MZ ETZ 125 Fault Location procedure

[HENRY]

What does 'Body contact in the rotor' mean? I'm going through the manual for fault location.

[Puffs]

I'm guessing continuity between a winding & the rotor body?

Windings like that have a rather thin isolating coating, which can wear through due to vibration.

What resistivity do you see between winding & rotor body?

[HENRY]

I have completely no idea to that question!
I have briefly followed the MZ Repair Manual's procedure using a test light for the rotor and stator and the results both state that they are interrupted or have body contact.
My bike has been off the road for a while and I will continue to try and get it to start again - the spark from the plug has been a weak yellow one for as long as I remember.

Does anyone with a ETZ manage to get a strong blue spark?

[Puffs]

I think the spark on my '89 ETZ251 is pretty good.

But I'm confused: in the standard electrical system, rotor & stator are part of the alternator (=generator), which generates the power to charge the battery. They don't actually have much to do with the ignition. Even without alternator, the ignition should still work fine, as long as your battery still has charge. Of course if your generator doesn't work, you battery will discharge with use: it costs power to charge your ignition coil, and using lights will drain the battery even more. What I'm saying is: if your problem is that the bike doesn't start, first check the battery voltage (with a multimeter across the battery poles, for a '87 ETZ typically 12V or more), and if you have a proper voltage, I'd first look at the ignition for any fault, not at the alternator.

[HENRY]

I'm still slowly getting the bike back together - I will try and focus on all of the ignition area.
That's great, thanks.

- - What would you be particularly looking something at in the ignition area and would this include the ignition switch as well?

Do I take it you still have the mechanical regulator, rectifier, fusebox and lastly original wiring and terminals all fitted?

[Puffs]

Yes Paul, the electrical system is entirely standard on my ETZ, though I have replaced a few wear parts over the years (spark plug, carbon brushes, battery). But the mechanical regulator, rectifier, fusebox and lastly original wiring and terminals are all still original, and this bike has endured some serious use. Particularly due to many years of year-round commuting use in Scotland, the regulator & fusebox have had some corrosion issues, but I managed to clean those away, and both are still the originals.

After a long period of not being used, suggest the following:
- check/charge/replace the battery
- have a look at your air filter
- clean, re-set & lube the contact breakers
- clean & adjust the spark plug
- make sure you have 2T oil in your oil tank, and gear oil in the gearbox
- drain the float bowl, clean the carburettor (just turn it 90° & look at the main jet), fresh fuel in the fuel tank
- check for leaks (sometimes rubber perishes)
- ride the thing, making sure you have smoke when you start it

Of course the bike might have been put aside at the time because it had an issue. Then that it will still have, and it still needs to be fixed.

To answer you question, for ignition issues look at ftp://blurredmanswebsite.ddns.net/Vehic ... es/081.jpg, kindly provided by member Blurredman. The ignition switch has never given me any hassle (do you see lights on the dashboard when you switch the ignition on?).

It might of course be something else than ignition, like stale fuel (with the more volatile components evaporated & gone you're left with something like diesel).

[HENRY]

I appreciate your time, thanks.