Sunday, June 13, 2021

New project - 1954 Berini M13 and BSA Bicycle

Because I like nothing more than having many projects on the go at the same time, I've picked up a Berini M13 autocycle motor, mounted on a 1930s BSA bicycle. 

The BSA is in very good condition and only needs a little clean up. I have decided however to replace the racing handle bars as I find it quite uncomfortable to be leaning forward while riding. I'm also going to fit hand brakes as the rear brake really doesn't provide enough stopping power.

I tried turning the racing bars around to get a feel for a more comfortable riding position.

Now the Berini. Autocycles were a popular accessory appearing in the 1920s that enabled a simple bicycle to become powered. DKW made its name originally with the 'Das Klein Wunder' Hifsmotor, a clip on bicycle engine in 1919. The DKW Hifsmotor was clipped over the rear wheel and provided its drive through a belt to the wheel hub.

I mention the DKW Hilfsmotor as the Berini M13 is it's cousin. In the chaos of the post-war period, one of DKW's motorcycle engineers, Bernhard Neumann, arrived in Holland in 1948 looking for work with a set of DKW motorcycle plans in his pocket. In partnership with two Dutch engineers, he developed a new version of the Hilfsmotor, but after trials they decided to simplify the engine and make it front mounted. This became the 32cc Berini M13.

The engine is extremely simple. It is mounted to the bicycle frame and is suspended slightly above the front wheel by a spring loaded lever. With the ignition switched on, fuel in the egg-shaped petrol tank, the rider simply pedals along as normal and when the appropriate speed is reach, the engine is dropped down into contact with the wheel, and friction from on the roller drive on the wheel fires the engine and you chug away at a blistering 10-15 kph. Something else to keep me busy!

Dutch Berini club

Owners manual in English (translation from Dutch):

Berini M13 Operating Instructions (English)

The Berini M13 bicycle motor has been designed by experienced two-stroke specialists with many years of international reputation in the field and has delivered convincing proof in practice of reliability, reliability and economy by tens of thousands of enthusiastic Berini riders.

The Berini M13 is characterized by its simplicity and by its ultra-modern two-stroke construction, while in addition, its harmonious appearance is a feast for the eyes. The external parts of the Berini M13 are well protected against the penetration of water, dust and dirt, while still being conveniently located and easily accessible.

The engine works according to the reverse scavenging system (flat piston and two overflow ports) and has a rotating inlet valve driven directly by the crankshaft. Due to this construction, very high efficiency is obtained while maintaining a low weight and size of the engine.

The crankshaft is journaled in three places with precision ball bearing races, while the big-end is equipped with a roller bearing with cage.

All parts are made of carefully selected materials, while both the carburettor and the ignition are selected from the best instrument makers.

An ingenious invention has made it possible to disconnect the drive from the left side handlebar lever at any time, even while driving. This also considerably simplifies starting and with this manoeuvrability makes the Berini M13 an unprecedentedly safe bicycle assistance engine.

All engines are assembled by us with great precision and thoroughly tested on the test bench before they are delivered.

A nationwide organization of Berini Agents, who have special tools and technicians instructed by us, ensures effective services is available to all Berini riders.

As with any bicycle motorcycle, some necessary maintenance work is required for the Berini M13 to ensure continued trouble-free use. It is therefore important that the operating instructions are followed carefully.

The bicycle of the Complete Berini M13

Much attention has been paid to the smooth running and good steering of the bicycle. The frame is made of seamless drawn steel tube and is distinguished by its rigidity, while the entire construction is designed to achieve the greatest possible strength and good lay-out. The modern frame makes the Berini M13 suitable for both men and women. The bicycle is equipped with two independently working brakes, a powerful drum brake in the front wheel and a Beckson brake hub in the rear wheel. The maintenance of the drum brake is limited to lubricating the pivot points from time to time with a few drops of not too thin oil. In order to maintain maximum braking force, stretching and slackening of the brake cable over time can be rectified by means of the cable adjustment screw located on the brake itself. The Beckson back pedals also require little maintenance but must be generously lubricated and adjusted once a month (about every 1000 km). It is recommended to leave the latter to an official Berini agent.

