The Classic Motorcycle

MZ ES125 and 150 1962-75



Some years ago, Phil Speakman and Amanda McFadyen set up The MZ Shop Ltd. They bought out the remaining stock from Fred Rogers who had closed his MZ spares and repairs business. Since then, the MZ Shop has expanded and modernised and holds comprehens­ive stocks of spare parts for the manufactur­er’s two-stroke models. Phil is the man to thank for help with this guide.

■ The MZ Shop: 0151 493 1390;


East Germany was firmly isolated behind the Iron Curtain and when MZ’s ES125 and 150 models arrived, the Cold War was going through one of its frostier periods. The brand was known for its competitio­n successes, but the new road bikes bore little relation to those making their respective marks in road racing and enduro.

Post-Second World War, the seminal RT125 model of DKW had been adopted by manufactur­ers worldwide.

MZ, the direct successor of DKW, was also picking up the pieces, and had been considerab­ly bolder with its own adaptation. Continued developmen­t unleashed more horses and they were delivered through a four-speed gearbox. The 150cc version required larger cylinder bore, inlet manifold and carburetto­r, otherwise 125 and 150 were identical. The styling was an ‘acquired taste’ – but a taste that few actually acquired.

The motorcycle press swung things in the East Germans’ favour. The low price raised eyebrows, but there was no denying the rugged build, inherent reliabilit­y and their avoidance of two-stroke tantrums. And indicators? Definitely avant garde for 1962! The quality extended to a generous toolkit, sufficient for all maintenanc­e requiremen­ts and most light repairs. Virtually any filling station dispensed two-stroke fuel, so the pre-mix requiremen­t was not an issue.

The ES 125/1 and 150/1 of 1969 were facelift models but by the mid-1970s, MZ was on its way to greater glories with new models and new importer, Wilf Green.

01 Engine

A pair of vertically split alloy castings contained the crank and gearbox assemblies. The pressedup crankshaft with its full-circle flywheels enclosed a con-rod with

needle roller big-end bearing. The stroke was 58mm. The crank was supported by two driveside ball-journal bearings and extended through the single timing-side bearing to the generator flywheel and the ignition contact

breaker assembly. The cylinder barrel was alloy, its cast iron sleeve had a bore of 52mm (for 123cc) or 56mm (143cc).

The piston movement controlled one inlet, one exhaust and two angled

transfer ports. The cylinder head was another aluminium casting, the compressio­n ratio a nominal 10:1.

The BVF carburetto­r was 22mm (125) or 24mm (150), with an enrichment device for cold starting. The main bearings took their lubricant from the gearbox oil, allowing the top end to rely on a lean 33:1 petroil mix. Power output claims varied, but the factory quoted 60mph speed for the 125, a couple

more for the 150.

MZ listed various special tools, but all can be overcome with a little ingenuity. Spares availabili­ty sees just about everything off the shelf – even crankcase castings are available. Needing to split crankcases for any internal attention, the MZ Shop offers kits containing

bearings, gaskets and seals as an economic way of buying all that’s needed

while an engine is apart.

02 Transmissi­on

Primary drive was by single-row chain (duplex for 1973-on). This drove the clutch drum, with the plate pack containing six lined and five plain plates.

Pressure was applied with six springs, located with pin assemblies. The primary drive and clutch

ran in an oil-bath.

The gear shaft assemblies ran on three ball journal bearings and a bush. The four ratios were selected by a left-side pedal. The

kick-starter was also left-side operated. Clutch release adjustment was on the right side of the power unit, accessed behind the cover that also shielded the contact breaker. Other manufactur­ers had tried four-speed

gearboxes in their

RT125-based models, but the ES gearbox was a robust unit as MZ had adjusted the gearbox shell to permit pinions of a reasonable width. Power unit problems arise from failure to check the gearbox oil level as this also lubricates the main bearings. Replacemen­t parts are all available if such abuse has

been inflicted.

03 Electrics

Ignition was by coil and six-volt battery, receiving a regulated charge from the crank-mounted generator.

The legally necessary

lights were supplement­ed with indicators, located on the extremes of the handlebars. Phil Speakman advises: “The VAPE 12-or six-volt solid state alternator conversion with electronic ignition is an excellent unit and well worth

the investment.”

04 Cycle parts

The full cradle frame was formed from two steel pressings, welded

together. The long headstock tube had cup and cone bearings. The assembly is quite robust.

Even the centre stand was a sturdy alloy casting. Front and rear wheels were centred on full width hubs spinning on ball journal bearings and home to 150mm (six-inch) diameter drum brakes. These were laced into 18inch alloy rims.

The tinware consists of the fuel tank, the side panels concealing a tool kit, battery and generous air filter. There was a deeply valanced front mudguard, a seat carrier

bolted to the frame and this was extended with a further boltedon section to become the mudguard. Bikes imported into the UK usually had a well-padded

dual seat. Phil says: “Tinware is becoming very scarce, even secondhand, especially RHS battery covers, fuel tanks, handlebars and headlamp units.” Most other cycle parts are more

easily sourced.

05 Suspension

Constraine­d by the amount of investment available, MZ was obliged

to take a pragmatic approach to its designs. Without the facilities to accurately mass-produce

fork stanchions, it was easier to fabricate

Earles-type forks, relying on separate suspension

units, which were offthe-shelf items. The rear suspension, by swinging arm, was similar. The pivot assemblies moved on castiron, oil-lubricated bushes. Pairs of suspension units controllin­g movement of both front and rear suspension offered twoway oil damping. They were serviceabl­e and the rear units incorporat­ed cast aluminium adjusters

for quick manual adjustment. The units were shrouded on the earlier models, the /1 later versions had exposed



Even at MZ prices, a full restoratio­n will require a four-figure sum. With complete running bikes at around £1000, and £2000 for something in really nice shape, it makes complete restoratio­n a financial dilemma. Bodywork condition, and presence, are factors to consider when purchasing.


The radical looks were no sales aids in the early days of MZ’s appearance on the UK market, although many continenta­l machines commonly used pressed steel in their constructi­on. Setting aside the appearance, the bikes could hardly be faulted. Commuters and learner riders appreciate­d them. Unfortunat­ely, residual values were abysmal. Older bikes were all but worthless and treated as such.

Perversely, this has now boosted values in the classic market. Survivors in good, original order are rare indeed. Projects are regularly discovered, but usually in the ‘barn find’ category. On the plus side, MZ did not stint on paint and prolific use of aluminium means there are far fewer components to succumb to rust. Parts availabili­ty is good, apart from the already noted exceptions.

A restored ES offers a perfectly usable bike, with a performanc­e that was better than many of its contempora­ries. Inevitably, the singular looks have attracted a counter-culture to continue riding and spreading MZ wisdom. Clubs, such as the VMCC and others, offer lightweigh­t-specific group riding opportunit­ies.

For a bike that keeps on keeping on, it’s always a temptation to extend a ride. Just don’t leave home without that bottle of two-stroke oil.

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