Beautiful Australian Mk1 Ariel Square Four

It’s always nice to hear from previous customers especially when accompanied by photos and stories of their restored bikes. Roger in Australia purchased an Alternator from us a couple of years ago for his 1950 Mk1 Ariel Square Four. At the time he told me he had purchased the bike as a barn find from Canada based on emailed photographs only.

A mere two years later the photo below shows the machine restored to superb condition. This model year of the Mk1 fitted with a chrome panel tank is one of the prettiest machines. It doesn’t have quite the butch appeal of the Mk2 four piper but the deep valance on the front mudguard and single saddle give a classic line that still has elements of styling from the previous decades.

Ariel Mk1 Square 4 - Timing Side

Ariel Square Four: Growing popularity and increasing values

The Square Four has always been a mystical machine. Blessed with four cylinders from an era when singles and twins were the norm the powerful and torque laden power unit that creates so much of the attraction has also been a source of much trouble for owners. Some of that reputation is ill deserved such as the legendary “overheating on the rear cylinders” problem. Simply not true but so often repeated that you only need to stand next to a Square for about 5 minutes before some wise sage approaches you to relate this little nugget of information.

Slowly over the years the value of bikes has crept up. Although some might argue this will eventually place them out of reach it has had the advantage of driving a healthy market in components for restoration and improvement.

Ariel Mk1 Square 4 - Drive Side

Modern materials and components improve reliability

Shortcomings in the original design of the engine do exist but thanks to modern materials and manufacturing processes these have slowly been solved. Composite head gaskets, improved oil pumps from Morgo and in the last couple of years newly manufactured con-rods. Once properly rebuilt this four cylinder engine can offer good levels of reliability. Proper maintenance and regular oil changes are a must but any owner of +60 years old vehicle will do that as a matter of course.

With coil ignition the Mk1 and Mk2 Squares have always been reliant on a fully charged battery to keep going. Unfortunately with the original 70 Watt dynamo things were at best marginal. Our 300 Watt conversion based on modern 3 phase internals from Nippon Denso solves this problem entirely. Not only that it fits without modification and as you will see below is only discernible from the original on close inspection.

300Watt Alternator on Mk1 Sq4 - Timing Side

Alternator conversion makes the SQ4 an everyday machine

In a subtle way this unit transforms the riding experience. It doesn’t make the bike go faster or handle any better but it does dissolve all electrical worries. This means that you concentrate on enjoying the bike for everything it offers: Relaxed cruising, comfortable handling and  the ability to keep up with modern traffic.

Since we first introduced the Ariel Square Alternator conversion in 2010 sales have been steady. The hand built units are made to order  and the numbers sold are not significant in the scheme of things. However one has to consider that the market is limited by the number of surviving Ariel Square Fours. There are estimated to be only a few thousand of the 15,000 originally manufactured still in existence. Amazingly bikes such as this continue to surface after decades of hibernation and we are pleased to be one of the companies helping classic bike owners restore and improve these machines.

Supplied with full instructions and a fitting kit the alternator can be installed on your bike in a few hours. Reliability has been perfect and the built in sold state regulator works with both lead acid and modern gel type batteries.

300Watt Alternator on Mk1 Sq4 - Drive Side