MZ/MuZ Riders

Hi everyone. I have managed to separate the crankcases and have stripped down the rest of my Saxon 301 engine.
I am baffled by the metal discs that are inboard of the crankshaft oil seals and are next to the crankshaft main bearings. I realise these discs guide the oil into the ball bearings, but the discs have a small dot of metal near the edge that has to be lined up with the oil delivery hole. As the discs are simply steel discs with no other difference anywhere around them I am intrigued why it matters that they have to be lined up in a particular way. Does any one know? I cannot see why it should be so, I look forward to any ones idea on this. Many thanks.

Hi,
Have you got any photo's or pages from a workshop manual to describe what you mean?
Thanks.

David

http://www.mz-b.com/k251/251t44.htm

Part no: 14 shown on the crankshaft diagram. or MZ part no: 29 43 105

Thanks.

Hi,
I've just watched this video

http://www.youtube.com/watch?v=oIh2Zm2J4Ss

and from what I can gather the punch mark probably creates a deformation in the disk that allows the oil to be channeled towards the bearing races. Also the plate is placed so that the central part of the it (which is curved) can form a kind of well for the oil.

The next video in the series is

http://www.youtube.com/watch?v=DqHKG-WC ... re=related

Which may explain it a bit more as well.

HTH.

David.

what am information gold mine for the 250/251 owner
does any one know if that series of movies is available
some where on dvd
the speed of my internet down load makes it hard to watch

the beauty of the 250/251 is it's easy to fix and if not beat and thrashed
would make a very good daily driver
dave

DAVID THOMPSON wrote:does any one know if that series of movies is available
some where on dvd

Thompson, I can make a CD copy for you.
Please, send me your address.

Saludos/Regards

David, if you read my previous post: Crankcase separation MuZ 301, you will see that we discusses the source of these videos at MZ owners club Hungary. You will then be able to view the complete set. They are all excellent.

Looking again at the rebuild video, I am now confused what way round the discs fit. The witness marks on my used discs indicated that the dishing faced outwards but the video makes it appear that you fit them with the dish facing inwards, but this could be an illusion. Does anyone know for sure what way round they fit?

My theory is that the small cenre punch pip stops any chance of the disc rotating. If it starts to turn in sympathy with the rotating bearing, the pip will hit the open end of the large retaining circlip and will remain stationary. This will only work if the pip faces outwards towards the circlip. Is anyone with me on this idea? I dont think the pip is used for oil guidance but I could be wrong.

Hi,
Yes, youre probably right, it probably stops the plate from turning and has nothing to do with oil guidance.

David.

if it spins then the oil will build up at the bump and be slung off in a even manner
dave

Just to say that after many repeated replays of the oil disc fiiting in the video, I can be happy that the pip on the disc does indeed face or protudes outwards and can be trapped by the circlip ends if indeed any turning was to take place.

As an additional point, it seems difficult to see how any amount of oil can get to the main bearings as they are shielded and in flush contact with the oil disc. Very odd indeed! The only way I can see is that oil collects in the outer space between the disc and the oil seal which eventually fills up with oil to the level of the shaft. The oil then somehow gets past the tiny clearance between the shaft and the centre hole of the disc and eventually gets to the bearing centre and is then circulated in the bearing.
It works though.

Hi,
There must be some deformation of the disk around where the punch mark is. It's probably enough to allow some of the oil that comes out of the oil drilling in the crankcase to flow into the edge of the bearing. The bearing on the video is only sealed on one side isn't it? The side without the seal faces the plate I think.
Anyway, as long as it works it should be OK.

David.

Sorry David, the way I constructed my sentance looks like I suggested the bearing was a sealed type. I didn't mean to say that. What I should have said and made clearer was that I considered the outer face of the bearing was in such close contact with the oil guide disc there was little chance of oil getting to it directly from the small hole feed hole. But the bearings last well so they must be getting some oil.