etz 125 project- hot wires?

[speargun]

Dear Riders

I am brand new to the forum and have recently got my hands on a few boxes of bits, most of which is a 1986 mz etz 125 d reg. I have spent the last 12 years on a 50cc vespa scooter (sorry!) and thought this project would be a good next step for me. My mechanical abilities are remedial at best- I rate myself at about 3 spanners from the haynes manual key and am looking for my fourth with this bike.

To date I have been cleaning and poking things into a rough form, the engine looks like it was complete (prior to the fiddling) and the carb has now been tinkered with so will probably need a standard reset. The wiring and electric however, this is a box of grotty chopped spaghetti and few old components off Sputnik 2. Its very possible I am missing some pieces even if the ones I have are in working order.

The list of things to do seems long and daunting, but first steps would seem to me to wire the engine to see if it runs at all? Does anyone know how to do this, IE: Which (what color) wire runs from the stator (or better yet, out of the engine casing) to the coil and or anything else so that I can run the engine without a battery or the rest of the harness (which I will probably have to make once I know that the engine runs)

I have had a look at the wiring diagrams and am not having a great deal of luck deciphering them. I can try to post photos if this would help.

The rest of the bike seems to be mostly there (no tank or seat, but I have bodged alternatives) Wheels and tyres seem okay etc. I would like to get this back on the road as a runner with the least amount of financial input. Any tips, points, tricks, advice, or help would be greatly appreciated

many thanks

Speargun

[DAVID THOMPSON]

tell us where your city is located and some one may volunteer to get you started in the right direction

starting off with a box of parts is the hard way

[arry_b]

You'll need a 12v battery, the two stroke bikes don't run without one.

For a temporary lash up, connect the battery negative to the engine somewhere. Then run a cable from the battery positive to the coil, and a wire from the coil to the points. That'll provide you with a spark, and you'll be able to try starting the engine.

Don't leave the battery connected with the engine stopped and the points closed, or you'll fry the coil. They don't withstand that treatment for long.

[therealche]

The proper MZ wiring diagram is a doddle to follow. Get it printed out A3 and laminated to preserve it from oily fingers

http://www.mz.cx/technik/elektrik/schaltplan-12v-l.jpg

[speargun]

Thank you all for the very helpful input, I really do appreciate it.

David, I live in New cross gate, south east London uk, its really lovely. Had my scooter broken into or stolen five times last year, only twice so far this year. I do use locks and chains but the little darlings around here just like smashing stuff up for fun more than anything else.

I would love any extra help from a volunteer or 10 but I am really happy tinkering away at the moment. The mechanics course at http://www.dansmc.com that you have sent through has been good reading and I feel like I am making micro incremental progress.

therealche thanks for the vote of confidence in the wiring diagram doddle department, regrettably it looks like a gorgons head to me and instills a certain amount of fear of the unknown, nicely blended with fear of electrical component fry up. So far I have found-

http://www.colorado.edu/physics/Educati ... iring.html

good for simple wiring techniques and

http://www.bikeexif.com/motorcycle-wiring

for a basic understanding of how to make some initial fist steps

arry-b your lash up system has been really effective- thank you very kindly- it is similar to the steps 1,4,7,9 in the JOE TESSITORE article on bikeexif. I have had a wild swing at that enterprise and come up with- no spark. Surprise! Surprise!

Sooooooo.......

The first thing I did was- go out shoppin'! After a very brief youtube surf on the theme, I marched wholeheartedly to the electronics shop and bought a transistor and a resistor so that I could start some micro resistance measurements on a collection of wires I have scavenged, using a diy four wire tester.

wires

With the new components; I half baked a very generous serving of what I call palaver cake, which in hindsight has too bitter an after taste to be palatable; but is still hanging around as a reminder of how efficiently can derail a project if I don't stay on target.

palaver cake

Staring at Medusa's face http://www.mz.cx/technik/elektrik/schaltplan-12v-l.jpg a little longer I am slowly translating what I have in the box, with what is illustrated on the diagram. It's now evident that several disconnected electrical engineers have been stiring at that box and that the existant loom on my engine doesn't correlate with factory settings either.

