Cool guys! Glad to know there is still interest in this post - I thought it was killer. Just want to throw out there that the "A" I have right now does a solid 32-33 and a 27 pull up hills - I'm sold on Sachs. So, I'm not raggin' on A/B/C engines.
I do believe you're right William - I do think it's a C. It's just rather confusing because earlier in this thread, someone said you can't just bolt a square, "D" if you will, head and piston on an A/B bottom end, but it seems that's exactly what the "C" is, unless port timing has changed in the square cylinder for C/D variations.
So, with lower compression, I'll get higher revs? Yes?
Seeing as I have an extra crank laying around, does anyone know where I can get one of those xxx103xxx conrods to press in there just for kicks and giggles?
One other question... are all the cylidners 38mm bore? (forgot to measure that last night too). I feel like a lot of these engines had square cylinders when they were brought over here, seeing as that was standard in Europe and dealers just threw A/B cylinders on there. That would explain the square cylinder pistons (shorter ones, with different thickness rings) in non-square cylinder engines.
15mm Athena intake
Square port "D" cylinder w/ shorter piston
Larger ID header
Black $40 Jamarcol clamp on chamber