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; www.themzshop.co.uk
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.
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.
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
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
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
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.