MZ/MuZ Riders

Hi friends,
despite my extensive searches, have not found anything relevant to my problem anywhere... so would like to tap into your collective wisdom .
I am a proud owner ofan 1981 ETZ250. It is my favourite ride, and well, on the whole she is reliable...

Symptom: After filling up the 2T tank , about 3Km's into the ride, at the lights, there is a complete MESS of 2T oil. Not the 'problem' where if its overfilled on a hot day some will escape from the vent tube, this is a lot of oil collecting and dripping all down the back of the engine, stand, and rear tyre.
I managed to limp to work, as the clear oil feed pip into the bottom of the cylinder emptied. To get her back I will guesstimate my premix ration on the oil-rich side.. and ride home.
Upon inspection, I noticed this thick rubber bung or plug, which is slightly out. My attempts to work out what the plug plugs (is it crankcase breather??) or indeed what the hole in the back of the engine is which is not in any manual has puzzled me. Would 2T oil squirt out of there?

If anyone knows... or indeed if anyone knows how to search for the part ...please help! I am runnin gon premix until then... it nearly cost me my bike!!

Thanks,
nik

Update:
After hobbling home , shifting became harder.
Once I got home went to drain the gearbox and the gear oil
came out blue - I.e. the two stroke oil is dumped in the gearbox. Judging from how much blasted out I dare say the gearbox was full of oil , and the leak I experience is coming from the oil filler plug .

I am stumped. Crank seals ?

Help!

seal on back of auto lube oil pump went out ??
dave

Thanks Dave.

Do you mean the gasket sitting between pump and left engine side?
Would that dump oil in the gearbox?

Thought the pump is a sealed unit..oil on one pipe and outtthe other. No?

Thanks,

Nik

the seal on the pump drive maybe

if its 2 smoker oil it has to come from some where

the 3 cylinder suzuki gt380 or 550 i forget which
was bad about leaking through the pump into the bottom end of engine
and ripping the piston off the rod when it started on the other piston

dave

Thank You Sir,
And by the looks of things my MZ too

That would explain why after priming and idling the engine with the pump pulley pulled the oil deliverypipe didn't move. Tell a lie. It would nmove after the engine was switched of. Slowly!

Guessing replace pump? Let me rip the bastard out will post piccies as it seems the problem not mentioned by members before.

Note: Gearboxes don't run too well with 2 litres of two stroke oil in them. Good job I don't need neutral

All th best,
Nik

Well I have an update...

After filling the bike with premix - I was convinced the 2T oil was coming from somewhere but...
I got home (bike was at work) so I got home. The shifting was sketchy and it was evident 'something weren't right'!
The gearbox was noticeably warm - which led me to drain the gearbox for signs of what had happened. When I removed the screw... the oil BLASTED out, filling my oil collection tank with a good two litres of two stroke oil .

Next, we got the pump off. And....



clearly there is an issue with the back of the pump..alas shouldn't there be a bit of metal that sticks out to e driven by the driveshaft..?
A thorough flush of the engine, with a heroic clunk revealed


The question is - what else am I missing? I suspect from the stress marks there most likely is a flat thingy that connects into the engine..but so far it has not been located.

Yup - waiting for payday to get a new pump - although I must admit I like being like an MZ druid, making things smoke, go and smell strange.

Does anyone know of anyone with a broken autolube shaft? My speedo claims 62k kms (about 40K miles) so I guess it is normal wear and tear, and me driving rather hamfistedly!!

Cheers all,
keep it MZ!

I've never seen or heard of that before, most likely a seized pump. Weird!

I don't think you’ve done anything to make that happen, just bad luck.

A similar thing happened to me once although there was no leak, while riding from Blyth to Alnwick (30~ quick miles) when about 15 miles into the journey the engine suddenly siezed up.

After cooling down it started off again and away we went for another couple, then it nipped up again, I checked everything I could, even removed the pump and there was nothing unusual to be seen. I reassembled and carried on this Nip-stop-go routine until I was basically just idling along country roads to my destination as anything more caused it to sieze.

Upon investigation (on the then GF's parents patio!) I pulled everything apart again and rotated the pump only to have the shaft come away in my hand!

The root cause (unfortunately for you probably) is the gearbox input bearing starting to fail. When you select a gear with the engine running the sudden drag on the clutch causes the large sprocket to move up and down (when viewed from the side). It makes light work of the pump shaft as it's hardened steel and doesn't take kindly to shearing forces.

You need to split the engine and look for the 'tongue' of the pump which is evidently missing, also replace that bearing while you're in there.

Sorry for the bad news!

Dave.

p.s. You're also missing the oil seal, seals against the shiny part of the broken pump shaft. That's relatively trivial though as it would be chewed up and spat out of the primary gears without causing much of an issue.

Dave.

Thanks Dave - you are /were spot on.. as the next of my posts suggests.
The bearing did go... and am in the process of rebuilding now.

I now.. know better

Meanwhile yes I did get a seal , as she used to leak all the time and look forward putting it all together!!

Thanks,
nik