Author Topic: CF prefix  (Read 5453 times)

0 Members and 1 Guest are viewing this topic.

Offline Ian

  • Master Member
  • ****
  • Join Date: Jul 2004
  • Posts: 1233
  • Location: The Oaks, NSW, Australia
CF prefix
« on: 23 Feb 2010 at 05:47 »
Hi folks - I have come across a frame with number CF15** - it looks heavier than a 2.75hp one. Looking through the id charts it seems to say that it would be 25 or 26 2.75 - but then the number is only 4 digits. In the same place I found a frame with a number falling in the 25 engine number range but with no prefix. (75***)

Looking at the other charts the only possibility is where the ? is against the 23-24 S2 - engine numbers CE - does that mean frame number CF ?

Any ideas appreciated.

Offline Chris

  • Master Member
  • ****
  • Join Date: Jun 2004
  • Posts: 490
  • Location: Kent, UK.
Re: CF prefix
« Reply #1 on: 23 Feb 2010 at 08:22 »
Hi Ian
    The CF prefix signifies that the frame is for the 2.3/4hp CW model and the vast majority of these had only four digits following the prefix. I believe the numbering started at CF100 and only a few with three digits survive and then four digits continued up to CF9999. There are only a couple of machines in the register with a five figure number. The CW frame is heavier in some respects in that the rear fork especially is much wider at the front end to take the larger section mudguards. There are other minor differences between the CW and TS frames and front forks. A plain five digit number on the other frame with no prefix shows it to be the standard 2.3/4hp TS model frame. Although the frame numbers changed for the introduction of the CW model, engine numbers continued sequentially with their five digit numbers until the end of 2.3/4hp production when superseded by the EW.
Chris.  

Offline Ian

  • Master Member
  • ****
  • Join Date: Jul 2004
  • Posts: 1233
  • Location: The Oaks, NSW, Australia
Re: CF prefix
« Reply #2 on: 23 Feb 2010 at 19:10 »
Thanks Chris - that makes sense - it was the rear of the frame that looked different. The ID charts are a bit confusing for that year.

Offline Doug

  • Global Moderator
  • ****
  • Join Date: Mar 2004
  • Posts: 3199
  • Location: Pennsylvania, USA
Re: CF prefix
« Reply #3 on: 23 Feb 2010 at 23:49 »
Sounds like another amendment to be made to the identification chart. I will have to get on with pushing out the next revision.

-Doug

Offline Alan Cun

  • Master Member
  • ****
  • Join Date: Feb 2007
  • Posts: 419
  • Location: Qld Central Burnett District
Re: CF prefix
« Reply #4 on: 18 Oct 2011 at 08:57 »
Hello All,

I received an email from a member of an old machinery forum in relation to my Doug collection and the offer of some parts. Now this gent insists that the parts came from a 750 S2  1921 that he believed probably got dumped when the area was demolished around I believe 1980.

Now here is where it gets weird when I was living in Sydney in 82 I bought a S1 frame with attached sidecar from a gent that got it from the San Sousi tip. Many of the items on the frame resemble the parts shown on photos I have received from the machinery member. This is now my restored S1 elsewhere on the forum.

Now if this is the frame from the 750 is it possible the  factory used both motors in the same frame. I have used the above section of the forum because according to the Jeff Clew book CF 828 my frame number is for 3 1/2 OHV brazed frame.

I have permission to use the members info on the forum and the pics provided I dont use his identity. Look forward to any comment and will sort email and pics to post later.

regards Alan

PS I dont know but when I try to work out the letters on my two restored CW bikes they seem to have the prefix OF. Spare frames hung high in the shed were a little out of reach for a quick look but I will attempt a visual later.








« Last Edit: 20 Oct 2011 at 19:44 by Dave »

Offline Doug

  • Global Moderator
  • ****
  • Join Date: Mar 2004
  • Posts: 3199
  • Location: Pennsylvania, USA
Re: CF prefix
« Reply #5 on: 19 Oct 2011 at 01:22 »
Alan,

Nothing has come to light yet to suggest that the S1 and S2 used different frames. Since they both had the same stroke and shared a common (dimensionally) bottom end, there is no technical reason that the 733cc (6hp) S2 would require a larger or different frame. There is evidence in the 1921-23 spare lists that the 3-1/2hp Sports frame did go through more than one iteration; part number 720s being assigned specifically to 1921, and 1180s to 1922-23. I do not know the details as to what was different. While it is possible Douglas allotted it a unique prefix to denote a frame allocated to 733cc verses a 494cc, no unused prefixes are available in the range (AF through TF), but more on this anon

Things get a little more confusing regarding the CF prefix. CF seems to be assigned to the all-chain drive CW side-valve model, judging by the number of examples in existence. So the reference to a CF prefix being assigned to a "3-1/2hp OHV brazed frame" in the appendices of Jeff Clew's book is at first glance apparently an error. There are several other typos and errors in those appendices that have subsequently come to light through research that make it a possibility. However... at least four people that have OHV Sports models claim to have CF prefix frames. This seems to be too many to be a case where the information was taken down incorrectly, or a typo in the LDMCC registry. It looks like Douglas used CF on both the CW model, and the OHV Sports models.

