General => Douglas Motorcycles - General Discussion => Topic started by: ted on 05 Nov 2004 at 11:23

Title: Twin carbs on dragonfly
Post by: ted on 05 Nov 2004 at 11:23
I have recently purchased a 1956 dragonfly at auction,this was the bike that had been on display at the National Motor Museum since 1979.
I have spent a lot of time getting it in running order.
The bike has twin carbs Amal 375's.
The original twist grip was very stiff and difficult to operate.
I have fitted a traditional type twist grip and oiled all the cables but it is still rather stiff to operate.
Has anybody any ideas on how I can make the twist grip easier to operate.
At present the single bowden cable from twist grip goes into a black plastic spliter and then to each of the carbs.
Any ideas would be apreciated.
Title: Twin carbs on dragonfly
Post by: Doug on 05 Nov 2004 at 12:54

Well you could go back to the stock Dragonfly arrangement of a single carb!   :D

I run a Mark 3, which has twin Amal 274 carbs, and yes it is the nature of the beast that it has heavy throttle action.  It is inherent as you are pulling against two throttle slide return springs.  

About all you can do are the obvious items that you likely have already thought of.  That is, switch to Teflon lined cable casing.  Also the plastic cable splitter box might be a bit flimsy and is binding under load, offsetting the natural lubricity of plastic construction.  If you think that is it, there are plated brass versions about, as used originally.  You could look for lighter springs for the throttle slides (not sure if they exist) but unless your carbs are well bedded in (that is worn out!) you will find the stock springs are required to positively shut the slides.  There is nothing more exciting than rolling off the throttle and then kicking the carbs with your toe to try to get the engine to slow down!  I re-sleeved my carbs and at first they tended to stick.  Without an air filter, they do wear in quickly.