New ES250 Trophy Project!

[Puffs]

That looks quite adequate - but why stop painting there...!

[Blurredman]

One day I might paint it all, maybe.

[Puffs]

Beauty is in the eye of the beholder!

But back to the 0.5mm, I think you mentioned somewhere that it's quite common for these mounting tabs to break off. Again, that would then be metal fatigue, induced by vibration I'd guess. In that case, using a thinner grade steel might help & might actually be less susceptible to breaking? Depending on what it carries, resonance frequencies & so.

[Blurredman]

Some outlets provide the same weld on brackets for the battery tray but that's a different issue. The battery trays as traditionally they always do tend to rot from battery acid, but I think the original top bracket is fair thick for the task. It does seem to me rather a bit of a poor design maybe. But who am I to say, I am just one person- I can't account for how many times such an issue has occurred to other owners of these bikes- This particular machine might have been the result of an unfortunate slide, but what's more you can also account perhaps for thieves who don't take diligence in removing such covers to steal things such as batteries, as has happened to me in the past.

The 0.5mm VCR cover may indeed provide a bit more resistence to vibration, by absorption. Only time can tell- but as the bike stands as a 'toy' as it were at currently, it might be many many years for me to realise if my bracket will ever break off.

But as it stands, with a slap of paint on it, and a bit of dressing of the welds, you can hide all sorts of amateur sins!!

[Puffs]

Again true. And the angle grinder is our friend. My welding looks quite poor, but after a bit of re-work (my time is cheap nowadays) it looks a lot better.

Battery acid: a reason for using an AGM battery - no leaks.

[Blurredman]

I've not been doing too much to this bike what with lots of other things to do, but there were a few problems I have had and some which I do believe I have finally resolved..

- Rear wheel pulsing under braking.
Been an issue since bike first put in use. Of course both drums were full of rust on the linings, and with other vehicles in the past which have also had this problem, simply using the brakes/bike eventually rubs all that rust away. It can take a while sometimes as the rust can be quite deep, but so far doing this I've never had a problem with the rust eventually being rubbed away and still having a true brake.. That's what I thought until recently anyway because after 750 miles the rear brake still had rust in it and pulsed (front was all rubbed clear). However, clearing out the rust dust and giving it a good clean internally, and then putting all back together tightening the main spindle whilst the brake was being applied seems to have got rid of the pusling. There is some rust evidenced still inside the drum, but the brake itself is now linear as it should be.

- Recent misfire.
On the way back from one of my recent trips to the local (well 55 miles away) MZ club meets, the bike misfired soon before arriving at the destination. I changed the spark plug when I got there and started the bike and all seemed fine again, except the same thing happned when I started on home. Bike was fine to ride at 10mph + and happy enough but low RPM/speed had it bucking as it was mis-firing. I waited a few days but put the original spark plug back in and it ran perfectly fine (or, idled fine at least). I was planning to replace the main ignition feed from the switch to the coil + anyway as I wondered whether that was an issue with my loping idle. As previously mentioned, I had to put a new section of wire between brake bulb + and coil + otherwise the brake light wouldn't illuminate except at high RPM which is odd. What is interesting is that the same wire that feeds the brake bulb is that same ignition wire to the coil from the ignition switch. So it could be connected. Maybe the whole wire is 'bad', so I did replace that 2nd section last night. The bike did seem to start and idle much nicer despite not being run for a few weeks (though the recent warm weather helps I suppose). So there could be something in that.

But something interesting occured after doing the above- charging: I decided to check the charging. Previously the bike didn't seem to charge above 6.3v when the lights were turned on, but I happened to give it a quick look after laying this new cable and found the bike charging with the lights on at a much better 6.7-6.8v when being reved. I'm much happier about that obviously. There could be significant voltage loss in that ignition wire???? The ends of the wire didn't seem in bad condition, if all but a little white crusting occuring. But it is possible the whole wire is an issue (for example, in the section that goes to brake light where no Voltage was being recorded at all at low RPM), so some significant issues maybe. Though I did a resistence check and there didn't seem anything wrong with that simple test, on the face of it. I am tempted to remove (or disconnect it at least) that new wire and see whether that did change the charge rate or whether that had snuck up on me during the last few hundred miles and rectified itself. It would be nice to have a concrete answer on that.