The Wat Yong (registered trademark) ignition coil from this box is reading 6.0 ohms on the primary coil and 10 ohms k on the secondary coil, I can't find any specs to cross reference this against for etz 125, but from what I have read so far- I think I have toasted it or someone else got there first. Does anyone know what is the right ~amount in Ohms for this system?

I have won an ebay auction on a missing regulator which will need testing, and the rectifier is giving some resistance readings, again does anyone have access to information on the proper resistance readings for these parts in this system?

Regarding the wiring diagram. Beneath the inscription "12 volt"- is this the rear brake light switch? And at the end of the blue wire- is this the "neutral gear" sensor? If no, could anyone set me straight please? I have tried to add a couple of photos as a test run; because I have a few interesting components that are not in the diagram that might need identifying.

Again, thank you very much for the help

cheers

Speargun

[DAVID THOMPSON]

when putting spades on wires i am a fan of solder and shrink tube

not crimping
with solder they can be removed and reused when you have ran out of them
in the we hours of the night or in the back country 100 miles from the house

dave

[therealche]

The Wat Yong (registered trademark) ignition coil from this box is reading 6.0 ohms on the primary coil and 10 ohms k on the secondary coil, I can't find any specs to cross reference this against for etz 125, but from what I have read so far- I think I have toasted it or someone else got there first. Does anyone know what is the right ~amount in Ohms for this system?

6 ohm for the primary and 10K for the secondary sounds OK to me

I have won an ebay auction on a missing regulator which will need testing, and the rectifier is giving some resistance readings, again does anyone have access to information on the proper resistance readings for these parts in this system?

Cant lay my hands on my factory manual, I will get back to you. However the rectifier is very reliable

Regarding the wiring diagram. Beneath the inscription "12 volt"- is this the rear brake light switch?

Yes


And at the end of the blue wire- is this the "neutral gear" sensor?

Yes

Don't be overwhelmed by the wiring diagram. Just take one wire at a time and trace it through. For example the blue wire goes from the neutral switch, to the multiblock ( A common source of problems, make sure the blades are clean) then via a second block to the neutral light .

[speargun]

Lash up II the saga continues

Thank you very much for the fantastic advice

Its really encouraging.

when putting spades on wires i am a fan of solder and shrink tube

Dave are you suggesting that drilled out and soldered- recycled connection spades, insulated with electrical tape might not only save money but also have potential to work effectively? I don't want to put words into your mouth, its just that you have got me thinking.

I would enjoy the challenge if you think there is potential and would definitely appreciate the saving.

therealche- that's great news about Wat Yong (How could I have ever doubted the quality?), the new/old rectifier has arrived so it would be great to cross reference the recommended resistance measurements with what I am getting. Thanks for the help- awesome!

Having removed the coil, ht lead and plug from the no spark problem I have moved on to the points and condenser. This is all new territory for me and I am not particulary confident that I am measuring these devices properly, however, I have attached the meter to the head (+) and the body (-) of the condenser. The Ohms readings mean nothing to me unfortunately. When the meter is at 200 I get a reading of 8.4-8.5 and when it is at 200K I get a reading of 4.1-3.6 posting.php?mode=reply&f=19&t=8107#

I was under the impression that when I kicked the engine over something dramatic should happen to these measurements. Nothing to report on that front. Any feedback on this would be really handy.

I read somewhere on the archives that the points gap should be 0.020. The points gap on my engine is considerably larger and there is no spark between the points when the engine is kicked over. I suspect the points and timing will need addressing during the build, however is this issue crucial for spark?

Again - Any input or response to this post would be amazing, thank you very much!

cheers

speargun

[DAVID THOMPSON]

heat spade while holding with a pair of pliers

hit on vice spade hole should be free of solder if you got it hot enough

and use shrink fit tubing always never tape

and after being poor for 70 years doing things on the cheap has become a habit