This was an awesome engine in its time. NR was experimenting with piston materials and different crankshaft pin diameters. This one has the smallest pin diameter NR sold to the public. I don't recall if this one had a forged or cast piston. I was not very good at tuning and picking the right header/pipe combo when I ran this engine. But I got some pretty good finishes non-the-less. Roeloff can probably expand on my comments as he is in Europe and saw/used more of this engine than I.