Sealing Norton Atlas primary chain cover?.

[Keithmac]

Hello everyone, I believe we have a fre on here who are into the old British bikes.

I took a job on for a good customer of ours a while back, usual story, bought a bike off ebay..

He wanted carbs rebuilding which I did using new "stay up" float kits etc.

Bike was a nightmare to start and keep running. Good spark with plugs out of cylinders which was odd as it sounded ignition related.

Anyway, I've ended up fitting a Boyer Bransden ignition and pickups and it runs like a dream now. (Removing the Magneto is not everyone's cup of tea but it's made a usable bike).

So last part of the puzzle is sealing the primary chain case.

I'm reluctant to blather it all in Three Bond as it may need to come off again but I just can't see how it will ever be oil tight?. Any tips would be welcome at this point.

I have heard there is a dry belt conversion but that sounds expensive!.

Just interested how other people go about sealing these up (it had no oil in it when I removed the cover).
Cheers all.

 

[Popcorn]

Fit a belt conversion

whoops said that before reading your post fully

 

[OJCar]

Get the sealing faces of the inner and outer chaincases smooth and flat.
A PO will have swung on the clamping nut and distorted the cases so
best to get them both off the bike so you can work away at them, seeing the bits you can't when they're on the bike.
Behind the clutch there is a sort of sliding arrangement that you need to check is sealing.
You may need to drill out the spotwelds to dismantle the sliding discs bit, rebuild with new discs (part no. 06.0769)
https://andover-norton.co.uk/en/shop-details-2/15409/inner-chaincase-sealing-disc
New seal on the clamp/footrest tube (part no. 04.2055)

https://andover-norton.co.uk/en/shop-drawing/903/primary-chaincase

New Sealing band (part no. 06.7267).
I use red rubber grease on the sealing band not gasket goo.

Some people run ATF in the primary drive rather than oil, I don't think it gives an improvement and it leaks more.

HTH

 

[dave h 2]

Lots of talk about bent taper screws on the internet, strikes me that if someone drops it on the lefthand side the footpeg causes the leak.

 

[OJCar]

BTW

Make sure it can breathe OK once it is sealed.

If it was your own bike I'd suggest changing the Atlas pressed tin Primary Drive cases for the Commando Alloy cases.
Its not a bolt-on fix, so I don't think you will want to get involved in that for a customer's bike.

 

[Keithmac]

Thanks for all the replies, much appreciated.

The outer tin cover is not in great shape so will take a lot of fettling to get a good seal.

I might get him in for a chat about the options but if it were mine I'd be doing a dry belt conversion and call it a day.

Just been mounting the coils properly this morning and tidying the wiring.

 

[Keithmac]

There doesn't seem any mention of using different clutch plates with the dry belt so I presume the originals are ok ran dry?.

 

[OJCar]

Clutch plates can be run dry or wet.
The oil is there for the primary chain.

On the race bikes we used to run the P Drive open to air and just use some spray chain lube on the chain.

 

[Keithmac]

Clutch plates can be run dry or wet.
The oil is there for the primary chain.

On the race bikes we used to run the P Drive open to air and just use some spray chain lube on the chain.

I did think of that as his 3rd option, lube the primary chain, there is an access hole innthe cover that could be used for the job.

Looking at RGM dry belt kits I believe they come with new clutch plates (look sintered metal friction coating?).

Will see what he says tomorrow.

Thanks again for the help.

 

[redlig]

If you intend to run with oil in the case and all else fails then possibly concocting a breather to atmosphere will reduce the internal pressure and reduce the reason for the oil escapage.

 

[brightspark]

those cases are a dead loss for leaking even with a new gasket i just keep my chain well lubricated with chain spray through the cap on the outer case

 

[Keithmac]

those cases are a dead loss for leaking even with a new gasket i just keep my chain well lubricated with chain spray through the cap on the outer case

That's what I thought when I took it to bits. It had already been blathered in sealant and had lost all it's oil.

The later alloy cases look like the have at least half a chance of sealing but these tin ones not so much!.

Does the chain lube affect the clutch at all?, that was my only concern with that option.

Just glad it runs well now and engine sounds great so not far off!.

Shame he got legged into it, see it far too often with ebay purchases unfortunately.

 

[OJCar]

Does the chain lube affect the clutch at all?,

No.

 

[brightspark]

as above no just a quick spray on chain before every outing

 

[oldbikedavey]

Might be worth fitting a drip-oiler ?

 

[dave h 2]

If you intend to run with oil in the case and all else fails then possibly concocting a breather to atmosphere will reduce the internal pressure and reduce the reason for the oil escapage.

Speaking as someone who used to have oil sprayed on his knee by a Triumph pushrod tube. That is a very good idea.

 

[Keithmac]

The customer has gone for chain lube route, best result all round really.

He was chuffed to bits to hear it running so well, nice to see!.

Thanks again for all the replies, much appreciated.