ETZ250 primary gear movement?

[BubbleOz]

Hello folks,

following on from my broken oil pump shaft, the MZ recently refused to kick. As if something was 'holding on' to it.
I took off the cover - initially all seemed well. I tried replicating the symptom and.... the primary driven gear (the big 62ish toothed cog) moves up and down???
In the picture, I can grab the cog and move it up and down, but not left and right. Before I source the clutch puller to see what might cause it... does anyone know?
I pray its something simple like a thurst washer/ shim? as I already have one bike awaiting crankcase split...



A video can be found here: http://youtu.be/TfLnR5K9BPA

I am desperate for your collective wisdom , and would be eternally thankful


Thank you so much for taking the time to read my post,
Bubble aka nik

[DAVID THOMPSON]

i am not that familiar with this engine but looks kike you have lost a bearing

[BubbleOz]

I am guessing to replace the drive shaft bearing I... I need to split cases right?

Sigh...

[Phil Krix]

As stated there seems to be little doubt your bearing has gone. Yes you will need to split the cases. However the bearings are standard and you can get at a bearing shop but you need to get the right clearance rating . Can't remember off the top of my head if its C3 or C4, should be in the manual. I am in Canberra and did a rebuild on my engine last year before riding from East coast of Russia to London. You'll find engine strip down videos on youtube which are a great help in addition to the manual. I have tools neededd for strip down, you can borrow if you like. It would be very useful to have access to an oven for the rebuild, however using home oven may bring retribution. You need to be able to heat the cases for a rebuild, you might get by with a really good heat gun but suggest on trash night you keep eye open for a junk oven that is working and get a spraky to fit a power plug for you. Anyway I won't go in for too much further detail at this point but you should perhaps consider doing a full rebuild if you're opening the cases. Feel free to contact for further details.

[BubbleOz]

Phil,
Thank you. You made my day as I am not sure how much luck I would have finding the case splitter I seem to need.
The dread with case splitting is only because my TS185 engine rebuild has gone so wrong with phillips heads stripping I have nightmares but must admit that so far it has been straightforward. The flat head screws are a revelation..
Yes. , I did ask about splitting so I get the full set of bearings. 10 I believe. The die is cast haha.

As for the oven.. I have one I can use whilst my better half is away for the spa weekend I will arrange...

East coast of Russia to London - would have been a formidable trip. Good on ya!

I have got the ball rolling. Bearings..gaskets..clutch puller..even oil pump.

Thanks again,
Nik

[arry_b]

Good grief! That's what an utterly shagged bearing looks like.

[Phil Krix]

Hi Nik,

The MZ bolts tend to be pretty good, when putting it back together I suggest getting replacements bolts for the crankcase joining that use allen head bolts- they are even better. Here is a link and these guys are good for all your spares it you haven't come across them yet.

http://www.ost2rad.com/MZ-Spare-Parts/S ... 0-251.html

Let me know when you need the tools I may need to provide some explanatory notes as they are home made but work fine. Also we can discuss some of the finer points of assembly so you achieve the best results. Some gasket sets are better then others, I found the best paper gaskets are from The MZ Shop http://www.themzshop.co.uk/. I also suggest getting a full selection of head gasket sizes from ost2rad to set the compression ratio. I found that my squish clearance was too big even with the thinest - but everyones will be different.

The reason for the oven comment was that whilst its not too bad using the home oven for assembly it definitely makes it easier to stick the whole lump in (minus the head and barrell!`) the for disassembly and its too hard for mere mortals to get all the oil out so you'll could end up with a very smelly oven/ktichen. Oven at about 150 Degrees C seems to work wonders and provided you got some good welding gloves it should come apart very easily, so no damage to bearing surfaces. Enlist the help of a good mate!

By the way I would suggest some Welseal for joining the crankcases unless you have preference for others.

Good luck with everthing. If you're on facebook check out MZ Adventure.

Regards
Phil Krix

[mr_luke]

I find the smell can be avoided if you line the bottom of the oven with aluminium foil, and sprinkle a good layer of bicarbonate of soda over it before you start. When you've finished, turn it right up for 10 minutes and leave the door open until it cools. I've managed to get the job done during a shopping trip without being detected that way! I'm lucky enough that permission will usually be granted if I promise to clean the oven afterwards, though...

[Phil Krix]

Thats good advice, I'll try it!

[DAVID THOMPSON]

my problem is the apple pies taste funny when she uses my oven in the work shop
without telling me to clean it out first
dave

[BubbleOz]

It is amazing what can be found inside a clutch cover..
BONUS QUESTION:

- Anyone know what these things are???

[DAVID THOMPSON]

the metal retainer for the BALLS in the bearing

wash out the mess do not cut corners on the clean up of parts

dave