Primary Oil Leak found

olympus · Jul 22, 2025

Hi All, after many repeated attempts to cure the ongoing chain case oil leak, i have, i think finally found the problem
Up to now all i have done to check for a leak is the pull down the prop stand and wipe my finger along the joint only to find a wet finger.
But today i pulled down the stand and physically looked from underneath...... no leaking joint but a 50mm bead of ATF oil 10mm in from the "O" ring
I believe i have a porous Alton inner chain case.
I have tried to call Alton this afternoon without success, so i have written an e-mail with all the attached photos...... watch this space

seattle##gs · Jul 22, 2025

I thought the Alton runs dry

1973x75 · Jul 22, 2025

I had a drip like that on my stock chain case. I used a mirror and a flash light to check underneath, and found it was coming from the new felt seal I had installed. It stopped after a couple hundred miles, inexplicably, but I guess maybe it centered itself. No, I did not let it all leak out, it has a fresh 7 oz of atf.

baz · Jul 22, 2025

seattle##gs said:
I thought the Alton runs dry

You can run it wet or dry
But it doesn't come with a belt setup like a cnw kit does

concours · Jul 22, 2025

Wash it all with a water soluble degreaser, dry it and spray it with talcum powder developer (foot spray works) and start it up & watch.
Either prove or disprove the theory.

olympus · Jul 22, 2025

1973x75 said:
I had a drip like that on my stock chain case. I used a mirror and a flash light to check underneath, and found it was coming from the new felt seal I had installed. It stopped after a couple hundred miles, inexplicably, but I guess maybe it centered itself. No, I did not let it all leak out, it has a fresh 7 oz of atf.

The leak is directly under the alternator where the oil pools, and since I last cleaned off the area with clutch/brake cleaner I haven't rode it, so definitely not coming from the input seal...the Alton has an "O" rings set up rather than a felt

kommando · Jul 22, 2025

There are paints that will stop porous casting from leaking.

Thread 'Glyptal paint.'

Jul 2, 2025

Do any of you gents have a tin of Glyptal paint they would be prepared to sell me a small quantity of? I just need enough to line a set of crank cases. In the UK it's only available in a tin costing £99, & I'm not prepared to pay that for a single use.

olympus · Jul 23, 2025

kommando said:
There are paints that will stop porous casting from leaking.

Thread 'Glyptal paint.'

Jul 2, 2025

Do any of you gents have a tin of Glyptal paint they would be prepared to sell me a small quantity of? I just need enough to line a set of crank cases. In the UK it's only available in a tin costing £99, & I'm not prepared to pay that for a single use.

Matchless

Replies: 43

Forum: Norton Commando Forum

Appreciate the input, but as the kit was only fitted in May, replacement is my preferred option......that is of course if I get a response from Alton

kommando · Jul 23, 2025

Thread 'Paul Hamon (Alton).'

Jun 11, 2025

I was saddened to hear of the death of Paul Hamon, one of the brothers behind the Alton name. He was very helpful to me on several occasions, and I'm sure many others.

R.I.P. Paul.

MexicoMike · Jul 23, 2025

Yes, me too!! He was great to deal with and extremely prompt to respond.

cliffa · Jul 23, 2025

olympus said:
The leak is directly under the alternator where the oil pools, and since I last cleaned off the area with clutch/brake cleaner I haven't rode it, so definitely not coming from the input seal...the Alton has an "O" rings set up rather than a felt

Personally I would be extremely surprised if it was a porous case. They seem to be very well cast and machined. If you haven’t ridden it, is it still clean underneath? If it is, it’s more likely it’s leaking between the inner case and the crankcase joint when the engine is running I would say.

Also one observation from your first photo is the uneven gap around the cover. It may be worth checking it for flatness. Perhaps your not getting even sealing pressure on the O ring.

olympus · Jul 23, 2025

MexicoMike said:
Yes, me too!! He was great to deal with and extremely prompt to respond.

Absulutely agree, I visited their place in Brest returning from Spain last year proir to purchasing

olympus · Jul 23, 2025

cliffa said:
Personally I would be extremely surprised if it was a porous case. They seem to be very well cast and machined. If you haven’t ridden it, is it still clean underneath? If it is, it’s more likely it’s leaking between the inner case and the crankcase joint when the engine is running I would say.

Also one observation from your first photo is the uneven gap around the cover. It may be worth checking it for flatness. Perhaps your not getting even sealing pressure on the O ring.

View attachment 120904

olympus · Jul 23, 2025

I have just re checked.. the camera angle, crap camera (operator) and lighting is giving the impression of a closing gap, it isn’t
The cover is also brand new & was checked on a surface plate

olympus · Jul 23, 2025

concours said:
Wash it all with a water soluble degreaser, dry it and spray it with talcum powder developer (foot spray works) and start it up & watch.
Either prove or disprove the theory.

Can you clarify please, and you talking about talcum powder or a foot spray??

concours · Jul 23, 2025

olympus said:
Can you clarify please, and you talking about talcum powder or a foot spray??

concours · Jul 23, 2025

Spray talcum foot powder is a readily available substitute for non-critical applications

olympus · Jul 23, 2025

concours said:
View attachment 120907

Excellent thank you, I'll research a UK supplier

concours · Jul 23, 2025

olympus said:
Excellent thank you, I'll research a UK supplier

"Liquid penetrant dye check"

olympus · Jul 23, 2025

concours said:
"Liquid penetrant dye check"

Thank you, penetrant & developer ordered

Primary Oil Leak found

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