Ariel V twin Crank

[GuyH]

The other week I stripped what I have of my 1920 Ariel V twin engine - basically the bottom end - and eventually managed to extract the crank, the remaining rod and a variety of lumps of metal twisted into interesting shapes.

As the crank fell apart I noticed the flywheels were two different sizes. I can't see from the parts book if this is how they are supposed to be or whether someone has tried to build one up from different cranks in the past. The engine had been run as a single at some point as the cam followers and other valve gear had been removed from one side and the tappet holes bunged up with pieces of wood so it is quite possible that someone has tried to fit a home made crank assembly.

I've uploaded a picture of the flywheels. Any advice on their originality - and of course offer of parts - gratefully received.........

[leon.mitchell]

Hi Guy,
I assume the engine is the Abingdon King Dick twin motor used by Ariel - I didn't know it was used it as late as 1920. I would have guessed MAG for a V-twin this late.
Anyway, I have some knowledge of the insides of AKD twins. The direct-belt-drive AKD twin (used by AKD in their own bikes) had equal width flywheels and a single bearing on the drive side. However when the motor was used with chain-cum-belt transmission - as in the case of Ariel - the drive-side crankcase was different to accommodate side-by-side ball races, and the flywheels were "odd" as in your photo. Looks weird, doesn't it?
You may not have it all, but I'm pretty sure you have the correct bottom end.
[Edit: Sorry I no longer have the AKD stuff so can't help with parts.]
Cheers
Leon

[GuyH]

Thanks Leon for the help and advice - it's much appreciated. Mine's a late AKD engine and I reckon the bike must have been one of the last to be made before changing to the taller frame and MAG engine. There's a cog in the gearbox stamped 03/20 and the frame number sits around 1920 in Roger Gwynn's V twin records. Interestingly the Ariel V twin which has just appeared in Bonham's Stafford catalogue (https://www.bonhams.com/auctions/21897/lot/197/) is dated at 1915 but the engine and frame numbers put it at a couple of hundred later than mine.

The crank set up is most definitely weird. Judging by the infernal bodges perpetrated on the engine and bike it would not have surprised me if the owner hadn't tried to cobble together a home made crank from various sources. You can see the shape of the remaining rod - all that's left of the other one is half a race which is when I guess it was converted from a twin to a single! I'm glad to hear I have the right crank so I have something to work with if I can't find a decent one.......

[leon.mitchell]

The Bonham's bike looks nice; pity it's not veteran. A9841 is the highest Abingdon engine number that I've spotted. I recall A5xxx was 1914-ish. There are a couple of other pointers to a post-war date. The AMAC carburettor with the cylindrical shield is postwar (1919-1920 introduction), and the flat oil hole covers (rather than flip-top oil cups) point to later date Druid fork.
Still, a lovely machine.
I'll keep an eye out for AKD V-twin stuff, but there's not too much of it around. JAP twin stuff is easy to find: you might be able to adapt a set of JAP rods to suit your motor. Are the cylinders in line (suggesting kinife-and-fork rods) or slightly offest (side-by-side rods). JAP rods are knife and fork.
Leon

[GuyH]

I seem to recall the bike at Bonhams was on the forum some months back when the owners sent in pictures asking for the year and value. Unfortunately I'm abroad at the moment as my work takes me away a lot of the time so I can't check the engine. Although I have photo's of the engine strip on my computer I don't have any showing the crankcase mouths. I've posted a picture of what remains of the second rod and it looks as if it could side by side. the parts book drawing appears to show knife and fork though. I'll be home in about three weeks so will check the cases then. The remaining rod is surprisingly thin and narrow unlike some V twin rods I've seen. Thanks for keeping an eye out for AKD stuff, I've found virtually nothing. Ironically, just as I have unidentified engines and bits in the back of the shed I'm sure there will be someone out there with AKD parts wondering what they're for.........

[adrie.degraaff]

There are a few Ariel V twins in Holland the 5xxx engine being 1915 and the 9xxx engine being 1919, there are ofcourse differend opinions about this.
It being pre August 1920 you can do the Horspowerrun and others.

[andyhughesflattankarielpre25]

Greetings all,here is a bit of info for Leon on AKD .I have an Ariel v twin it was found by a friend I new back in the late seventies, on its side in a field were it had been pushed to in the late forties and left,I finally got it in 1990 when he died,and left it to me,the engine no on it was A9886,this was in a very sad state just like the rest of the bike,I managed to get another engine with number A10384.Ariel used AKD in 1921 on the early chain drive models in the big heavy frames,this was not a good mix that is why they went on to MAG with the extra power.

[andyhughesflattankarielpre25]

Hi Guy the rods are fork type and the flywheels are correct ,like Leon said,very odd but hey these are ni on prehistoric,they had some wierd ideas in them days. If you need pics of any part or numbers let me know.good luck

[tony.barnett]

There are a few Ariel V twins in Holland the 5xxx engine being 1915 and the 9xxx engine being 1919, there are ofcourse differend opinions about this.
It being pre August 1920 you can do the Horspowerrun and others.

Seems about right from the numbers I have. There doesn't appear to be any 6###, 7### or 8### numbers. I have a couple of 10### serial numbers in 1920/21.

[adrie.degraaff]

Inside the gearbox casing is also a number stamped.
I think that the Ariel engine nr. is stamped at the engine factory so the engine is end 1919 the gearbox march 1920 and becoming a motorcycle in May 1920, all depending on the demand of the items.