250 clutch springs

[dave47]

I've always used the Comma/Wilko gear oil in recent years, so have nothing to compare it with. It is mineral based, and as you say used to be about £4 per litre. It is now about double that so I will shop around.
Some MZ owners used gear oil in summer, such as EP80, and 10w40 or 20w50 in winter. I daresay climate change will make this unnecessary, if it ever was. I used to ride all year round on gear oil with no problems.

[Blurredman]

Hi Dave,



Yes- I think most people still think that one should change the oil twice a year- on anything. That stems from yes the temperature changes but also the fact that oil filtration was not as good on older filters- some cars didn't really have filters in the 50's.. But now we have multigrade oil- so no need to change for winter/summer use. I only change oil once a year. I spend enough on oil- I would have to take out a mortgage to afford that..


Anyway- some people on this forum choose not to change their oil until the mileage has been reached (to contrary the time recommendation).




Would you please update on what you buy and the effects it had? I don't blame you- more than a fiver is too much in my opinion.

[Guesi]

Gearbox oil never had a filter, as far as I know.

The job of gearbox oil is not comparable to the job of engine oil.
That is why I don´t think that it is a good idea to put multi purpose engine oil into the MZ gearbox.
Only because you don´t get negative results in a short period of time does not mean that it is good for the gearbox.

And I never heard that MZ drivers change gearbox oil in summer or winter.

[Puffs]

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[dave47]

And I never heard that MZ drivers change gearbox oil in summer or winter.

Just to be clear, I'm not recommending this. I only mentioned it as an aside to the gear oil versus multigrade debate.

[Guesi]

Hello. I follow the MZ factory, they know the best what is good for these engines.

And who the f... is Mark ?

[nice2day]

I'm not wanting to be different or to be controversial, but after stripping my engine I am going to change the gearbox oil at least once a year and that is likely to be a distance of very few miles, perhaps under 1000. It is not because I believe the oil is worn out but simply that the gearbox oil seems to collect water vapour and this can cause rusting of the steel parts inside the clutch and gearbox. The engine design with its extensive barrel cooling means the crankcases never get very hot ,or hot enough, to dry out the oil.

If one wanted to save money and be ECO friendly you could catch the old oil in a clean container...perhaps a clean Bean Tin and then heat the oil outside on a small stove to around 120 degrees C for about 10 mins or so. This will dry off the water vapour as water boils at 100C. let the oil settle to clarify and cool off, then pour the oil back and top up with fresh oil of choice. EP 80 is recommended by some.

Of course you could heat the entire engine to 120C with a blow torch for about half an hour. This would avoid draining out the oil.....

Les

[Guesi]

It is no question that you should change the oil if the oil is "damaged".

But this is not the normal oil change interval

[Puffs]

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[Guesi]

I think the water comes into the gearbox by defect rubber - oil seals on the clutch cable and and under the round cover with the 3 screws on the clutch cover.

This is my experience....

[nice2day]

Hi Puffs. You covered the chance of water vapour ingress very comprehensively and it makes me wonder if my voiced concerns were somewhat over exaggerated. Thinking about the rust I found in my engine, I have to remind myself that the bike is 32 years old and probably spent most of it left outside in British weather so it's not surprising water had got into the clutch/gearbox areas. As you say there is the vented filler bung which is the most likely point of ingress then the clutch cable as Guesi suggests. The most likely event that would cause a large amount to enter the filler bung is careless hosing down the bike when washing it. The magnetic drain plug takes care of steel swarf contamination so I have to modify my concerns and maybe stick to the approved oil change schedule....if I ever reach that mileage or live that long.


Les

[Blurredman]

Hi,
Agree with the above.

Main contentions of water ingress:

Breather,
Tacho drive entrance (As well as the rubber O ring holding the cap itself on),
clutch cable entrance to case.

[Puffs]

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[Kruh]

Thanks for the link. Was having a bit of a deja vu.

To add a bit of my limited experience.
I never noticed water inside the oil. I did notice quite a bit of rust on the clutch cable, even though it was a brand new cable and rubber cover. I'm putting grease in that area from now on.
As far as the oil goes. I tried 80w90 and just 90. But wasn't happy with either. The clutch is sticky when cold and the gearbox doen't feel smooth (at operating temps).
My favourite so far has been Silkolene light gear oil. It offered no stickines and smooth gear changes. Lately, in the absence of Silkolene, I used 10w40 motorcycle oil (from Total if thats even relevant). Its meant for motorcycles with wet clutches (MA2) and unsuprisingly works well.
Anyways, I think that any motorcycle specific oil should be a good choice (as long as its ma or ma2)

[Blurredman]

This is interesting Kruh, because the whole topic is a result of me trying 10w40 MA2.

I thought that after rebuilding the clutch when I rebuilt the engine (bar clutch springs), I could afford to instead of using 20w50, instead use 10w40 (semi) MA2.. And that is what essentually was causing my slipping, not so much that the springs were dead (although I am glad I replaced them). Removing 10w40 MA2 (after replacing springs for the 2nd time after finding it was still slipping) and then using 20w50 again solved my clutch slip.

I think I will however buy a bottle of 80w for the next time- I can still use 80/90 hypoid oil in other applications so it won't necessarily be too much of a loss of money if I had to drain the oil from the MZ because of inconsistencies in it...

So.. in your application 10w40 MA/MA2 worked.. But not for me.. And I now know that much clutch is in spec. Maybe it was my specific oil manufacture, or maybe the clutch plate material is different in each of our bikes...