MZ/MuZ Riders

Hey!

I just bought a 1983 TS125 about a week ago and thank god I found this forum!

Today, as I was on my way to do some food shopping, I started having problems with the bike. When I turned on the main lights the engine would just die out. Eventually it wouldn't even let me ride with the town lights. I still kept on going until the engine started loosing power and the bike just died out and wouldnt start again (I would have thought once the bike was going it'd be fine because of the dynamo) There is no spark either so even though I don't know much about motorbikes from what I've been reading it seems like the battery is flat. What's weird is that I tried starting it downhill in 2nd gear and it still died out. Because of the dynamo ,shouldn't it start in 2nd gear whether it has a working battery or not? Does this mean the problem is not just a flat battery?

I'm quite worried as you can imagine as I have no technical experience with bikes and I only just bought it a little while ago. I guess the next logical step is to charge the battery but your advice will be greatly appreciated!

test the battery some bikes will run without one some will not ...
if its been setting and not being used the battery may have gone bad
dave

Hi,
After you have charged the battery could you make a note of what the charging light is doing please, then let us know?
There is a useful technical guide and wiring diagram at this link

http://www.sweller.co.uk/mz/mz_maindex.html

Have a read of the "testing system components" section for your electrical system (12v or 6v). Have a go at doing some basic tests if you feel confident enough and have a multimeter (very useful to have) and post the results back here.

David.

Hey!

Thanks for your quick replies. I'm in the middle of reading through those links and looking at the electrical circuit.

Something happened before though. I went outside to see the bike and tried starting it, and it did. Also the lights were working fine and it went fine. Two minutes later as I was doing a test drive it died out. I turned off the lights, started it, and its when I put on the beam lights that it seems to short circuit the system and stop providing a spark because it just dies out. So it can't be a flat battery, it has to be some bad contact in the circuit right? I'll keep looking at your links and learn more about it. Thanks a lot for the help guys!

Jose

light switch ??? may have dirty or shorted contacts
also give all the wires with head lamp and tail lam a good look
some one may have cobbled some thing up
electrical on a used bike is a pain because you do not know
if the last fellow screwed something up from just a lack
of knowing how it works
dave

and show me a link to its wiring drawing when you find the correct one

Hey!

I've checked all the contacts and everything seems to be fine. Here's whats weird.
Normally the bike will start, after 30 seconds of riding it it will die out after which it will start but when turning on the lights at the ignition switch it cuts off. Eventually it doesn't even start. There was a point were to spark was being produced. No electricity, no light, no nothing. Took out the battery and just connected the cables to close the circuit. Dynamo is fine, condenser looks a bit burnt on the outside, covered in white stuff. What's weird is that a few hours later it will go back to having electricity and it will start up fine, but go through the whole cycle again of turning itself of after a few metes .... It's driving me nisane, tomorrow I'll try charging the battery up, although the bike should be starting without it, the dyanmo is sufficient.

Will let you know how it goes!

J

pardon my ignorance, but could there be an exposed wire that is only shorting out with engine running due to vibrations/discharging the battery,
and when they stop its back to harmless state?

condenser may be bad
and the spring on the points can cause funny running if its the original form the factory
and has set for years and lost its tension

had am old bmw it would start and run fine below 2500rpm but above that the points spring was weak
and it would miss fire it had set stored 13 years
dave

Hi,
Try this simple test. Get an electrical multimeter, set it a DCV and hold the contacts against the + and - on the battery. See what voltage you have.It should be around 6.2V - 6.4V.Start the bike and see if you are getting at least 6.4V across the battery. When reving the bike this should increase. If it does it means the charging system is working and more than likely your battery is knackered. You do need a good battery for these to run properly with lights on.
Now for the more difficult bits.
If you are not getting over 6V you have a problem with your charging system. Have you checked the two carbon brushes?
Another culprit could be the voltage regulator which is situated above the battery. Disconnect the battery and remove the cover. Check the settings on this as per the information on http://www.sweller.co.uk/mz/mz_maindex.html. With the cover off and the battery reconnected you should see movement on the points in here especially when you flick on and off the lights.
Check all the electrical connections are tight and clean.
Are the contact breaker points badly pitted? If they are it means that the condensor could be gone. You will see this if you start the bike in a dark room or at night and there is a extra large spark at the contact breaker points. GDMZ59

Hey,

thanks for all your advice, I'm trying to do what you guys are saying. It's quite fun because you learn so much doing research and reading Haynes manual.

Here's the test I did today:
- Checked the voltage across the battery with the engine off. Reading: 5.85 V
- Turned engine on and measured voltage at idle (5.9 V) and measure it whilst reving the bike (peak of 6.2V)
- At idle, turned lights on and voltage increased from 5.9 to 6.1. After a while (1 minute) voltage suddenly decreased to 2.5 - 3.5 V followed by the engine cutting off. Measured voltage across battery right after cutting off (3V) and after a few minutes bike started again with a voltage of 5.85 V.

After a few on and off, the bike wouldnt start at all. Although I'm sure if I go down now, it will, and the cycle will repeat itself. I still have more checking to do from what you've said above but I don't undestand what is going on. I'll now look at the regulator and check the dynamo and contact breakers as well. I'll keep you posted!

Thanks guys.

Jose