The Berini M13 engine can be mounted on any bicycle in a short time, without having to make radical changes to the bicycle. The assembly must be carried out exclusively by, or under the supervision of accredited Berini agents, who have the necessary professional knowledge, experience and special tools to correctly mount the Berini M13 on a bicycle for the best traction and ensure a long service life of the motor and bicycle.

By combining the Berini M13 and your bicycle, you have now obtained a truly ideal moped, which will provide you with loyal service for many years, provided you pay the necessary care and attention to the maintenance of both.

Packed with every Berini M13 is an envelope including the warranty certificate and an agent list. The warranty certificate, bearing the same number as the engine, must be completed in full and clearly legible in the presence of the supplier, after which the right half must be sent to us within 48 hours.

In case the supplier of your Berini M13 should not be an official Berini agent, it is important that all future service and repairs are performed by an official Berini agent so as not to void your warranty. Please consult the agent list supplied with the warranty certificate.

We cannot be held liable for any issues if the Berini M13 has repaired by non-official agents.

We recommend you use the special Berini tire on your bicycle, which is more resistant to wear and has a much longer life than a regular bicycle tire.

Needless to say, the life and reliability of the engine depends on the use of first-class lubricating oils. It is recommended to use a special two-stroke oil of a 1st class brand, with an SAE value of 30 or 40. This oil must be mixed with petrol in the ratio 1:25.

It is of the utmost importance to observe this mixing ratio accurately. The following precautions also apply:
1. The fuel must be absolutely clean;
2. The petrol and oil must always be mixed well in a separate container (shake!);
3. When filling the tank, always use a funnel with a fine sieve. Oil and petrol should never be added to the tank separately.

The fuel cap also serves as an oil measure, which accurately gives the correct amount to be mixed with 1 litre of petrol. The tank capacity is 1 1/4 litre.


Starting the engine
1. Open the fuel tap. The valve has two positions: - lever in longitudinal direction of the valve = open. Lever downwards = closed.
2. There is a gas lever on the right side of the handlebar, which operates the automatic choke at the same time. By moving this lever down and to the right (i.e., past the stop) a separate starting nozzle is opened in the carburetor, which supplies an extra amount of fuel, necessary for starting the cold engine.
3. Start riding the bicycle using the pedals until a speed of approximately 10-12 km/h is reached. The handle on the left handlebar (the clutch handle) is fully retracted. The clutch is kept retracted by a pawl on the handle.
4. After sufficient speed is achieved by pedaling, the clutch handle is retracted slightly and the pawl is pressed at the same time. this allows the handle to move down. It is advisable not to do this too slowly, as the sudden friction of the engine roller with the front tire starts the engine.
5. Once the engine is running, the gas lever is turned to the left. This deactivates the automatic choke and 'accelerates' in the normal way. Don’t give too much gas to start.
6. After this, continue pedaling until the motor is running sufficiently to take over. If the temperature is low the engine may tend to stall. If so, the gas lever should be turned back to the starting position (down and to the right) and the procedure above is repeated.
7. When running, the speed is then regulated by means of the gas lever.
8. Important: It is unnecessary to use the starter jet when the engine is hot.

To stop
To slow down while driving, the gas lever is turned down as required so that the engine receives less gas and thus slows down. If you want to bring the bicycle to a complete stop, turn off the gas supply completely, then pull in the clutch and use the brakes to stop.

Never stop the bike with the engine running and engaged.

Always close the fuel tap when putting your bicycle away.

Never let the roller slip on the belt!

Running in
During the first 300 km running in, do not exceed a speed of 20 km/h. Special care must be taken not to run the engine at a constant speed, but adjust the gas lever regularly. That is to say, drive at 20 km/h for a short while, then again for a short time 25 km/h, then again 15 km/h, etc, so that you constantly change speed.

After 300 km, speeds can be increased, but keep 'playing' with the throttle for the next 200 km. However, after the first 500 km does not drive at full speed constantly.

