Neil Evans wrote:It's given me ideas... though I do wonder, how is it for torque compared to the A series conversion?
Complete BMW engine looks impressive: 130 hp (97 kW) @ 8,750 rpm and 117 Nm (86 lbf.ft) @ 6,750 rpm from just 1171cc.
But you've hit the nail on the head Neil. Torque output (unlike power) is dominated by engine displacement. With naturally aspirated 1200cc (or even 1300cc), max torque of any engine will never be amazing.
Even so, torque of standard BMW 1200 engine exceeds best production A-series 1300 - Cooper S 1.3i had 110 Nm. Suspect even an A-series with properly flowed head would still not match standard BMW, despite being over 100cc bigger.
Can be improved by increasing displacement or inlet charging.
The BMW engine is a
revver but still within sensible bounds, unlike many bike engines. If capacity was constrained for some reason (eg class rules), K1200RS would be high on my potential engine list...