Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board Magnetic Oil Filters

I know that sump filters can be fitted (A65) although the studs on mine have previously been fitted with M10 studs, presumably as one has been stripped. Also there are magnetic devices to attach to filter cannisters.

It got me thinking, are there any downsides to placing a bar magnet inside bottom of oil tank? Vibration could be one, although a strong magnet should clamp firmly enough.

Interesting idea. Maybe you could figure a way to install the magnet in or with the tank drain plug fitting/screen? Then it would be more available to inspect and clean at oil change.
I will add that when I cut open the spin on filters I use, the results show bits of black carbon, and shiny alloy flakes. A magnet dragged through the filter has yet to find any iron,….. so far anyway!

Buy some of the super strong mini magnets of ebay/anywhere , I buy ones about 10mm x 5mm . I stick one on my filter, drain plugs for good measure and forget em, seem to stay on ok. I've never noticed any concerning amounts of ferrous paste but for what they cost it doesn't do any harm for a bit of novel piece of mind.

I think it's a step too far for me to attempt that within the gauze filter, but a magnet could be placed close to the gauze itself I think; can't quite remember the available space until I do next oil change.

KevRasen- I'll try that with a similar sized bolt and see what strength remains at the other end.

You're over thinking it mate. With a decently built engine, running clean/regularly changed oil and an inline filter you shouldn't be suffering much debris in the oil/engine. I check the magnetic sump plug on my A65 each oil change, circa 1500-2000 miles, and at most there is a very thin cover of what I assume to be ferrous paste, I wipe it off, replace it and think "that seems ok for a 50+ year old BSA" and off we go.
I also keep a magnet on the oil tank drain plug/filter and have never found any ferrous paste there..
Ditto one also on the gearbox drain plug and again have had nothing on it.
The small(ish) neodymium magnets provide sufficient magnetism through the length of the sump/drain plugs to still give enough magnetic effect on the other end, obviously the bigger the magnet the bigger the effect.

Considering you've experimented and I haven't, you have the knowledge! My expectation of huge clumps of metal particles encrusted around each maget after 500 miles have been dashed.

Even though your sump studs are M10 (which seems way oversize), it should be possible to use one of the alloy sump plates available which have a magnetic drain plug. You will have to drill out the mounting holes to fit the M10 studs.

I agree with KevRasen, and maybe an alternative approach is to use the neodynium magnets (type N52), on the outside of the original steel sump plate.

The N52 magnets should stay in place given their high strength and although on the outside of the sump plate, they should still attract a lot of ferrous debris.

There is a sump magnet in my Commando plus a modern paper filter in the return, the magnet was a bit furred up every oil change until I went full synthetic 10/60, then nothing.

Just for fun,…. Got any of those older Sonocare cordless tooth brushes laying around? They stopped using the old design some time back. I was told it was because the replacement brush magnets got too expensive. Those little buggers are STRONG!! I’ve saved many, and epoxy them to things. Makes a dandy hide-A-Key….. anyhow…. This small magnet could easily be epoxied to that drain plug screen, or maybe stick it on the return oil “spout” in the tank? Maybe not, they are hard to get off…..

If your seeing huge clumps of metalic particles then I'd stop running the bike and strip it down. a magnet in the sump cover (like those available from SRM) and an oil filter on the return line will take a couple of garage hours and save a lot of issues in the future.

In addition to that, if you get one of those pump up vacuum devices for sucking up oil then you also remove any sludge/sediment collected at the bottom of the oil tank.

Or do this. But, be carful as too much magnet can suck the oil pickup tube ball down.

Those look to be real strong.

Another extremely strong magnet are the two that are in computer hard drives. Stick'em to something and you can hardly get them off.

Just jesting about the clumps of metal!

Yes, I've got a 12v oil pump, saves a lot of potential spillage, but I've found that by wrapping a long phillips driver with rag, any remaining sludge can be brought away.

Keeping the oil tank clean is a good thing and I don't mind overdoing it. After draining the oil tank, I reinstall the gauze filter and plug the tank outlet. Then I pour some degreaser into the tank and agitate the liquid with an air blow gun and a short length of hose. When I've drained the degreaser and blown the tank dry, the inside is really clean. My floor is not.

If you fit that style of sump, put it on sideways so the drain bolt is on the side stand side
Firstly it makes draining the oil easier
Second when you forget to replace the drain plug the oil blows out the left side of the bike rather than being dumped directl onto your rear tyre