New ETZ 250 rider here and some questions

[Blurredman]

Thank you for your images Puffs. They are quite informative but I am surprised you get so little mileage. Maybe I am just less harsh on the throttle and braking....?

I had a Heidenau K36 (3.5x18) on the rear of my ETZ300 for a few years and that lasted just less than 6k miles. It is likely it may or may not have lasted longer, it is only in recent times I am sure to use my tyre until the legal limit (1mm in my country for motorcycles - 1.6mm for cars however) so it is possible I have lost out a little in use of my tyres in the past relying on the wear indicator instead of using my own measurements. No longer will that be the case!


Klemmy: as Puffs has said I would look at the fuse box to make sure the fuses are making a connection. Possible the jolt has dislodged a fuse or made an already poor connection worse.
Can you verify that it charges or not with the voltage meter?
Also check the wires from/to the alternator to the rectifier and also the voltage regulator.

[klemmy]

I was at work today all day, so I couldnt do much investigeting about the problem. The thing is, that I drove on the bad road, with many potholes, so the speed was not high. Instantly after hit, indicator light came. I made about 6 km to home, without any other indication or problem.

Later I took off the cover and I found squashed brown wire, which goes on alternators right corner, but I dont know, what exactly is its purpose. This is my mistake, I was not careful enough, when I put the cover on, when I was looking if the Loctite did his work on the leaky plug next to neutral light switch. But that was before I ride the bike and it was about 50 km long ride, with no sign anything could be wrong, whatsoever. I cut the damaged wire part and connected it again with the clamp wire connector, very similar to one, that is on the wire of neutral light switch. I was looking forward and I saw one disconnected wire on the alternators down side, where 3 black wires are. I plugged it in I thought, I found the problem. No, the light is still on.

Every other wires are looking ok, so do fuses.

I have some hobby program multimeter and I will try to do some measurings tommorow.

Thank you very much for your support.

[klemmy]

I was meant to say "brown wire" not "brown wife" I hope, there will be no misunderstandings

[Puffs]

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[klemmy]

Quick update...I had cleaned some of contacts today and bike is charging and running just fine No warning light on, during running...Did a quick ride, few km around the block and everything is looking normal. So far, so good.

[Puffs]

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[Blurredman]

I've spent a lot of time in the past and still do, cleaning (wirewool or sandpaper) the spades and their respective connections, or reinforcing the connection to the spades with solder. I also find that if they are not too tight then slightly (!) crimp the spade connectors down a bit with pliers and they should be a tight connection when affixing onto the male counterpart.

As for your crushed wire- I wouldn't worry, that brown wire is the earth wire anyway, so being crushed (the the extent that it showed the copper core) wouldn't have done anything as the motor as a hole is obviously earthed too. Unless of course it cut through the copper core, but I doubt it. I've done this a few times in the past too.


But good you found that it now charges nicely

[klemmy]

Thank you very much for your advices!

Today I did a 50km ride to check, if everything is OK and so far, so good

BTW, I know, that there is a separate discussion about the spare part dealers, but is somebody here from poland? There is one delaer with used and new original DDR parts, but unfortunately there is no "english language option", even for me, coming from slavic speaking country, polish language is (almost) completely incomprehensible. So, google translate may help https://moto4fun.pl/

[Puffs]

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[klemmy]

There is also a man, who is doing a full restorations on MZ from Poland https://www.youtube.com/@michagajewski9409

I'm thinking about a new carb and electronic ignition sometime in the future...There is plenty informations out there on the forums, which makes all more or less confusing

On my bike is still original BVF 30n2-5, what could be good alternative? Any thougts on this https://www.classicbikehub.uk/Workshop/ ... wap_etz250

[Blurredman]

Hey Klemmy


There are many such people who do restorations, I find they are predominantly based in eastern europe mostly Poland, yes. The Polish love their MZ's just as anyone else.

There are a few things to consider I think when you pose such interests in components. The biggest for me is cost. But there's also, if there is any 'point', will the new item be worth it, short term, long term. Reliability? Etc.

I have myself toyed with the idea of a different carburettor or two in the past when I have been having problems, namely in my early days of messing with my MZ ETZ250, which of course also shares the same factory standard carburettor as yours. There is an MZ club I am a member of in the UK, and each month our particular region meets. And I see a lot of bikes with replacement carburettors. I don't know whether this is because their bike was purchased missing the carburettor, or they broke it, or it was worn or most likely they couldn't work out how to tune the carburettor properly. That's not to say that the basic BVF carbs are complicated- they certainly aren't. But in that regard this may also be a reason they are replaced - because there is potential for a smoother, torqueier ride with a new and 'complicated' carburettor. I haven't actually ridden one on any carburettor than the standard (my three MZ's have all their original carburettors) so I cannot say whether it is worth it from a point of performance, or fuel economy etc.

