Strange bike

[grantus]

Can anyone identify this bike? I am told The photo was taken of a friend's father in England pre WW2.
 The odd features are the radial head fins and vertical barrel fins, and also the strange shape on the side of the tank.

The muffler in front of the frame looks home made, but it also has a fishtail type that may help.

[Martin_UK]

Looks like a V Twin engine installed in a pre-war Ariel Square Four frame, cycle parts and fishtail exhaust.

Could be a home-made special ?

Martin

[cardan]

Yes it's the sidevalve version of the Ariel Sloper, which shared a frame with the square four. There are some photos of a restored one here:
http://www.vintagebike.co.uk/Bike%20Directories/Ariel%20Bikes/pages/Ariel-SB31.htm
Hard to belive, but the exhaust sytem is not only original, but was repeated on the other side of the bike!

Leon

[33d6]

It's a 557cc sidevalvesloper Ariel. Ariel produced a sloper range for 1931 & 32  and this is one of them.
The transverse muffler & exhaust system is correct.
The strange shape on the side of the tank is a rubber kneegrip and is in the style of the time.
Cheers.

[grantus]

Thankyou very much, you guys are great!

[arielguy]

It is a 1931. The instrumentpanel on the tank reveals that.