Triple or Twin Carbs

[eastendjohn]

I have recently received back my XK120 Replica Aristocat from mechanics. While I am please overall, there is still a problem with even modest acceleration being sluggish it's still troubled by a backfire! The car has triple 2" HD 8 carbs with the fabled AED choke. While the car was away I purchased a set of 2" HS 8 carbs complete with inlet manifold and a manual choke adaptation. I am not a mechanic but the swap is pretty basic I think. So do I take the plunge and go for fewer (twin) carbs option, ditching the auto choke to give me a smoother ride? I am a sedate and not a power driver so for me three carbs is an ego trip only.

[3.8etypephil]

The valve timing, clearances, ignition timing, mixtures, or a combination thereof must be incorrect if the acceleration is sluggish and accompanied by backfiring.
Look for air leaks / vacuum pipes disconnected to start with; the cheapest and easiest thing to fix.

[PaulGover]

I have recently received back my XK120 Replica Aristocat from mechanics. While I am please overall, there is still a problem with even modest acceleration being sluggish it's still troubled by a backfire!...

Probably far too late to be useful, but have you checked the damper/dashpots on top of the carbs are full of oil? I think you're supposed to use SAE 30 or some such monograde oil, but I always used engine oil as it was handy. Without it, the mixture weakens under hard acceleration, and AFAIK that causes backfires.

[eastendjohn]

Never too late Paul. Many thanks

[eastendjohn]

The valve timing, clearances, ignition timing, mixtures, or a combination thereof must be incorrect if the acceleration is sluggish and accompanied by backfiring.
Look for air leaks / vacuum pipes disconnected to start with; the cheapest and easiest thing to fix.

Very welcome input I went through each of these and paid particular attention to the timing and distributor setting. She is purring again thank you