In practice, only the following malfunctions that are likely to occur with the Berini M13 are:
A) carburetor (nozzle or strainer clogged)
B) Ignition (spark plug defective)

A. The carburetor
The carburetor ensures that a correct gasoline/air mixture is maintained. This mixture is created by atomizing and mixing the gasoline entering through the nozzle with air entering through the air filter. To avoid contamination of the nozzle (blown nozzle) and the mixture (carbon build up), both the gasoline and the air are cleaned by the fuel filter and air filter. Keep these clean regularly cleaned, making sure that the fuel filter always gets fitted back in the nipple properly. Pay close attention to the two fibre rings here: don't lose them!

Should the nozzle nevertheless become blocked, you can remove the nozzle holder with the internal hexagon of the spark plug wrench and then remove the dirt by blowing with your mouth or bicycle pump. Before doing this make sure the fuel cock is closed! Preferably remove the nozzle from the nozzle holder and always blast it in the opposite direction to the normal gasoline flow. Do not forget the fibre ring during re-installation.

Repeated clogging of a nozzle indicates fuel contamination. In this case, the fuel tank, tap, line, and float chamber of the carburetor should also be thoroughly cleaned.

Important: Never attempt to pierce the nozzle with a needle, pin or other sharp object. This will cause irreparable damage to the nozzle.

B The ignition
The Berini M13 combination is equipped with a Bosch ignition with a light coil (not on the Berini M13 engine sold separately). The spark that ignites the gas mixture in the combustion chamber of the engine is generated by a powerful flywheel magnet. this mechanism consists essentially of a standing base plate on which the ignition coil, capacitor, interrupter and light coil are mounted. The flywheel contains 6 built-in magnets. When these strong magnets rotate along the coils, electric current is generated in the windings of these coils. Whenever the contact points of the breaker separate, this electric current is increased in the ignition coil to a very high voltage (approx. 10000 volts). This high voltage current is fed via the spark plug cable to the spark plug, where it creates a powerful spark between the electrodes. This spark ignites the gas mixture in the cylinder.

With the Berini combination, a current is created in the light coil in the same way, but without the interrupter points, which causes the lamps to burn.

The Spark Plug
As mentioned before, the spark plug ensures that the fresh gases drawn in in the cylinder are ignited. This is done by means of an electrical loop voltage generated in the fly-blade magnet, which at the right moment causes a spark to jump between the spark plug electrode in the combustion chamber.

The electrode points must have a distance of 0.4 to 0.45mm. This distance is very important and should never increase as there is a good chance that the ignition coil will eventually become defective. Please check the electrode position at regular intervals.

If the engine should suddenly stop while driving, the spark plug must be removed with the supplied special spark plug wrench which you should always carry with you.

Check that the spark plug is clean internally: if not, fit your spare spark plug. At the next opportunity, the dirty spark plug is cleaned by disassembling it, cleaning the inside and adjusting the electrode gap. Spark plugs that cannot be dismantled are cleaned by heating them over a gas or welding flame to remove the carbon build up. Consult an official agent for this purpose.

We recommend that you always use a removable spark plug: this simplifies the cleaning procedure.

When reinstalling the spark plug, the corresponding packing ring must be present.

The spark plug should be tightened securely, but not over-tightened.

No 'pearls' should form on the spark plug electrodes (not to be confused with so-called; carbon bridges' or' lead bridges', which have other causes, including contaminated fuel, dirty air filters, etc.). If pearls form, this indicates that the engine has overheated. In this case, an official agent is consulted.

To make sure that a powerful spark is present, proceed as follows:
a) remove spark plug;
b) Reconnect spark plug wire to spark plug normally;
c) place the spark plug on top of the cylinder head;
d) Engage motor and drive bicycle one or two steps by hand.

There should be a crackling blue spark between the spark plug electrodes. If not, try another spark plug. If no spark is visible, consult a Berini agent.

Free Service
Careful monitoring of your machine is necessary, especially during the first month. In order to insure this, the official Berini agent will provide you with free service upon presentation of the warranty certificate for one month after the date of delivery.

