Simon,
Douglas did publish a thirty page workshop book covering the T6,S6, S5, C31, D31, E31 models. !932 models would mechanically be identical. Also there was an accompanying illustrated spares list. As the S6 variants were one of Douglas' more popular heavyweights, you can still find original copies at the autojumbles. Also reprints are available from John Withers. See his advert here-
https://www.douglasmotorcycles.net/index.php/topic,148.0.html My carb faces down... and when it drips petrol onto the hot pipe becomes quite unnerving. Is this a common problem... ?
Oh, you mean like when it bursts into flames and provides the carb pre-heat on those frosty mornings? Just kidding. I am not sure if it was an intensional part of the design to draw warm air off the exhaust pipe. Usually some sort of shroud is incorporated if that is the intension and I have not see such offered by Douglas. Certainly a few drops vaporizing on the exhaust pipe are not going to start a major conflagration, but the carb should not be dripping excessively unless you have just depressed the float tickler. For all its odd appearance, the carbs used on the S6 are just a variation of the contemporary T.5 Amal carb, made specially by Amal for the S6 models. Many of the Amal T.5 internals interchange. Except for the needle, which is shorter than the standard Amal vertical carb.
It sounds like you float level might be set a little high (either the setting or a worn float needle is not sealing) if it is excessively dripping. With a horizontal main jet, the float level is more sensitive to being 'just right' than otherwise. The afore mentioned handbook has four pages on tuning the 5/116/S carb, but no mention of the float level setting. It should be set just below the main jet. If the washer sealing the float to the base of the mixing chamber is sound, vacuum when the engine is running will cause the fuel level in the jet well to rise and so submerge and draw fuel through the jet. Others running S6 models may have suggestions on more precise measurements for the float level.
-Doug
