rewdco

Very nice bike Ian! Well done!

Made them with a detachable stud Ian! Just like the originals! 😁

Glad to see that I've been able to help you reunite your bike with a correct pair of crankcases Ron! Keep up the good work!

Jan

Looks like the 1" 3/8 bolt was definitely used in 1942 (see 1942 picture below). I guess this was soon noticed and the factory may have fitted longer eye bolts for the footrests on later contracts. But the parts catalogues were never amended, up until the 1945 contracts they give the same number, being the number for the original 1" 3/8 bolt. 

If you compare the mounting position of your pillion seat with the pictures below, you will notice that the pillion seat on your W/NG is mounted further forward Ron! Think you will have to start searching for this Ariel version... 😕

It is now confirmed that only the part with the pressed in "ACUMEN" logo was leather, the rest of the cover was Rexine...

I've added some new information in the "long Acumen" post. There was a slightly different version which was only used by Ariel. See further above...

Jan

23 hours ago, rewdco said:

Would also like to add some pictures of original covers. Starting with the ACUMEN long version:

 

 

From Grace's Guide:

Acumen Co of Aston, Birmingham.

Company at the Rose Works, 133 Park road from at least 1932, and originally were described as motor accessories, pressworkers & metal spinners, but by and during WW2 described themselves as manufacturers of cycle & motorcycle accessories & leatherworkers. 

The leatherworking had been dropped by 1946, by 1965 they had added scooter accessories, and by the time of the last Kellys in 1973 were just manufacturing cycle accessories.

Leatherworkers...? I was already thinking that the scuffed edges of this cover revealed some leather instead of Rexine... I wonder if that's a leather cover on the Acumen pillion seats...?

Still better than this contraption Ron! A Lycett with front springs combined with a Lycett with rear springs makes a... Lycett with NO springs! 😂

No, serious, looks like a Lycett front springer with the springs (and the D shaped bracket at the rear) removed...

Jan

And a Lycett exception to the rule: there was only one Norton contract with Lycett pillion seats and canvas covers, every other pillion seat should have a Rexine cover... 

Lycett with front springs:

Lycett with rear springs:

Mansfield with padding at front:

Mansfield without padding at front (long and short versions):

Acumen short version:

Would also like to add some pictures of original covers. Starting with the ACUMEN long version:

Have added additional information on the Acumen and Mansfield pillion seats. Original text has been edited...

Jan

The rear spring LYCETT pillion seat :

Used by  Matchless and Norton. The seat is based on a flimsier 1 mm mudguard section, which looks "cheaper" compared with the previous 1,6 mm version. War economy version...??? But why the springs were moved to the rear is anybody's guess. A complex hinge system at the front is the result...

Hope this explains a bit Ron... 😊

The front spring LYCETT pillion seat :

Used by Ariel, Triumph, Enfield, Matchless, Norton. The seat is based on a sturdy 1.6mm mudguard section, and although they were made by Lycett, they all had coil tension springs instead of rubber springs at the top (no doubt again because of the rubber shortage). And because they had two coil springs at the front, there was no "padded cushion" at the front of the seat. Easy to recognise in period photographs: this is the only model with front springs...

The MANSFIELD pillion seats:

Quite a complex variety of models, which I will try to explain. MANSFIELD pillion seats were used by Triumph, Matchless, Royal Enfield, Ariel. The MANSFIELD doesn't use a mudguard section as a basis, but two rails (the "legs"). I have seen at least three varieties: with "X legs" and with "O legs", and also with two sheet steel strips. Not sure which motorcycle model used which legs or strips though... The triangulated front frame structure is easy to recognise in period pictures, but appears to have been used with the O-legs and sheet steel strips only. There was a version which was padded at the front, and there was an unpadded version. The unpadded version appears to have been made in two lengths.

The long unpadded MANSFIELD pillion seat with "O-legs":

Unlike the long ACUMEN, the MANSFIELD was not always cushioned at the front to avoid painful contact with the tail bone...  I guess the early versions were not padded at the front. 

