Any ideas?

[penman]

The clutch on my 1978 500W has been getting increasingly difficult recently, so this afternoon I stripped it down for a clutch overhaul. I rebuilt the engine about 12,000 miles ago, so although a clutch overhaul was probably a bit premature, I wasn't too concerned about having to do it again. Anyway, there was some oil on the clutch plates so I decided to take the primary case off and replace the seals, etc. Now the trouble starts. There was a small amount of sludge in the nooks and crannies of the primary case and cleaning it out I found half a washer lodged in a corner. It's a standard M6 steel washer, of which there are dozens on the Morini. There are several similar washers located in the primary case, but they are all present and correct.



So where did this half washer come from? It's broken cleanly more or less in half. It isn't mangled or showing any other damage, not the slightest mark, so I find it a bit hard to believe that (for example) it was caught in gears or something similar. It does show a circular polish line, presumably from a screw head. So where it came from or how it got in there is a mystery. But is there another half in there floating about in the oil, ready to cause untold damage? And if there's another half somewhere, does that mean there's a loose bolt somewhere?

Well at the moment, I can see no alternative but to strip the engine down and go on a washer hunt, but I really don't want to do that, I've plenty of other projects waiting to be done and besides, the engine is running really well. So any ideas, suggestions or comments would be most welcome! Many thanks!

Joe.

[MickeyMoto]

drain the oil and remove the oil filter cover. Run a magnet around inside the crankcases. I did that when I dropped a washer in there! (Don't ask).

Unless the washer is stainless...

[3potjohn]

The magnet trick is a good one, also a bright light. Trying to think where a M6 washer would be from. From the top end I would think unlikely or impossible. Any chance of a frame washer falling in to a partly dismantled motor?
Certainly there are “small “ washers on the oil pressure relief, the oil pump and oil delivery hole, which are visible now you have the cover off. On the other side I can only think of the stopper plate. The two hidden through bolts have a copper washer on one end. Not sure any are actually M6 though. You would have thought if it had got into the oil pump worm it would be obvious.
If you find the other half so much the better.
Good searching.
John

[penman]

First of all, thanks for the ideas! I did drag a magnet through the oil I had drained but no joy. I didn't think to put it on the end of a piece of wire and drag it through the crankcase, so I'll do that. I do have a borescope so I'll have a go with that as well. John, you mentioned the "stopper plate" - is that the one for the gear selector mechanism? I do remember it is retained by two small bolts, possibly M6 and I had to loosen them to adjust it. I can't remember any other small bolts in there. In my recent house move, my Morini parts book seems to have gone awol so I don't have any diagrams to jog my memory, if anyone knows of a downloadable 500 parts book, that would be much appreciated. I'll have another search for mine this afternoon though.

I'll let you know how I get on!

Joe.

[MickeyMoto]

One other place is from the top end. Would it be possible to drop a head bolt washer down the pushrod opening in the barrel, especially the one under the pesky allen bolt? Not sure it would get to the crankcase.

[mbmm350s]

3potjohn says
From the top end I would think unlikely or impossible


what about the M6 allen head screw with washer for the head to pushrod tunnel , they seem to be blackened, not sure how it could have down to the bottom though, but easy to check in minutes..

The retainers for the bearings are thick/large washers so probably not from there.
Just leaves the stopper plate I think as john mentioned, yes the one that adjusts the selector mechanism. If the plate had come loose though wouldn't gearchanging have been different?

Mark

[penman]

Well I've had another look round and I'm feeling more confident that there's nothing loose or floating about in the engine. I've checked those two Allen head bolts in the cylinder head behind the pushrods and they are both OK - washers in place and complete. I spent some time poking the borescope in through the various holes and I'm pretty sure there is nothing lying in the bottom of the crankcase. I also dragged the magnet around in there but came up with nothing. I haven't managed to locate the gear selection stop plate and I don't really remember what it looks like. I seem to recall a small metal plate, maybe 5cm long, bent at right angles and with two small bolts fixing it to the side of the right hand crankcase half via slotted holes - but I could be imagining all that! If I knew where to look I may be able to bend the borescope probe the right way to see it, but wherever it is, something was blocking my view. I rather doubt if that is the problem though, if that plate moved even a little I think the gear change would be greatly affected. By the way, I do have a spare gear cluster which I laid out on the bench. I can see and identify every part of it - except that wretched stop plate.

