Thanks John..:blush: ...Ian

email (option): ian@wright52.plus.com

Yes I thought it was probably wear in the case. I have managed to measure it and it appears to have worn fairly round. I have ordered a seal 2mm bigger and will gently relieve the hole to make it fit as it is really close.

Tony.

email (option): tony-wilkinson@sky.com

Many years ago I repaired my B33 the way Ron did. It is still working well.

email (option): ian.clare1@virgin.net

Hi Ian,

Thanks for that. So I have a couple of options now without resorting to drastic surgery.

Tony.

email (option): tony-wilkinson@sky.com

Just to be clear. I haven't had to use the JB remedy on my M20 as the standard seal still fits, but I have used loctite to try and avoid any future movement. My recommendation for JB Weld is based on other applications. Ron

email (option): ronpier@talk21.com

I repaired this problem with the engine together and in the bike with silicone gasket compound.

Put the mag back on the bike and set the gear mesh.

Tighten the strap.

Remove the gear.

Put silicone on the seal face and cases and push it in to the recess.

Put the gear back on and tighten the nut while silicone is still wet.

Once gear is back on, don't turn or move the gear at all!!!!! Especially don't back off the gear or the seal will move back away from the cases and you need to start over. Put the gear on in one movement and tighten the nut a little bit.

Have a beer and wait overnight for the silicone to set.

Then time the mag.


I did this to a B32 and it is still working after 20 years with no issues.

As an aside. My M20 worked perfectly with it's rebuilt mag for about 20 years, but suddenly stopped whilst on idle when I was closing the gate in my lane. I spent 1/2 hour trying to restart it by all the usual checks and measures, but arrive late at the rendezvous on a different bike.

There was no spark at the mag and when my guy opened it up, it was full of oil.....Culprit was a rock hard oil seal. Ron

email (option): ronpier@talk21.com

I have to repair my crankcases as someone managed to crack them around the magneto seal housing. I expect I’ll just weld them up and bring them back to standard. I have some photos of goldstar crankcase drawings and hopefully the position is the same. I want to make a tooling plate to allow for many other repairs. After getting that far, it wouldn’t take much to make a jig plate that could be shared around for finding the centre.

Mark

email (option): pes.sales@btconnect.com

In my case :) the hole was oval and i used the JB weld method thats still holding buy i had the problem of finding centre in order to place my seal, A plate would solve this, and after the plate was made all that would be needed to share would be the dimensions of it for those of us in far flung places like western Canada

email (option): taybrig@shaw.ca

Kevin, hence my suggestion of clamping the mag with it's pinion in place before the JB sets. It will naturally be in the right location. Ron

email (option): ronpier@talk21.com

I might be offering more than I can deliver. I was hoping that a simple jig plate could not only be used to find the hole center, but also assist in check the magneto height and ensure the correct mesh with the gears.
Treat this as a fantasy until I manage to do it.

Just a side note, if aluminium has been repaired with any kind of epoxy it's incredibly hard to weld afterwards.

email (option): pes.sales@btconnect.com

I should have checked the size first!
Enlisting the help of Anita I asked her to machine my welded crankcases.
Unfortunately, I hadn't checked the size of the hole for the oil seal.
Yes it was oversize and would not clean up.

I should have done this in the first place.
Casting flipped over and machined for a repair insert.
I'm just hoping that the BSA hole center matches the one the magneto was lined up to.
If it doesn't work options include making an eccentric repair insert or making an over or undersized magneto gear.



Mark

email (option): pes.sales@btconnect.com

I've made this up a few years ago, it worked o.k.
Not BSA but in general the same, see pics.

email (option): info@wetblast.nl

Looks good Vincent,

Mark

email (option): pes.sales@btconnect.com

I did pretty much the same as Bruce. In my case the case was almost worn through. Never thought much about it, just packed silicon sealant round the felt washer and let it set. It's never leaked since. Folks overcomplicate things.

email (option): jeremy@clogmaker.co.uk

['Folks overcomplicate things...']

Not really, remachining the crankcase is a permanent and accurate engineered solution that makes any future oil seal change a straight forward job...

It's a different but better solution than various forms of 'glue' which IMO are only a temporary bodge to get you out of trouble until the correct solution is applied...I try to start from the point of 'best practice' wherever possible as there is a tendency to end up bodging everything if the easiest route is always followed...Ian

email (option): ian@wright52.plus.com

Hi John,

I the recess tor the bearing still seems to be round, so I'm guessing I just have the incorrect seal sizes. I've ordered a larger seal and hope this will fix the issue.

Glenn

email (option): Glenn_mullan@postmaster.co.uk

It rather depends how much time and money one wants to chuck at the problem. My mag has been off a couple of times since I bodged it seven or so years ago and I haven't had to do anything further.

email (option): jeremy@clogmaker.co.uk

Some of us simply.like. Proper engineering solutions and hate the idea that next time a routine task has to be undertaken, previous botches will mean a long term "Vehicle Off Road".

Surely the point of this hobby is to do it to the best of our ability ? If not, and we simply like gluing things then collages must be the way forward :grinning:

In terms of bodges this is a very minor and reversible one. If it fails to stop a leak one just tries something far more expensive and time consuming. The bodge itself leaves no mark on the cases and doesn't involve any moving parts. By all means spend time and money if you have both to spare. I just use my M21 as transport in the summer months. In the winter it gently decomposes under a sheet next to my workshop. It's never been 'restored' and to call it's rusty condition patina is rather stretching the term. Using the gearbox is rather like stirring porridge, it needs a gentle touch to avoid neutrals, having been abused for decades with a previous sidecar.
However it runs LEDs, a Triumph clutch, a top quality English made electronic regulator [none of that Far East garbage] & has had a complete engine rebuild of the internals. I expect it to happily make another 30 years, far more than I have left.
When I was at school and college the charm of the M21 was that it would run and keep running when pretty worn out; and worn out bikes were all I could afford. They didn't need constant attention and parts to keep them on the road. After a gap of some forty years I'm on my third one, so I suppose my attitude is atypical on this site. When I ride it I'm 20 again, just as long as I don't see my reflection....

email (option): jeremy@clogmaker.co.uk