classic motorcycle forum

Hello all, I guess I'm an imposter because my "bike" is in fact a Cyclecar - a 1914 Humberette, 998cc, 84x90, 50 Degree, V-twin.  In an attempt to get more sting out of it, I'm appealing to the experts - YOU, for advice. i believe original timing was Inlet opens TDC, closes 50 past BDC and Exhaust opens 50 before BDC, closes TDC.  It's very like an early J.A.P. motor and from what I've read on your forum, the J.A.P. Inlet opens 16 before TDC, closes 65 after BDC and the Exhaust opens 65 before BDC, closes 25 after TDC - which is a hell of a difference.  Then I look at other British bikes of that era and get more confusing stats.  My dilemma is do I leave it alone or go for the J.A.P. or similar setting - so I'm asking any old blokes on the Forum, what do you think. (I've never found an original SMITHS carburettor and have previously run brass Zeniths.  I'm now about to fit an Amal model 289, my limited brain-power reasoning that if it feeds a BSA 500cc. it should feed my 998cc twin.). ANY SOUND ADVICE WELCOME.