Just to muddy the waters further, there was a BF frame prefix according to Clew, no examples known, assigned to simply a "2-3/4hp". So was this the frame prefix that should have been assigned to the CW side-valve model? Well not so fast, because in the 1921-22 OHV Sport spares list, there is mention of pistons for a 2-3/4hp OHV Sports version! I can not recall ever seeing this cataloged properly, though there is a mention - almost as an afterthought - of in in a 1921 3-1/2hp Sports model brochure. It is possible the frame prefix BF belonged to the 2-3/4hp OHV Sports model. Though as with the 6hp verses the 3-1/2hp, I do not know why a different frame would have been required (and none is given in the spares list.) I have not seen a picture of what a 2-3/4hp OHV Sports model looked like. The reason for this tangent conjecture is the engine/frame/gearbox prefix allocations at the time followed a pattern, which quickly fell apart for practicality reasons shortly after the introduction of prefix codes. So we have:

Model, engine prefix/frame prefix/gearbox prefix
3-1/2hp OHV Sports, AE/AF/AG
2-3/4hp OHV Sports, BE/??/BG 
6hp OHV Sports, CE/??/DG

A,B,C and E for engine, F for Frame, and G for gearbox, a real cypher!  :)

So we see frame BF fits nicely into the pattern for the 2-32/4hp OHV model, which chronologically would seem to be the second model offered. So by rights the 6hp should have frame prefix code CF, but we have seen this has already been used on 2-3/4hp side-valve CW models too. And the pattern is already beginning to unravel as gearbox prefix CG was already allocated for something else.

So my best guess is frame prefix AF was for the 1921 Sports model (Jeff Clew states it was for 1921 only) at which time only the 3-1/2hp was offered. Then came the 2-3/4hp with frame BF, though whether any were ever sold is a matter of speculation. Then came CF, which was needed to denote the changes between the 1921 3-1/2hp frame, and the 1922-23 version. This prefix was also allocated to the 2-3/4hp side-valve model (or vice-verse), for reasons unknown. Alternately it is possible the AF/CF denote the differences between the 3-1/2hp and the 6hp, but this then means the AF entry in Clew's book is in error too.

Further confusion is the 1921-23 spares list states lists one frame for 1921 models, and another for the 1922-23 years (as noted above.) But the 1922 spares list (issued May 1922) only mentions the earlier frame! If that were not odd enough, the earlier spares list mentions the 2-3/4hp pistons, but no cylinders or heads to go with it! The later spares list, issued Dec 1924, does the same and adds the interesting tidbit certain parts (obsoleted) were available for the 1920-21 models.

Anyway, if anyone can throw more light on the subject I am all ears.

-Doug

References:
1921 3-1/2hp OHV Sports Brochure
1922 3-1/2hp OHV Sports Handbook
1921-1922 3-1/2hp OHV Sports Spares List (illustrated)
1921-1923 3-1/2hp OHV Sports Spares List (unillustrated)
« Last Edit: 19 Oct 2011 at 01:53 by Doug »

Offline Alan Cun

  • Master Member
  • ****
  • Join Date: Feb 2007
  • Posts: 419
  • Location: Qld Central Burnett District
Re: CF prefix
« Reply #6 on: 19 Oct 2011 at 09:11 »
Thanks Doug,

The CF is very clear on the brazed on gearbox plate on the lower frame rails. Our good friend Rob from WA phoned today and said he has crank cases and the barrel bases are much bigger than the S1. The more I look at the pic supplied by Frank in particular the tin leg shields , footboards and the fact a side car was attached leads me to believe I have the same machine. The body of the sidecar was mangled beyond repair and all the tubing or what should have been tubing was solid steel.Very heavy. At a later date I did see another side car frame of the same heavy construction near Gunnedah NSW.

Alan

« Last Edit: 20 Oct 2011 at 19:48 by Dave »

Offline Dave

  • Administrator
  • ****
  • Join Date: Mar 2004
  • Posts: 3041
  • Location: New South Wales, Australia
Re: CF prefix
« Reply #7 on: 20 Oct 2011 at 19:46 »
Photos added to Alan's posts above.

Offline Alan Cun

  • Master Member
  • ****
  • Join Date: Feb 2007
  • Posts: 419
  • Location: Qld Central Burnett District
Re: CF prefix
« Reply #8 on: 28 Oct 2011 at 09:49 »
Hello All,

Was lucky enough to receive the 3 items shown in the photo and was happy to get the correct lever set for my cycle. The EIC instructions in an enclosed 15 page. First I have ever seen. Can anyone identify the plug it remains a mystery to me.

I have had considerable emails basically confirming the bike I have is non other than the 750 brought into Sydney in 1921. Frank who forwarded the parts has contacted the family member of the bike (John) who he knew in 1950s. He said that he talked to Billy Connaulty (Doug agent early 20s ?????) about 1951 and he thought only one 6hp Doug was in Sydney in or around 1921.

regards Alan