Hello all airhead riders,
few days ago I found a couple of metal pieces in my sump. They are roughly 2x2mm and 1mm thick. First I thought they are a piece of a roll pin (also called spring or tension pin) but I don't see such a thing while looking at parts fiche. Otherwise the engine runs normally, no strange noise and the oil looks appropriately. Has anyone found similar pieces in their sump? Please let me know.

Jiris

A picture would help. Maybe you want to check and see if your missing any of the needle bearings from the rockers. Otherwise, could be a bearing cage?

Yes we need a pic and the correct dimmensions.

There are usually only three things you can find in the sump.

I'm afraid that I can't get a picture. I'm 2000 km away from the bike now. I know that locating pin of the front crankshaft bearing or a needle from rocker bearing can appear in the sump. But neither of them looks like pieces I've found. I got an idea it is a part of rocker bearing cage but pieces from my sump are hardened and I don't think bearing cage is hardened. Alibaba, could you please name the three things you mean? I'll appreciate any help.

You have mentioned two (locating pin and needle from rocker bearing).
The only other thing I can think of is the rocker-shims.

If what you see is the cage of the rocker-bearing it usually has traces of a round shape.

They definitely aren't rocker shims. It must be something unusual. I'll try to get a picture.

I finally managed to get some pictures. They are not of the best quality but I hope they will help to identify where the pieces are from.

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You're right... pictures are a little hard to see but it looks to me like they could be pieces of a valve collet. Hard to imagine that they could work their way out of the spring socket but guess it's possible. In any case, if it is a broken collet (valve keeper) you need to get it fixed before the valve drops. For what it's worth, that's my armchair guess. If it is a keeper, I'd keep all the pieces and see if I could account for them all. Maybe pop the valve covers and see if there is any debris around. Yikes! Good luck.

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Samuel Longiaru
Kamloops, BC Canada
1975 BMW R60/6

This is a hard one.

When you opened the sump did you take a look at the area around the conrod and main bearings?
The parts look small so it might have come all the way to the oilfilter.

I would have started with ripping the valve covers off. If it comes from that area it will probably still be some pieces left.
If that fails I would have removed the generator and the timing cover (you will need one gasket and two small gasketring to re-assemble this) and inspect the area around the camchain tensioner.
It’s also possible to roughly inspect the front main bearing with a 0,1mm feeler gauge when you are in there.

Thank you guys for your input,

I'm pretty sure that those pieces are not from valve collet. I took cylinder heads off and inspected valves, guides, springs, spring retainers and collets and everything looked good apart from worn exhaust valve guides. The only thing which I was concerned about was slightly bigger valve clearance on the right exhaust valve. It was 0.30MM.

I had a look at conrods, crankshaft, camshaft and cam followers while sump was off and I didn't see any problem. Unfortunately I haven't removed oil filter so I can't say what's inside.

I'm going to have a look at timing chain area. New chain and other parts needed are on order now.

I wont get to my garage until mid-April and than I'll have only few weeks to sort everything out. I hope this is not going to ruin my plans for summer trip.

I know nothing about this engine and you don't say what you have as history for your bike (unless I have missed it via some other thread).
Nor do you have any problems with the bike at present.

Years and years ago, in the bad old days, it was not unknown (please excuse the double negative) for plumbers to throw a handful of steel nails into a copper cylinder before finishing off the soldering and sealing the cylinder: this practice ensured galvanic corrosion and the destruction of the cyl over a number of years: the thinking was that this would ensure continuity of employment for plumbers in the future:- a sort of built-in-obsolence, something which also occured in, for example, the car manufacturing industry.
Could you have a somewhat similar issue?

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Dave

Wow, interesting! They do look like valve keepers, but you definately would of dropped a valve by now if that was the case. Now, could it be oil contamination, like it was poured into the engine from a dirty funnel? Also, pull your plugs and turn your engine over by hand, feel and listen carefully for any roughness, it should be smooth throughout the cycle and pretty much quiet except for the sound of air escaping the cylinders. Keep us informed!

They are VALVE COLLETS For sure - cant understand how the valves have not dropped. Is your oik filler locked or safety wired? someone could have dropped them in. They do not look like bearing cages and that is the only other thing I can think of. Have a good look or you next ride could be very expensive!!

I'm back after a week of working on my bike and I have an explanation where the pieces came from. They really are pieces of spring/tension pin as I thought first and they are specifically pieces of one of positioning pins that hold thrust bearing of the crankshaft in place. I have no idea how it could brake. The other pin was OK and nothing else was damaged. Was the pin overhardened? I managed to change the pin without taking crankshaft out of crankcase.

BTW, does anybody know if crankshaft is balanced together with clutch or are they balanced separately?

They can brake if the spacer/shim and locating pins don’t line up when swing wheel is tightened.

From factory the crankshaft, and various clutch parts are balanced separately.