Hi, and thanks for the info re: BMW engines. Yes, the BMW's are on the heavy side, but not nastily so. The new R1200 produces 122hp, and standing on the runway weighs in at 172lbs, I'm told. That's not a disaster. But if I can get the same power from something lighter, and especially if it is an inline 4 which will tuck neatly under my cowl, then why not?
I've come across a great Australian web site which gives writeups and specs for a wide range of Jap motors here. Of special interest for me is the Daihatsu 1.3 litre K3-VET engine, as found on some Sirions and on the Terios.
As they say:
The 1.3 DOHC, 16-valve intercooled turbo K3-VET engine uses a 8.5:1 static compression ratio and achieves up to 103kW at 6400 rpm and 177Nm at a surprisingly low 3200 rpm
103Kw = 138hp. And all that torque at only 3200 RPM. Could even fit a great big prop and no redrive???
And it makes max HP at only 6400 rpm. Bolt on a 1:2.3 gearbox, and you're cooking with gas! The non-turbo version puts out 83Kw (108hp)
A high-performance atmo version of the K3 1.3-litre – K3-VE2 – is also available with variable cam timing. In the top-line Japanese Storia, this engine spits out an impressive 81kW at 7000 rpm with 126Nm of torque. The same engine is used in the locally delivered Sirion GTvi, though it’s rated at a more modest 75kW.
75Kw = 100hp) And it is an in-line four.
My only issue with these engines is that I don't know what they LOOK like. I bought a Suzuki K10A motor some time back (I still have it in the workshop) which is a 100hp turbo EFI job. But the fuel injection system sits so high that it is impossible to get the engine under a cowling.