Felt filter

Information relating to the Matchless G12 or AJS Model 31 650cc twin
bob121
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Felt filter

Post by bob121 »

I was just wondering the other day about the felt filter. As to whether or not it was good enough to run a detergent based oil. Anyone tried.
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Rob Harknett
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Re: Felt filter

Post by Rob Harknett »

I guess plenty of people use detergent oil. I do not ever recall anyone mentioning the suitability of the felt filter. So all would have still used the filter unless they had made mod's.The only thing related to filter, would be, detergent oil will shift muck in a dirty engine. So warning of blockages mentioned. This would also apply to the oil filter having to filter out more muck. So would need more cleaning.
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dave16mct
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Re: Felt filter

Post by dave16mct »

I would only use 20/50 detergent oil in a newly rebuilt twin engine with a full flow remote filter in the return line.
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bob121
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Re: Felt filter

Post by bob121 »

dave16mct wrote:I would only use 20/50 detergent oil in a newly rebuilt twin engine with a full flow remote filter in the return line.
Dave.
This is what I thought. The internal filter would be overwhelmed. But what about once the engine is run in. Would it still be too much for the felt filter. To run it the way I want to, I guess I will have to fit a canister filter.
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Rob Harknett
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Re: Felt filter

Post by Rob Harknett »

I have run my bikes since they were almost new up to now. Still using the same standard filter's. I've used old type straight oil, detergent and multi-grade. In the past 30 odd years I have never replaced a filter. Just washed in petrol very few times. I have not noticed any difference. Although not oil bikes, return the same. Prewar bikes seem to return faster. Perhaps because oil is not going to the top end. This seems to suggest, give the pump more to get the oil through, expect a slower return. So take care extra or new type filter's do not act like a partial blockage.
dodger
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Re: Felt filter

Post by dodger »

I have a 1961 CSR engine, a 1960 CSR engine, a 1958 G11 engine a 1958 G2 engine and a 1960 Triumph pre-unit engine.
They have all been run on 20/50 oil with standard OEM filtration for countless thousands of miles between them, none of them have given any problems whatsoever as far as oiling is concerned.
Change the oil at regular intervals and you will have no problems.
A lot of hysterical nonsense is written about what oil to use or not to use.
Mick D
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Re: Felt filter

Post by Mick D »

Hi

I can see no reason not to use detergent multigrade in an engine that has been thoroughly cleaned / overhauled, (don't forget to flush out the oil tank and lines).

On a twin an external cartridge oil filter will provide additional filtration which is nice to have, (if you're not a 'rivet counter'), but not essential and will increase the load on the oil pump.

On a single, the plunger oil pump is working pretty much at it's limit and I wouldn't increase it's workload by adding a cartridge filter, just stick with what was originally installed.

Regards Mick
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Rob Harknett
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Re: Felt filter

Post by Rob Harknett »

I have a 91 year old AJS that has no inline or cartridge filters also a 99 year old Hayward. Plus a few 50's 60's bikes. Is there any real need to try and better a life expectancy that has already proved good for up 100 years. Also the bikes had to work hard in all weathers and poor road surfaces. They survived without air filters, inline oil filters etc. They get a much easier life now than they got in their first 20 years. Most not even leaving the shed all winter. They get no oil circulating at all then. Pay more attention to your engine having oiled parts, any oil will do, better than nothing. Just keep them oiled when not in use. That will do far more good than trying to improve oil type and cleanliness for the few hours the engines are run.
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dave16mct
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Re: Felt filter

Post by dave16mct »

Rob, while I agree with all that, it doesn't relate to Bob's question. His 1960 twin has high pressure oilpumps and plain white metal bearings, so needs good filtration. Dodger, I didn't mean to suggest the use of detergent oil. I was just answering the question and recommending a remote filter in the return line if detergent oil was used. Surely an extra filter can't be a bad thing on a twin?
Dave.
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1608
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Re: Felt filter

Post by 1608 »

A friend has owned a 70's Triumph oif from new and this only uses a strainer type filter ( not a felt one) and its never been apart or given any problems. My Ariel Huntmaster only has a strainer type filter and when I rebuilt it there were no signs of excessive wear. I have therefore removed the felt filter on my G12 ( considering AMC never really got to grips with the oiling on twins anyway) in my view to assist with greater flow to the main shells instead of pouring through the PRV. I believe the felt filter to be restrictive especially with cold oil.I do however believe in regular oil changes.
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