The activities pertaining to this are exclusively those that are necessary to keep the motor and bicycle in a reliable operating condition and include, inter-alia:
1, Check and adjustment of spark plug and breaker points;
2. Checking of nuts and bolts;
3. Checking and adjustment of carburetor and air filter;
4. checking and adjustment of the clutch mechanism;
5. Checking and lubricating the coaster brake.
De-carbonizing the engine is not included.

In this context, we would like to point out the warranty conditions on the back of the warranty certificate, which state, among other things, that the bicycle must have been checked at least twice by an official agent during the first month.

Please consult the agent list that you have received together with the warranty certificate.

In addition to the free checks described above, it is of course necessary that regular attention is also paid to proper maintenance after this first month. The maintenance work, as described below, can be carried out in part by yourself, but caution should be taken against carrying out work which requires preeminently technical knowledge, which must be carried out by an official agent.

Work that one can carry out oneself
1. Regular cleaning of the bicycle and engine. If road dirt has accumulated between the cooling fins on the cylinder, it should be removed using gasoline and a brush.
2. The clutch mechanism should be cleaned regularly. The locking mechanism (sliding piece) must never be provided with oil or grease.
3. Oiling the brake pivots, cables, handles and coaster brake.
4. Regularly checking all nuts and bolts, as well as the functioning of both brakes.
5. Regular cleaning of the spark plug.
6. Cleaning the carburetor.
7. The air filter should be washed every 2000 km in clean petrol and then provided with a few drops of engine oil. Pay particular attention for cracks and other openings, which must not occur.
8. Regularly checking the tire pressure, especially the front tire.

Activities that must be carried out by an official agent:
a) After every 1500 km (approximately 75 hours driving) the muffler and exhaust port in the cylinder should be cleaned.
b) After every 2500 km the cylinder head and the piston must be de-carbonized.
c) Check the carburetor every 5000 km, paying special attention to the float needle and the float valve seat. It is possible that after this distance has been covered, both the latter and the spark plug will have to be replaced.

Other audit activities to be performed by an Agent include:
• The ignition mechanism;
• The engine suspension;
• The clutch mechanism;
• Headset, bracket, hubs, etc.

Winter storage
If you wish to put your Berini M13 'in a stable' for a long time during the winter, we advise you to take the following actions in order to avoid difficulties when putting it back into operation.
1. Always de-calcify first, so that the engine is completely clean internally.
2. Immediately before storing the bicycle, drive a minimum of 10 km to ensure that the engine is thoroughly warm when it is put away. This is necessary to evaporate all internal moisture (if the engine is not properly war, water from the combustion of gasoline may condense in the engine, which can affect the interior, among other things, ball bearings and crankshaft).
3. Thoroughly clean the entire bicycle and especially the engine of all grease and dirt.
4. Dismantle the carburetor and rinse it in clean petrol and make sure that it is completely dry internally.
5. Empty the tank (disassemble the fuel tap) and flush the tank with a mixture of 1 part petrol and 3 parts oil, so that it is completely 'lubricated' internally. This is to prevent possible rust formation. When gasoline is left standing for a long time, the phenomenon of 'gumming' occurs, creating a sticky substance that can clog all supply lines and is extremely difficult to remove.
6. Keep the entire bicycle in a dry place, otherwise damage may occur to the electrical mechanism, which can cause the coil to burn out. In addition, rust is an extremely dangerous enemy.
It is best to coat the entire bicycle in oil or grease with a brush and pay particular attention to the connections of the parts (fenders, frame, wheel nuts, etc.).
7. Dismantle the tires, apply plenty of talcum powder and pump them up. Check the voltage every 10 to 14 days.
8. Remove the spark plug and pour some oil on the piston through this hole. Turn the crankshaft a few turns so that the oil can spread over the cylinder wall.
9. Regularly turn the motor a few turns e.g., once a month.

Never let the engine run under its own power during this period; this causes damage to the interior! We are convinced that the Berini M13 will serve you faithfully for a long time if you pay the necessary attention to the above.

We would like to wish you many successful rides and a good journey.

Berini Motorcycles: