I've just discovered the secrets of the "Siren" through your various posts.
Mine has a frame number XG 23610, which, according to initial research, dates from February 1942.
Its engine is an RAF RBH 25..., which may not be its original one.
In the purchase agreement, there's another engine, a BH 15..., which might be its original one. Further research will be needed.
Prestone
Last edited by Prestone.M on Wed Feb 18, 2026 2:47 am, edited 1 time in total.
Welcome to the fascinating world of Ariels and W/NG in particular.
XG 23610 comes from a batch of number that are not listed in the despatch book. It is assumed that these numbers, there are many, belong to frames supplied as spares with each contract. This batch of unlisted numbers is from 23,512 to 23,750 and is between contact C 10,477 that was completed in March 1942 and contract C11,103 begun February 1942. The engine numbers may help to work out which contact this bike came from as most W/NG do not have the original engine but most have one from the same contract. Any other numbers would be good as well such as the gearbox.
Roger Gwynn, caretaker of the club's works drawings and machine register, membership secretary 2015-26. Director of AOMCC, Draganfly Motorcycles, Craven Equipment and Supreme Motorcycles mostly retired.
That does the job. Engine is from contract C/S 14218 which was for the RAF in 1943, The frame I read as XG 23810 rather than 23610, which does exist as a 1942 Army W/NG from contract C 11103. The gearbox is the correct type and is probably from 1942 though they are difficult to date. So the siren has been shaken, whatever that means, possibly lost a little in the translation!
Roger Gwynn, caretaker of the club's works drawings and machine register, membership secretary 2015-26. Director of AOMCC, Draganfly Motorcycles, Craven Equipment and Supreme Motorcycles mostly retired.
I need to ask you to post images directly and not as links to pictures hosted on other sites. These other places have a habit of changing over time, we've already lost a lot of earlier images that were hosted on photobucket and similar.
Milkshake I understand now.
This motorcycle was supplied as part of a contract for 3,500 W/NG dated 27th February 1942; delivery to Chilwell Ordnance Depot commenced on 10th February 1942 and was completed on 11th August 1942. The specification was as contract C 10,477 and they were to include pillion seat, footrests, and pannier bags. Also supplied were 210 engines, 158 frames and 140 gearboxes. They were to be delivered at 650 per calendar month after contract C 10,477 was completed. They were allocated census (tank) numbers between C 4,692,899 and C 4,696,398. The engine numbers were BH 15,001 to 18,500, the frame numbers were XG 23,751 to 27,250 and they cost was £62/-/- each. Census (tank) numbers were usually applied at the factory prior to despatch in approximately date order, however the motor cycles were not built in numerical order
Roger Gwynn, caretaker of the club's works drawings and machine register, membership secretary 2015-26. Director of AOMCC, Draganfly Motorcycles, Craven Equipment and Supreme Motorcycles mostly retired.
Nearly! The original engine for XG 23610 is BH 15073. Very few W/NG have their original engines because if there was a problem with the engine, instead of repairing the engine a spare one would be fitted and most of them had a hard life. If you have an engine from the same contract this is very good. I assume that your frame number is 23610 not 23810?
We now know that 'milkshake' is Belgian for 'bitsa' (as in bits and pieces from all sorts of bikes), does SIREN mean the official vehicle number that the police use to send you nice letters about riding too fast?
Roger Gwynn, caretaker of the club's works drawings and machine register, membership secretary 2015-26. Director of AOMCC, Draganfly Motorcycles, Craven Equipment and Supreme Motorcycles mostly retired.
