1911 Douglas Carby

[Ian]

I am planning on recommissioning my new 1911 Douglas in the next few week. I was having a look at the carby and got a bit confused. It’s a two barrel carby. As far as I can tell it’s possibly slack cable for full throttle. Anyone have any experience with these. I believe the 13 and 14 may have used them as well.

[EW-Ron]

Do either of these look familiar ?

https://encyclopedia.pub/media/common/202210/mceclip3-635a4dff5c470.png
https://upload.wikimedia.org/wikipedia/commons/0/02/Douglas_Model_G_1912_2%C2%BE_hp_347_cc_side_valve_flat_twin_engine.jpg

As a mere duggie novice, the variety and breadth of examples is amazing !

[Ian]

It’s very similar although maybe slightly smaller. Certainly the inlet pipe is the same. I will get a photo tomorrow.

[eddie]

Hi Ian,
           The LDMCC's 1912 machine has the same type of carb fitted - and, as you suggest, it works backwards (Slack cable = full throttle)!
     Something else you should consider when reassembling the carb - the throttle slide is the plain one, the choke slide is relieved. If you swap them over, enough air gets past the relief to cause a fast tickover (and also an over-sensitive choke control due to lack of air passing through the choke passage). When setting up the cables, make sure the slides can drop fully (to obtain full opening). If the cables are very short, it is possible to get a reverse action on both the throttle and choke slides - but only to about half opening! This possibility of getting some 'normal' operation causes confusion when riders are not fully aware of the correct set up. (A couple of times I had to reset the carb on the Club's bike after borrowers had tampered with the settings).

  Hope this helps,
                          Regards,
                                       Eddie.

[Ian]

Hi thanks Eddie. I am glad I have this sorted in my brain before the first start. Sudden runaway throttle would wake me up !

I think it’s all set up properly as it’s one that was ridden a bit before I bought it.

[graeme]

Yes, slack wire. Make sure to solder on the nipple well, as when they fall off you get instant full revs  I know!