[DAVID THOMPSON]

6 volt systems stink
I have had 3 BMWs r 26/r27
they have all went on to others owners
because of the 6volt system
nice bikes but the 6volt systems stinks

[Puffs]

I politely disagree Dave. It is true that at 6V you need twice the current to reach the same power as at 12V, which can be an issue for spade connections, but on the other hand, 6V might be less sensitive to leaks due to humidity. In modern days, the power issue may be resolved by LEDs, while the ignition can be independent of the battery voltage. I know it isn't in conventional systems, but the 6V conventional battery/coil/points system has electrically always worked flawless in my Jawa 634. And lastly: 6V is often original, FWIW.

- Rear wheel pulsing under braking: tighten while applying the brake is a tip worth trying! Apparently there is some clearance between the axle (shaft/spindle) and the hole in the brake back plate, and tightening it when the shoes are expanded to the lining in the drum would centralise & position the plate properly wrt the drum. Edit: Thinking more about it, I don't actually see how an offset can result in a pulsating feeling. Poor alignment will result in braking less good (due to poorer contact on 1 side), but if the brake lining inside the hub rotates nicely circular around the axle (or any central point), there shouldn't be any pulsing. Why should there? Uneven rust? Or hub deformed due to uneven spoke tension (as I had).

- Ignition/charging: 6.75V with the lights on is fine. It could be slightly more, but possibly this is what the regulator was designed for.
But: is it possible the wiring is (or was) incorrect? Things like 'the brake light wouldn't illuminate except at high RPM' sound very odd & maybe indicative of incorrect wiring somewhere. And indeed, the currents in a 6V system are bigger, so the wires must be in good nick & things like 'white crusting' are not good (corrosion? poor contact?).

Once again, invite Dirk Gently for tea.

[dave47]

Apart from the technical aspects, the annoying thing about 6v electrics is that it's obsolete, and hence hard to find accessories such as phone chargers, heated grips or aftermarket switches.

[Puffs]

Heated grips should still work on 6V, only dissipating half as much heat. But I wouldn't know, never had (or felt the need for) any.

True, there probably are no off-the-shelf USB outlets/phone chargers for 6V (though there might be, if you search). For me that's not an issue, and none of my 12V bikes have one either. USB outlets in vehicles are quite a recent thing, and for me totally irrelevant. Yet, if so desired, a 6V one can be quite easily made, see https://www.youtube.com/watch?v=oh5Nsa53HWw & others.

Switches should work on 6V even better than on 12V - lower chance on bridging/arcing! And LED bulbs are available for 6V too.

For me, the biggest issue with 6V is the higher current, requiring better contact & continuity. Corrosion, causing poor contact, can be an issue, and I think this is what Dave is referring to. Yes, it can give problems. Like in a fuse box, which has actually given me problems on 12V. Neither of my two 6V bikes ever gave me problems like that though (and actually neither seem to have much in the way of a fuse 'box').

But to each his own, and I appreciate that it is hard to find accessories for 6V. Ah well, an old bike is a choice...
Yet particularly the MZ 2t's can be converted to 12V very easily, though at a price.

[Blurredman]

I honestly think 6v gets a bit of hate for reasons which may be unneccesary.

It is true, they can have more limiting factors of perfect operation due to unperfect wiring or bad maintenance, but 6v was used for decades upon decades and right up until relatively recently on mainline machines for the public, specifically the Japanese loved 6v for a very long time.


I don't necessarily have too much of a concern about bulbs and stuff myself. Infact the bigger concern when it comes to the Trophy is the fact the rear light bulbs are both festoon (indicators too if they're fitted) bulbs, which is a bit more complicated to find in 6v form sure, but possible. Moreover, you could get around these limitations by using a 12v bulb anyway, but with half the wattage if available at a pinch.


Two of my bikes are 6v (one is the Trophy) and I really don't have a problem with their systems per se. One is a 1979 Suzuki TS185ER, which is actually very interesting as it is a self exciting machine with contactless ignition and an advance curve. The only downside to the system is 25w headlamp, but you ride as fast as you can see... If you get home late and wet, you get home still, just late and wet. And not on the floor with a broken leg because you couldn't see. But there's the point too, 6v isn't a limitation there, the limitation is the wattage provided by the system. 6V 50w headlamp is the same as a 12v 50w headlamp ...


