which can cause the oil seal to be less than effective.
The bearing races were mint.
He reassembled the mag with a new seal and used a new .015" thick insulator instead of the .012" fitted.
On the top of the pivot of the pivoting contact arm there should be a small cap which locates the pivoting arm and is held down with the leaf spring. The cap was missing so a new one was fitted.
The mag was then tested on a bench and sparked well from very low revs to 2000.
Hopefully things will now be fine.
Thanks to everyone for their help.
Alan

[groily]

Good and not expensive news then Alan - is very excellent. Hope it works as well at however-many Bar in a hot engine.
If I could just remember to take pix of things that didn't exceed the meagre limit we're allowed (J) I'd put up the inner race extractor I use, which is rather as per Trev's description except that it's a double-ended split-clamp affair, each end being a mirror image of the usual 18/15mm races (ie there are proud sections at midpoint of each part of the clamp to match exactly the ball tracks) and it works with any standard two- or more- legged puller (along with the protective plug mentioned for the taper on the cb end). Being 'bespoke' for these particular races, it's actually probably simpler to use than the chuck pullers also referred to on here, but which are expensive (very) and don't offer easy protection for the cb end. Never saw the Classic Bike 'octopus' but imagine it's similar to the sorts of chuck pullers commercially available.
I reckon there's a market for a proper weapon (as in 'made by a toolmaker' rather than by a lunatic in a shed)  . . . But when I talked to a suitably-informed mate about getting a mould made so I could maybe get a load cast (rather than having to turn the darn things up one at a time and slit them accurately in half which takes (me) ages), my heart went out of it as fast as the £/$/? signs flashed up. Interestingly (or not, of course!) many another mag and dynamo uses the same bearing/s, including funny furrin ones of the epoch.
In fact, with interlocking shells inserted into a standard sort of die-holder, all sorts of sizes of races could be catered for by a simple universal tool  . . .
Dreaming again.