1950 Ariel Square Four Mk1 *Sold £11,000*

MODELSquare Four Mk1
LOCATIONDunstable, Beds LU5

1950 Ariel Square Four Mk1 *Sold £11,000*

1 in stock

  • 1,000cc engine
  • Owned by one family from new
  • First time to market
  • Original paperwork
  • Impressive history file
  • This 1950 Ariel Square Four Mk1 sold for £11,000
  • Please scroll down the page past the video to read a full description for this 1950 Ariel Square Four

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  • 1,000cc engine
  • Owned by one family from new
  • First time to market
  • Original paperwork
  • Impressive history file

“It’s all so effortless. I can barely believe the bike I’m riding is half a century old. On the open road, the Ariel Square Four is at home in modern traffic in a way that most classic British motorcycles cannot approach. It purrs along smoothly at 60mph, accelerates briskly out of roundabouts with barely a need to use its slick gearbox, and feels more up-to-date and sophisticated than many bikes half its age”.

That was the review of Roland Brown, journalist for ‘Motorcycle Classics’ Magazine, when he rode an Ariel Square Four. Innovative, glamorous and historically very significant. These are legendary motorcycles.


The Square Four was Ariel’s most famous bike.

The exceptional 997cc engine, designed by the genius Edward Turner, had its four-cylinders arranged in an unconventional square layout.

The powerful, torquey engine made it popular for a whole host of reasons, not least its unheard of top speed of 100mph. It was without doubt one of the best bikes of the entire British motorcycle industry.


  • Registered new in Bedfordshire
  • Date of first registration 8 November 1950
  • Restored around 2008
  • Large history file
  • A video showing the original paperwork is also available here: Paperwork video

Our vendor, Colin, picks up the story for us.

When I met my girlfriend, later to become my wife, I was riding motorbikes. The bike I had back then broke down one day. My girlfriend’s dad came to rescue me. He was riding this Ariel. He had three or four back then. I’ve known it ever since. When my father-in-law passed away, I become the new ‘custodian/owner’. That has been my approach ever since I was entrusted to look after this wonderful machine. I hope the new owner not only gets as much pleasure as I have had, but takes the same custodian view of this Ariel”.


This Ariel Square Four was comprehensively restored in the mid-2000s. When we chatted in detail to Colin about the bike, he was quick to say to us, “It’s not concours”.

To be honest, we’ve never really fully understood the meaning or value of that term. At that time we hadn’t seen the images. Now we have, our view is – it is bloomin’ wonderful! Have look, we think you’ll struggle to disagree. Whether its concours or not, it is definitely a Show Winner and has in fact won awards!

The innovative design of the Ariel Square Four meant it was slim and more manageable than other in-line fours. There’s a battery on the left powering the 6v electrics and from a fairly low seat height you look down on the ammeter in the headlight, a superbly styled black-faced Smith’s speedometer, along with a small oil pressure gauge in the tank.

The Square Four’s reputation for sophistication hits you straight away. Turn the ignition on with the key below the seat at the right, and apply full choke to the Solex carburettor. The four-cylinder Ariel fires with a pleasant and distinctive sound coming from the twin pipes.

Pull away and you know you’re riding something different. Something special. That is helped in no small part to the attention this Ariel has had heaped on it and of course the great overall condition.

The unique swooping chrome teardrop design on the black-over-gold tank just tops the whole package off.


We’re told the restoration of the Ariel Square Four included

  • Engine
  • Gearbox
  • Wheels
  • All that is supported with paperwork
  • Factory warranty work documents on file

The 1,000cc Square Four Mk1 featured an new aluminium engine. This was considerably lighter than the old iron unit, bringing the Mk1’s weight down considerably.

Other notable upgrades included a redesigned cylinder head, rocker boxes and exhaust manifold. The compression ratio was increased from 5.8:1 to 6:1 giving the Square Four much better driving characteristics. The much sought after early ‘two piper’ Square Fours featured two exhaust downpipes. The Ariel emphasised its four-cylinder status with the words “Square Four” on its timing cover instead of the previous “1000.”

Because of the one family ownership from new, we understand this Ariel went back to the factory very soon after it was delivered to have ‘warranty work’ carried out which included upgrades and mods to prevent the engine running hot.

As you can see from the images, the mechanicals are all in superb order


We are delighted our vendor, Colin, has trusted us to bring this to market for the very first time since being sold from new.

Very rarely does a classic remain in one family from new. That is even more extraordinary for a classic motorcycle. We cannot recall the last time we marketed a bike like this.

The wide-ranging restoration is there for you to see. As is the retention of so many original features that made Ariel so sought after. In our opinion the balance is spot-on.

Good luck! Please remember, our site uses anti-sniping software which ensures fairness to all bidders. So, if a bid for a lot is received in the last minute, the auction will go into a 2-minute overtime period for each subsequent bid.

Bike Location: Dunstable, Beds LU5 – it’s the responsibility of the buyer to make collection / transportation arrangements directly with the vendor.

Have a question about this Ariel Square Four? Please contact the Evoke team at auction@evoke-classics.com and we will speak to the vendor on your behalf.

Guide Prices?

We’re different. But you know that. And we’re always honest. In a sector where no two classics are same, how does anyone put a ‘guide’.

Well, everyone knows the broad value of classic, let’s all be honest. So we don’t need to tell you what you already know, do we.

The ‘market’ decides and the old cliché that ‘it’s worth what someone wants to pay’ is no less true. So why kid everyone!

But, because we are different, if it really does matter to you, that’s fine, we want you to be happy. Just drop us a line at auction@evoke-classics.com and one of us will be delighted to ring you back and discuss, it’s what we do.

Tedious but it’s vital you read this, please.

We will always strive to offer the most descriptive and transparent auction listings available. However, we can’t claim to be perfect. Your own analysis is very important and we are here to help and also answer any and all queries you may have prior to purchase.

We offer and positively encourage buyers to view, or arrange inspections for each vehicle thoroughly prior to bidding.

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As with all vehicles of a certain age, localised paint repairs are common. This specifically applies with classics.

So, please, unless we state explicitly to the contrary, please assume that classic vehicles on our platform could have had remedial bodywork of any kind at some point in its life.

Two final comments on images and photos.

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If you are at all unsure, just ask us. It is what we are here for.

Finally, finally, finally. Please note that vehicles are sold as seen and a returns policy is not applicable. This is the norm for used items acquired at auction.

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Bidder Bid amount Bid time
c*********l £11,000.00 2023-02-06 22:47:58
n*************h £10,500.00 2023-02-06 22:12:49
c*********l £10,250.00 2023-02-06 21:49:57
n*************h £10,000.00 2023-02-06 18:33:20
n*************h £9,000.00 2023-02-06 10:11:21
n*************h £8,750.00 2023-01-31 18:40:49
e*********************k £8,500.00 2023-02-06 09:37:58
g********1 £8,000.00 2023-01-31 17:15:57
n*************h £7,750.00 2023-01-28 18:11:37
n*************h £7,500.00 2023-01-22 09:36:01
w*********n £6,750.00 2023-01-28 16:44:11
s*****9 £6,000.00 2023-01-20 13:19:01
n*************h £6,000.00 2023-01-22 09:18:08
n*************h £5,500.00 2023-01-22 08:54:38
f********i £5,000.00 2023-01-18 17:17:44
s*****9 £5,000.00 2023-01-20 13:12:04
s*****************8 £3,000.00 2023-01-18 22:58:14
Start auction £2,000.00 18/01/2023 12:00 AM

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