There are a few members on this forum however who have experimented, I know Puffs has tried replacement cheap copy production carburettor, but I have forgotten the outcome of whether there was any benefit or not of that. Maybe he can elucidate us.

And in terms of electrics, I think the three phase alternator on the MZ is very good, a lot of power and provides more than the bike needs by quite an excess, esspecially considering how the 6v generators MZ used to use are basically only just good 'enough' for the needs of the bike and no more with it's 60w output, as opposed to the 12v ones with their 180w.

Anyway, the generators are pretty robust too- i've only had one break on me and that was entirely my fault and my inability to double check things after wiring it up... I think general wear from distance travelled with obviously degrade them but when you reach huge miles I suppose you expect that possibility. I obviously don't know what type of riding you do, whether you commute, go on touring holidays, or just ride for a few miles on a sunny evening once in a while, but I don't actually think many people will wear down the components naturally, unless something odd goes wrong (stuck brush, something caught in the slip ring surface, damage from elsewhere etc).


And you don't necessarily mention which type of electronic ignition- are you talking about the full stator replacement arrangement, or a simple device that merely replaces the contact breakers? There is a huge price difference of course. I actually use a contactless ignition kit (£60 at the time) on my 251- but that was only because the crankshaft was out of balance and therefore the points were unable to by used properly. If that was not an issue, I wouldn't have bought my EI kit and would happily have used points forever more, as is the case with my two other MZ's. But alas, there is obviously one benefit (though there are downsides of course too like any thing), and that is you don't have to maintain the contact breaker, check for wear, adjust for wear, etc. The downsides are that you are relying on a black electronics box that you can't service, esspecially out in the middle of nowhere. For the most part, you can try and at least bodge contact breakers to work.... And actually- do the contact breakers really need that much looking after? No...



Well I hope I haven't talked too much (I have a lot of time to type when sat at my computer at work) - but these are my thoughts and others will be different. Again, I have also considered different carburettors, and DO have contactless ignition so it's not that I am trying to disuade your ideas but indeed I have at least in part have some experience, as do others on this forum whom I think should also discuss what they think of your proposals.

[Kruh]

On the carb:

I haven't tried a Mikuni, but I'm sure its a great choice if you can find a original one.
My experience is limited to Keihin PWK carbs, more specifically its replicas.
I've written more about it on this thread: viewtopic.php?f=20&t=10290
Almost 3 years now running the carb mentioned in the thread. No issues whatsoever. It wasn't too difficult to tune the mixture. The bike starts and perfoms great.
Sadly, my original carb was too worn out to be usable, so I never used it and therefore can't compare performance.
If I got another MZ with a worn carb, I would very likely go the same route. Unless I found a good deal on a original Dellorto, Mikuni or Keihin.


On the ignition:

For me, the switch to a modern electronic ignition system was a no brainer, because I had the original 6V system on my TS250 before. Recently, I also replaced the original 12V electronic ignition system on a ETZ250 with a more modern one. More specifically this one: http://www.wsk.audiobas.pl/sklep/zaplon ... azowe.html
But there a numerous other vendors selling basically the same ignition systems, which are based on the chinese GY6 alternators.
For me personally, these are a worthwhile upgrade. Like Blurredman says, you can't exactly service them on the side of the road. But they are less likely to need frequent servicing.
Because so many of them are based on GY6 components, stators (pickup included), coils and regulators are easy to come by in most shops and are cheap. If there is someting wrong parts are easily replaceable. If I go on a longer trip, I'll just take a spare stator and coil.
From experience, I've been using my ignition for 2 years now with absolutely no issues. I can't speak for it longer term, but I don't see there being any major problems any time soon.
Another thing I like about these is that the whole system is a bit more simplified. Perhaps its just in my mind that I understand the system better than the original rats nest of wires and components. Furthermore, I brought the component count down further by using a Derbi unit which contains both the CDI and coil in one, instead of the two being separate.
Another small benefit, is that this is an alternator with permanent magnets, which means the bike runs regardless of the condition of the battery.

Just a few of my thoughts and experience. One could easily argue againts a few of these points. But I just feel more comfortable with this ignition.

[Puffs]

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[Kruh]

I'm not sure about the others. But I can confirm that the GY6 ignitions offered for MZs, do not have an ignition curve. Rather, its fixed at one point.
Although, there is a large selection of CDI boxes you could pair with the GY6 ignition, with various ignition curves.
I have looked into getting another CDI for myself at one point. But a most of them fail to include a graph showing the ignition curve or atleast I haven't been able to find them. From the few I've seen, they tend to retard the ignition at a much later RPM than our MZs are capable of. Also with MZs being so low revving as they are, I wonder how much of a performance difference there even would be.

[Puffs]

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