Looking at period pics the WNG twistgrip it is quite a bit longer than the standard Amal type. I have read on another forum that they were 7" long (inc the housing) compared to 5 1/2 for the normal one you see, and the photos seem to bear this out. The extra length is present whether it has a rubber grip or the later canvas one. The 'dummy' grip on the left side is also longer than normal, about 6 inches compared to 4 1/2 normal.
Looking at the parts books the dummy grip 6430K-39 is the same part number for the WNG AND the 1939 singles meaning the singles must also have had the longer grips fitted ?.
The twistgrip assembly is 6430-40 for the WNG and 6430-39 for the singles. I am assuming the difference is because the WNG did not have a chrome plated housing but could be wrong?
The 1944 WNG parts book gives an Amal part number for the twistgrip 16/117C....the C I think is for canvas. It is still the long version as shown in the bottom image of an original 1944 WNG. There are 16/117’s listed on Ebay but they are the short ones.
I have tried Drags, they list a 6430-40 for WNG but theirs is 5 inches long, as is their 6430-39 (same parts) listed a superseded so not the original spec.
So...does anyone have any leads on where I can get a longer twistgrip? I saw a NOS with canvas grip went for £102 on Ebay earlier this year !!