But back to buying extras. I think is's possible things could still work with the 6v bikes, the problem is their output, which considering this MZ is 60w generator which seems to only just cover it's load anyway (typical load being 40w+4w+1.2w+1.2w+5w means 9w is all that is left when the situation calls for lights to be used. I'm not sure how much of that will be used for ignition but it's going to be a great deal of it. So it's capable to convert USB chargers (or cigarette lighters), or heated grips the charging system might not be capable simply by design limitation.

[Puffs]

My apologies, I f'ed up again. I said "Heated grips should still work on 6V, only dissipating half as much heat.", but that's not true. At 6V, the current is half of that at 12V (neglecting changes in R due to temperature change), and as the voltage is also half, the power (P = U x I) at 6V is only 25% of that at 12V.

Btw, some searching taught me heated grips typically take 30-40W (per pair), so there's another choice: light or warm hands...

[dave47]

Yes, heated grips would definitely be too much for the MZ dynamo, but surely a phone charger/USB port is essential nowadays, especially if you go touring. I also use my phone as a satnav on occasions, and a power supply would be useful. I have looked into this in the past, and was aware of the idea of using a diode to drop the battery voltage by one volt, but this assumes competence with a soldering iron which I don't have. Also its not exactly sophisticated voltage regulation, and while it would work on a lantern battery, it might not cope with the voltage variations and spikes of motorbike electrics. But perhaps I am looking for difficulties that don't exist.

The switchgear issue, for me, is that I hate the original MZ 6 volt system with the indicator switch as a separate add-on at the RHS, and wish to replace it with a standard LHS Japanese type handlebar switch. There are plenty of these available, made in China, but only suitable for 12V systems. Their wiring and internal components are made to a price and will not cope with the higher currents of 6V electrics without the dangers of overheating or voltage drop. The few 6V switches found at breakers are likely to be very old and worn out. Of course, somebody here might know of a source, but I have not found one.

But as you say, this is just part of owning an old bike and can be solved now, thanks to Vape and Tezet.

[Blurredman]

Some interesting comments following up on voltage and wattage output guys.



But, for me: Back to the bike. This afternoon I took the bike for a ride. I recently rode it yesterday and had no issues other than it did stall after getting back home, but with this in mind, I though i'd need to take the 'new ignition wire' test further.

I took my multimeter with me and varied between lights on and lights off whilst on my ride. And essentially I have two comments:

1) The bike actually charges at a max of 7.3v at peak with the lights on. A big high actually, but it rarely got above 7.1-7.2v and seemed to correct itself fairly quickly so... fine!

2) With the lights on, the bike mis-fires and stalls at idle. With the lights off it seems reluctant to stall- it stays running.


I got home and checked the coil with my hand for heat test and although luke warm (as I suppose they will always be). I don't think the coil is at fault as the bike runs.. A typical coil fault is a very warm/hot coil and a bike that won't start for a few minutes after cooling off. I did change the spark plug whilst out and that didn't fix anything.

So, with coil (likely) fine, and the bike charges happily now, i'm thinking of other ideas why the bike mis-fires when the lights are on... Would a poor consenser/capacitor or points or the main resistor cause this?? I wouldn't think points would do this in themselves, but although resistences checked out okay after putting the bike back together (not to say they may not have failed since) is it possible the stator has degraded? Points aren't particularly burnt or arced/pitted so I don't 'think' there is an issue there.

Thoughts?????

I've been looking at this website:
https://pic.mz-forum.com/lothar/Elektri ... ektrik.htm

And specifically the section "V.1.2 Voltage drops in the vehicle electrical system" (ctrl+F as there are no pages), ant it does talk about specific voltage drops in various junction places throughout the system which I could also test for. I am using the original fuse type- it could be possible for example that there is too much voltage drop in the simple friction held fuse for one example...

[dave47]

Thanks for that useful link, Blurredman. Have you seen section V4.1 - Does this describe your case?