Oil Filter -Norton  Commando, etc.
David Comeau    11 August 1989  U/D Apr 2007

    The oil filter used on the Norton has  metric threads of 16mm X 1.5mm pitch.  It is about 3” in diameter and 3  3/8” tall.. One of its original applications was a Simca car (french) 1963-1972. It was also used on Citroens 2CV, Dyane 4 & 6, Matra, and Peugeot.  More recently, this size was found on my 907 IE Ducati motorcycle. There are likely many more applications, but they are fairly easy to obtain, unless K-mart is your only source.
   Many people substitute with what they think are good replacements, yet are actually using a very close  SAE threaded filter of 5/8-16tpi.
  NAPA typically is supplied by WIX , NAPA  has them for me the next morning after I order it, about $9 or so, unless they make you pay full retail. Unfortunately WIX officially disclaims (12 August 1988)  suitability for the Norton application in writing to me, but gave me no reason why! They make a good filter and I still use it with confidence.
  The Ducati filter was $9.50 last time I got one.
  Getting a filter has never been a problem for me. I've gotten ten packs from  Norvil MC in England for about $4.35ea(2007 over $9). I got a batch of NOS Beck Arnley at a British MC flea market for $2.00 ea (I bought them all).
  The fact that many of these filter are of a higher bypass rating than the Norton filter is a slight technical difference, but of no practical concern for our Nortons since they filter the return oil.  Please advise me of any corrections or additions, as I have not verified all of them myself. If you have a used filter,  one of the untested filter listed below, contact me, and I will test it for it's bypass data.  dynodave@gis.net
I am not endorsing any particular filter, but just showing ones with the 16mm threads

Part  #         Bypass pressure    tested?

      Low bypass group 8-15psi
NVT pn 06-3371       10-14psi                     yes, I measure it
Crossland 631           probably 10-14psi
Mahle OC 5              12-16psi
Mann W713              13psi
MANN W712/11      15psi                            NN49
NAPA 1352               (Crossland 631 was once supplied) $8.99   jan 2000
WIPAC CA111         12psi                            yes
WIX 51352                                                   (OEM to napa)

NAPA  1032               8-11psi bypass
16mm x1.5mm thread-3.4” tall x 2.9” OD-gasket 2.73”OD x 2.43”ID
There is no check valve, but it shouldn't matter- $ 6.78 sell price/$13.05 full list (JAN 2000)
subs for napa 1032 -thanks Bruce
Wix....51032-who makes NAPA

      High bypass group 18-23psi
AC X-4                           18-20psi                  Haynes Manual
Beck Arnley 83-0008    18-20psi                   (GUD Z 102 supplied)
Champion H101            23psi                        donated by Don Workman
Citroen 54277744, 75491083, 75518393    by cross reference
Crossland 673               18-20psi                  INOA Tech Digest
Ducati 0905A9960         23psi                       yes
Ducati 065149960, 090549960                    by cross reference
Gilera G400066                                            by cross reference
GUD Z 102                     18-20psi                  yes, by me
MANN W712/9            21psi                         INOA Tech Digest
Purolator FC 601           18-20psi                  yes
Peugot 110979                                               by cross reference
Talbot 0012851491, 0016339700, 0061501500, 4040613395

      Bypass unknown/unverified
BAP/GEON 11-18700
Beck-Arnley 041-0241                                  has supplied knetch AW13
Fram PH2839
Fram PH2873
Fram PH2884                                                    not verified
GUD Z64                                                           not verified
Knetch AW 13
HARMON S-389                                              Jim K.
Purolator FC 103
Simca 29932M
Simca 41023
VERA 10-00397
Unico LI 774/9

this list is for filters potentialy available in north america

Oil filter housings 06-3139
more to come on the various housing that were available over the years and today...