1952 Ariel 500cc single racing bike

[DerekKitson]

I recently purchased a 500cc single cylinder Ariel racer. I was told it was 1952.

It appears to have been specifically built for racing with a much modified frame and equipment.

The engine appears to have good compression and looking through the spark plug hole the piston appears to be a hemi-spherical crown.

The problem is that there is a poor and very intermittent spark from the Lucas racing magneto.

I am advised that this may need re-magnetising and I have been recommended a firm on the outskirts of Chesterfield. However, before dismantling further I would like to know which model engine this is together with details of ignition timing etc therefore if anyone recognises the engine and has a manual for it, please message me.

The first priority is to get the engine up and running and to restore it to a level as a racing bike rather than pristine show.

Any help would be greatly appreciated.

Cheers

Derek

[simon.holyfield]

Tasty looking bike. TCA is the number for a 1952 VHA engine - 500cc single with alloy barrel.

Which Chesterfield firm are you talking about? I always use Tony Cooper Motorcycles in Halesowen. I'd be surprised if you don't get a few folk on here recommending him besides me!

[Simon.Gardiner]

Hi Derek - welcome to the forum.
As Simon H. says, tasty looking bike.
Ariel 500 single engine - looks to have a standard (1954-on) cast iron barrel, do I see aluminium paint? This basic engine goes back to the 1930's (or even further), the details changed but most parts are interchangeable so ignition timing will depend on what's inside and what it runs on. The factory advice was always 5/8" BTDC for high compression engines (1/2" for low compression engines - I have got those figures the right way round, the advice goes against what you'd normally expect but that's what it is! ) but as that's a manual advance magneto you'll be able to tweak it on the lever.
It's difficult to tell from your photos but that frame looks a bit like one of the contemporary (ie early '50s) swing-arm conversions (to rigid/plunger frames) that were available before the factory swing-arm came out.
Regarding the magneto, as mentioned, many people round here will recommend Tony Cooper, I can think of at least two others that I use ('cos they're nearer to me), offhand I can't think of anyone in Chesterfield though.

SG

[john.whiting]

The compy mag is likely from a Matchless......its a "wader" ,supposedly waterproof for a trials bike.The bike is pretty typical of the poor mans club race bike of the late sixties......the supply of cheap Gold Stars and Inters had dried up,and Ariels with their steel flywheels fell under the hands of the "blow an engine every weekend" crowd.......Unfortunately they couldnt get within a mile of the Jap two strokes,or even a Tiger 100,which is what I had in a wideline featherbed.

[nevhunter]

When you get the compression ratio up on a deep head the compression space resembles half an orange skin and the flame travel is not as quick so you need the extra advance on the ignition. Some of the alcohol JAP twins were using more than 40 degrees of advance. The steel flywheels were not used on the later 500 OHV's Mid 50 's on (Good Ole BSA ) and earlier ones were usually fitted for race work as the others disintegrated at revs.. Nev

[adrie.degraaff]

What can i add to it that's helpfull?

It could be a 1952 VHA-VCH head if the sparkplug is pointing forward.
It could be a McCandless conversion rear springing.
The crankcase is 1951-1953 but doubt the number as is first polised and than stamped.

There isn't much you could use on the road so racing is the thing but that's a money pitt.

[adrie.degraaff]

There is a small chance that it's an ex factory or Eric Cheney scrambles machine, there for you need to give the frame number wich is behind the carburettor top.

[jj.palmer]

The company that you may be refering to could be "Armoto Ltd", Chesterfield, post code S44 5HS, tele 01246 826667.

John P.

[david.anderson]

As Adrie has said it is an alloy head and probably VCH VHA. With a VHA engine number it is most likely that the original alloy cylinder base flange cracked with high compression and has been replaced with the iron cylinder. Lucas Wader magnetos were also fitted to competition Ariels.The rear wheel is post 1956 Ariel. Appears to be a nice build.
David

[DerekKitson]

Thankyou all for your quick and helpful replies yes the company recommended to me is indeed Armoto Ltd they are quite close to me as I am located in north Notts.Am still looking for a workshop manual for engine and gearbox which is a Burman unit with kickstart removed to accommodate the rearset gear change .Once again thanks

Derek