The short unpadded MANSFIELD pillion seat with "O-legs":

Presumably to avoid painful contact with the tailbone, MANSFIELD also made an unpadded short version of this pillion seat. The length of the legs is identical, but the legs are peaking out further at the front of the short version (see comparison pictures below).

The long padded MANSFIELD pillion seat with "O-legs":

A further development was the long version with padding at the front. Made with two kinds of "legs": thick flat strip or thin sheet steel strip.

The long unpadded MANSFIELD pillion seat with "X-legs":

Used by Matchless (and may be others?). Looks very similar to the versions above, with the exception that the bottom rails have an X shape, and there is no triangular reinforcement at the front. Also the back end of the seat frame has a different construction. This version had no padding at the front.

The short ACUMEN pillion seat:

The very last M20 contracts (1945) used a shorter version of the ACUMEN pillion seat. Apparently because although the long version was cushioned at the front, some despatch riders had complained about painful hits with the coccyx... For as far as I could find out, only used on BSA M20, and basically the same design (same mudguard section, two coil springs at the back, but a shorter frame).

You were calling me Ron...? 😄 Here I am, with some information on the pillion seats:

It was only from about 1942 onwards that motorcycles were fitted with pannier frames and pillion seats. Before that they only had a small carrier at the back. The earlier bikes were often retrofitted with pannier frames & pillion seat during a major rebuild. Conversion sets were available...

In 1942 the first pillion seats were of the "bum pad" variety, being a metal base with rubber foam and rexine cover. But due to the sudden rubber shortage manufacturers had to look for an alternative. Enter the steel frame pillion seats... These were made by three different companies, each having his own design. These three basic designs were slightly modified during the war, so we can say that there were six variants. 

The long ACUMEN pillion seat:

This is the only make of pillion seat that was used on the BSA M20. It was also used on some Matchless G3/L and on some Royal Enfield WD/CO models. It is based on a 1 mm thick mudguard section, with two coil springs at the back. Quite a distinctive shape. On the BSA it was attached to the mudguard at the front, and to the rear carrier at the back, so not making contact with the length of the mudguard.

I have also found several examples of a slightly different version of this long ACUMEN pillion seat. There were always two holes for the spring brackets in the top frame. The "normal" version (as described above) uses the rear holes, whereas this slightly different version uses the front holes. The two rectangular cut-outs in the mudguard section are also 3/4" deeper, and the two reinforcing struts are a bit shorter. All these modifications make that the springs are mounted 3/4" further forward. 

After some research I have discovered that this alternative version of the long Acumen pillion seat was only used by Ariel. Apparently in order to move the pillion seat enough backwards to avoid contact with the tail bone, the springs came in contact with the Ariel carrier. Solution: put the springs a bit further forward... 

The position of the rear springs is the most obvious difference between the BSA and the Ariel version, but there is more:

The two banana-shaped front legs (with the hinge points at the top) are 1” longer than with BSA! Because these legs are slanted, this creates a height difference of 3/4”. The rear springs that are 1” more forward partially compensate for this height difference at the rear. In addition, the two L-plates under which the rear springs are mounted are 1/4 higher (also to compensate for the height difference) and 1/4 wider. And because the L-plates are also 1/4 wider, the length of the cross strip under the rear springs is also 1/2 shorter than with BSA! And obviously the cut-out in the mudguard section is deeper. The seat frame itself is identical to BSA.

Beati pauperes spiritu

Brave man! Will follow this thread with great interest!

Which cable length are you looking for Mark? Have got a perfect new old stock 23” cable here that I’m willing to sell...

OK, promised Ron to add some pictures of the process… Here we go:

Started by making a detailed drawing of the unfolded part: 

Transferred all the dimensions to a sheet: 

The smallest radius was only ½”, so made these with a puller: 

Added the contours, cut them roughly with an angle grinder: 

Followed by a shear: 

Pressed the handgrip with my hydraulic press: 

Closed the handgrip in the vice: 

Stretched the inside corners over a stake: 

Shrunk the outside corners over a stake, bent all the sides and made the two small flanges over a stake: 

Added the corners: 

Made the legs with a purpose made press tool, after cutting the blanks (rectangles) with a shear: 

Assembled everything on a jig and welded the legs to the carrier: 

After some cleaning: