55 Primary chaincase - again!

Information relating to the Matchless G9 or AJS Model 20 500cc twin
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Re: 55 Primary chaincase - again!

Postby ajscomboman » Sun Jun 23, 2019 6:43 pm

[quote="rudelan"]No oil in chaincaise... only
Geloil 5095 on chains and. Clutch

-->>For grease lubricated gearboxes, characteristic for the years 20/40, it is not recommended to use a 'thick' grease because the rotation of the axles will fling the grease off and the gears will run 'dry'.
The use of oil, even viscous, is hardly possible, due to the only rudimentary sealing of these gearboxes.

The semi-liquid Restom Geloil 5095 is a thixotropic grease :

- Jelled at rest -gt; no leaks
- Liquid in motion -gt; lubrication possible without centrifugal action.

Does not affect the seals.

Features: Has an anti-corrosion action and high wear resistant properties.


Nope, you're wrong there. Definitely oil in the chaincase. SAE30 it's required to lubricate the clutch rollers and the cushdrive on the crank shock absorber

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Re: 55 Primary chaincase - again!

Postby Mick D » Sun Jun 23, 2019 6:57 pm

Errrr

How is using grease in the chain case going to resolve the engine oil scavenging issue? :?

Regards Mick

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Re: 55 Primary chaincase - again!

Postby REW » Sun Jun 23, 2019 7:20 pm

rudelan wrote:No oil in chaincaise... only
Geloil 5095 on chains and. Clutch

-->>For grease lubricated gearboxes, characteristic for the years 20/40, it is not recommended to use a 'thick' grease because the rotation of the axles will fling the grease off and the gears will run 'dry'.
The use of oil, even viscous, is hardly possible, due to the only rudimentary sealing of these gearboxes.

The semi-liquid Restom Geloil 5095 is a thixotropic grease :

- Jelled at rest -gt; no leaks
- Liquid in motion -gt; lubrication possible without centrifugal action.

Does not affect the seals.

Features: Has an anti-corrosion action and high wear resistant properties.
Packaging: Can of 1 litre.


Sounds like the Morris K400EP I use in my 2 Burman boxes. I add some 50wt to mobilise it a bit and leakage is certainly much less than with just oil. Gear change is fine.

I have often wondered about using it in the primary case - and I know Rob does not think it a good idea. Have you done this Rudelan?

As for felt filters, I have suffered with these and yes, if the filter blocks the oil outlet in the tank filter tunnel oil return is severely hampered if not stopped. Run without a filter to check it isn't the cause, no harm will come from doing so.
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1951 Matchless G3L, thumping round the Durham Dales

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Re: 55 Primary chaincase - again!

Postby Oggers » Sun Jun 23, 2019 9:53 pm

I am still not getting why a blocked foam filter should cause a build up of oil in the cranckcase. According to the manual :o , oil is delivered to the crankcase filter housing, pressure builds, releases oil to the the engine etc and oil returns to sump to be scavenged and fed back to tank. Surely if the foam filter is blocked it restricts oil flow to the engine etc and actually reduces the chances of oil building up in the crankcase. Scavenge pump just scavenges direct back to tank - no mention of filter involvement on the return line - and as you say, if it is a bigger capacity than delivery, then sump should be dry....or am I missing something very obvious which I will deeply regret the moment someone points it out.

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Re: 55 Primary chaincase - again!

Postby REW » Sun Jun 23, 2019 10:46 pm

The filter in the "return line" is the one in the oil tank filter housing tunnel. It is felt not foam (also true of the one in the crankcase). And yes, if it becomes blocked or flops over in the oil tank housing it will impede or even stop the return flow so the oil will not return but fill up the crankcase. This I know from personal experience. Remove the filter in the tank and the scavenge pump will empty the crankcase contents back into the oil tank.

Of course this all assumes your fault is with the tank filter rather than anything else. Easy to check - remove the filter.
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Re: 55 Primary chaincase - again!

Postby Mick D » Mon Jun 24, 2019 5:53 am

Hi

This is the filter you need to investigate, (illustration from the 55 twins owner's manual):

Tank Filter.png


This is in the return line and will cause scavenge problems as described above.

Regards Mick

Out of interest, can anyone advise as to whether the pumps can accidently be transposed?
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Re: 55 Primary chaincase - again!

Postby rudelan » Mon Jun 24, 2019 6:21 am

Check if the discharge valve is not continuously open. Diaphram and spring changed?
I also installed a tap on the oil inlet, this prevents the crankcase from being filled by gravity with oil that can flow down to the engine.

PS:
On my Royal Enfield, I had installed a large pipe on the discharge pipe connected to this outlet on a small tank. After each long drive, I emptied this small tank into the main oil tank.
Last edited by rudelan on Mon Jun 24, 2019 7:08 am, edited 1 time in total.
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Re: 55 Primary chaincase - again!

Postby clive » Mon Jun 24, 2019 6:55 am

Mick D wrote:
Regards Micky

Out of interest, can anyone advise as to whether the pumps can accidently be transposed?


Yes the two pump units can be reversed on the pump plate.

I Became concerned that this was the problem on my G11CS when I first ran it as the chaincase filled on quite a short run. However in my case the problem was that the drilling for the return of the oil in the crankcase was blocked by a bit of broken piston ring. I was lucky and it was flushed out when I emptied the oil from the crankcase with the engine hot.
As suggested earlier a test which may indicate either the pumps are reversed or the return flow is blocked is how the oil returns into the oil tank. There should be a steady flow until any wet sumping has been cleared at which point it should become broken and pulsing. If it is always a constant flow the pumps may be reversed as the supply should be less than the return capacity.
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Re: 55 Primary chaincase - again!

Postby Oggers » Mon Jun 24, 2019 10:31 am

Mick/Ron

Arrrgh! I have just noticed on my printed downloads for workshop and owners manuals that they date from 57 onwards! I guess the large hex nut on top of the oil tank should have been a giveaway, but in fairness bike is in the shed at present...


Your comments thus make perfect sense. I shall clean and inspect forthwith!

Very many thanks.

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