MZ/MuZ Riders

Can any of you electrical boffins help throw some light on this problem I have, every time I connect the black to the black from the HT coil and turn the ignition on it blows the fuse, I thought I had it solved when I discovered bare wires in a rear indicator, I even disconnected all rear lamp and indicators, also the dip/main and cut out in case they were to ground. I have fitted a solid-state regulator and filled the instructions of joining wire 61 and DF+ leaving D- empty, I am out of fuses now and ripping my hair out, any suggestions are appreciated.

Shorted out coil?

As I suggested run a temprary wire from battery +ve to coil, other side of coil to points via fuse if you like.

If the fuse still blows then the coil is shorting out.

From what you say it sounds like the coil is shorting.

Do you have a multi meter, if so check the resistance of the coil pimary? - something like 2 ohms for a 6v coil and 3,5 ohms for a 12 volt coil or therabouts.

Andy, A couple of mof days ago I did a resistance test on the coil, I got a reading but it was very low and I was unsure as to what I should be getting. I will be in like a flash in the morning to test the bugger, thanks mate I really never suspected the coil.

Good luck Sid - sometimes it's the things we assume are working ok are the source of the problem.

Yes the resistance will be low in the order of ohms as I said, but you also need to check that the primary winding is not shorting to the can so check both sides of the coil primary to see if it is shorting to the can.

Let us know how you get on.

Puffs - yes I agree that measuring low resistances with a household meter is not easy. I am lucky enough to have access to an ex work Fluke Multimeter and a decent set of probes.

It may be easier to simply just wire the coil with some seperate wires if your multimeter is not up to it.

No doubt that Sid will report in later today

Andy, you are correct the report goes as follows, I removed the coil (I actually ordered a new one anyway it's in the post) but I removed the coil and did an ohms test it read 3.4, but I never rely on resistance readings, I thought with nothing going to or from the coil I will replace the fuse and see, well it blew instantly, I then removed all the wires from the new solid-state regulator, replaced the fuse and wham another flippin' fuse, it seems that whilst that black wire that emerges from the inline connector and is linked to the black to the coil is connected up to the ignition switch, then the fuses blow, there must be a straight short somewhere, but being shit on electrics I don't know where to begin, I know why the bloke sold it now, surely there can't be much to it....help..................

Sid - it sounds like the issue is with that black wire.

Reading what you say, you have taken both the coil and regulator out of the circuit, so it can only be the "black wire".

3.4 ohms is probably about right for a 12v coil.

Easy to confirm if coil is good or not.

Remove ALL wires to the coil except the HT lead to the plug.

1. Run a wire to one side of the primary of the coil - via a fuse to the battery +ve.
2. Run another wire from the other side of the coil to the points.
3. Make sure that the can of the coil is grounded to the chassis.
4. Make sure that battery -ve is grounded to the chassis.

If the fuse does not blow, kicking the bike should produce a spark, if it does not, the coil is knackered.

Wiring wise, it sounds like you need to check it all out, it is teedious but you have the diagram posted earlier so I reckon you are going to have to roll up your sleeves and get stuck in.

I know the wiring is not that easy to follow, the ETZ that I used to have had some issues when I bought and spent a lot of time sorting it out - keep telling yourself it is worth it in the long run.

My problem is my eyesight is a bit dodgy and I can't see any numbers on the ignition switch, how do you remove it from the headlamp? and does anyone have a drawing of one showing the numbers, also going back to my drawing a few posts back, what does that black wire do? I think it finally goes to the horn, I am asking because when I got the bike, that wire had been taken out, and now I reinstated it, it blows the fuse, I took the wires off the horn to no avail, I am just wondering, if I myself take the black out what am I losing? and maybe I can get the bike to run and have lights?? does anyone have any better suggestions.

As far as I see you did not tell us what bike you have.....

It seems to be a 6V MZ, but which one ?

Sorry, it's a 1974 TS 250 and it is still on 6 volt but the past owner put a form of electronic ignition on which seems to have caused some problems

Yes I did that and I got a spark, I have 2 condensers and both are OK, but when I put everything back so that the charging circuit works then it all goes tits up? later today I am taking that black wire out, I think it is number 15 on the switch in the headlamp and it also goes to the charging indicator bulb, which strangely enough went pop the first time I connected a battery up, it also appears to go to the flasher relay, so I am sure that wire is required.

Where do you live? I wonder if there is anyone who lives close who might be able to help you?