Author Topic: Copper-colored dust in return oil  (Read 1220 times)

Online RichardL

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Copper-colored dust in return oil
« on: 10.04. 2010 21:57 »
Gents,

I just started up the engine following near completion of the "winter" work. She runs great, but I noticed what appears to be very fine copper-colored dust suspended in the return oil. It seems to me that if this is indeed copper or bronze it can only have come from rod or timing-side bearings. Nevertheless, as I said, she is running great. I wonder if this is much concern. Maybe it is an optical illusion from the fine bubbles in first-start oil. My inclination is to think there is not much I can do, even if it is metallic dust. I suppose I could change the brand-new oil just to be careful. Does anyone have thoughts on this or have seen it before?

I want to tell about the winter fixes, but first things first.

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020 (if it's not cancelled and we are free to move about by then). Watch website at https://www.gentlemansride.com for details.

Offline a10gf

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Re: Copper-colored dust in return oil
« Reply #1 on: 10.04. 2010 22:34 »
I've seen bronze\copper dust as well, both in gearbox and engine. As for the source, never 110% sure, but in my engine I have a worn plain bearing to replace. In your case it may just be byproducts of running-in, and in any engine fitted with some oilfilter one would never have seen it or worried about it. No unexpected noise, I suppose, so change the oil after a while, and probably the amount of fresh 'gold' will decrease.
Just some thoughts.

Regards
e

A10 GF '53 My A10 website
"Success only gets you a ticket to a much more difficult task"

Online BSA_54A10

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Re: Copper-colored dust in return oil
« Reply #2 on: 10.04. 2010 22:58 »
Change the oil twice after a short while.
Keep the oils seperate in a sealed container ( 3 liter drink containers work well )
Bearing detritis should drop to the bottom as copper is heavier than oil.
If the bike has been standing for the off season it could be dust, dead moth wings any sort of crud.

Check all 3 containers after the last one is filled.

If the mystery dust is decreasing with each oil change then it is probably some forein crud.
If it is increasing in either volume or size of particle then it is time for a full investigation 
Bike Beesa
Trevor

Online trevinoz

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Re: Copper-colored dust in return oil
« Reply #3 on: 10.04. 2010 23:04 »
Richard,
                Did you replace the timing side main during the "winter work"?
I had the same with my Flash after the engine rebuild.
It was only in the first drink of oil, OK after oil change.
I think it was only the high spots wearing off the bearing.
Trev.

Online RichardL

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Re: Copper-colored dust in return oil
« Reply #4 on: 12.04. 2010 15:46 »
Gents,

Thanks all for the mostly reassuring comments and advice. After reading your thoughts I had another bad thought of my own. In the winter work, I replaced all the valves and two of the guides and I could not recall if I had lubricated the valve shafts before assembly. This would not be a good thing regardless, but I think the metallic dust showed up too soon to be something washed down from the guides. Nevertheless, feeling a deep fear, I pulled off the rocker covers to see if I could detect any problem. Of the two guides who's tops I could glimpse through the springs, there appeared to be no problem and things looked moist. Anyway, I gave a heavy squirting of oil through the springs and towards the guides, just for peace of mind. So far, still no noticeable bad sounds.

Erling, good point about the oil filter and, of a sense, good to hear that someone else has seen this without catastrophic results.

Trevor (54A10), I like the idea of the empirical approach of measuring the dross to assure that it is diminishing. I like, even better, the idea of it being moth wings, but I assume that was a bit of kidding about. As for 3-litre soda bottles, maybe the rate at which I change oil will parallel the rate at which my kids can consume Diet Coke.

Trev, I did not replace the timing side bearing (except about 1400 miles ago). Again, good to hear from another experienced member that this was not a disastrous phenomenon. Hey, but time will tell. If I could just go a few years without major rebuilding I would still be happy, I think. (I may have a psychological problem that requires me to be working on the bike in order to be happy.)

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020 (if it's not cancelled and we are free to move about by then). Watch website at https://www.gentlemansride.com for details.

Online BSA_54A10

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Re: Copper-colored dust in return oil
« Reply #5 on: 14.04. 2010 10:35 »
Yes I have pulled down a perfectly good engine to try & find the source of the crud in the oil.
Source was my habit of draining the tank & leaving the cap off ( So I did not forget to fill it before starting the engine )
Mayby it is a local thing but Hawk moths seem to love modern oil.
Hey die in the tank and the wings "turn to dust" which sits on top of the oil in the tank.
Bike Beesa
Trevor