Eventually the batteries died in the borescope, putting an end to the fun and games. I might have another go tomorrow.

At the moment my favourite theory is that that washer fell in sometime during an oil change or whatever. So far everything supports that, but I'll probably have another round of hunt the washer before I give up.

Thanks again for your replies!

Joe.

[72degrees]

The stopper plate is as you describe and screwed to the case as I recall, so not part of the cluster. I would expect a 'sloppy' one due to a missing screw washer would be reflected in the quality of the gear change.

Are Morini drain plugs 'magnetic' as standard. I misremember (shows how long since I changed my oil )

In some ways, better if the seemingly missing half is down below rather than up top. A neighbour managed to lose a glow plug heater connector washer down the plug hole of a Peugeot XUD diesel. Didn't notice - turned over the engine and it got stuck under a valve

[penman]

Well I finally located the gearbox stopper plate. In fact it's in the left hand crankcase half and the two mounting bolts come through from outside, in the primary case. With a bit of judicious bending, the borescope can reach it through the oil strainer hole. Both nuts and washers are in place and undamaged. So I'm pretty well certain the washer didn't come from anywhere inside the engine, meaning that it must have either fallen in sometime, maybe during an oil change - I often leave it overnight to drain down fully and I leave the dipstick out while that happens - or I left it in there somehow when I had the engine apart last time. I would like to think that's very unlikely, I do try to be careful! But I guess I'm not infallible, so that remains a possibility. I'll never know, but I'm confident enough not to do a full strip down at this stage.

In reply to a question, the sump plug is not magnetic, though I believe there are some after-market ones around. There is a deep recess in the plug which can catch debris, etc but apart from a small amount of sludge, there was nothing in there. It's only about 1500 miles since the last oil change and it stays pretty clean.

So I think that's the end of this story. Hopefully there won't be a sequel where I explain how I was proved wrong!

Regards,
Joe.

[norbert]

If you cannot find anything and there are no strange noises, just keep on roling

Once I´ve found a small piece of a tube about 10 mm long with an inner thread in the rocker box, that must have been there for thousands of miles. Of cause I couldn´t claim anybody but me. I´ve put it on the shelf and it took me years till I found out that it was the top end of an oil can (I use to give a drop of oil on the rocker when getting them off an in).

[3potjohn]

I recently found a spring approx 10mm by 3 mm diameter under my Beemer. It is not from that bike. I checked my pilot screws on the nearest Dellortos and nothing missing.
I use neodymium magnets on all my drain plugs.
What boroscope do you use?

[penman]

Hi John,
Apologies, only just noticed your reply and question. My borescope is a cheap & cheerful item I got from Lidl one time with the "Powerfix" name. I'm sure there are much better ones around and I like the ones which link to your phone by bluetooth. Having said that, the one I have is generally more than adequate and the price was right!

The existing sump plug doesn't have a magnet - how did you fix your neodymium magnets to the plug? I did think I might drill & tap the plug and fix one of the small circular magnets on with a small screw.

Joe.

[3potjohn]

The neodymium magnets were obtained from Cermag some years ago. It is a qiute brittle metal so and these are nickel plated to prevent corrosion. They are about 20 x 10 mm. I clean sump drain bolts on bikes then use epoxy.If it ever comes off when spannering it can be refitted again, once you have dislodged the spanner.Two together are very difficult to pull apart. There is usually ferrous material stuck to the exterior from “road dirt”. I had a self induced gearbox issue last year and the shards were on the inside of the plug.Well maybe all of them!
Just seemed like a good idea. Cermag part no NE35 over 6Kg pulling force. I have yet to collect a manhole cover. Does not seem to interfere with the generator side.
John

[penman]

Thanks for the info John, and especially for mentioning that the neodymium is brittle, I didn't know that. The ones I have are very small, about 10mm diameter by 3mm thick. They have a countersunk hole through them which is why I was thinking of screwing it to the sump plug - but I don't want to crack them with the pressure of the screw. I'll probably try some kind of adhesive. As you say, the magnets are incredibly powerful, so I'll be careful over manhole covers in future!

Joe.