Kawasaki begins manufacturing reproduction Z1 cylinder heads

The importance of the secondary motorcycle market was acknowledged this week when Kawasaki announced it has begun manufacturing reproduction cylinder heads for its milestone Z1 900cc motorcycle from the 1970s.

The Z1 was the first liter-class Japanese superbike and became an icon during the baby-boomer-induced motorcycle sales bonanza of the 1970s, with more power than any previous production motorcycle and a DOHC four-cylinder engine so strong that its 81 horsepower was often doubled before reliability issues set in.

Just 18 months shy of its 50th birthday, the now classic Z1 is being restored to showroom condition in such significant numbers that Kawasaki has created a reproduction Z1 cylinder head using current production methods, meaning that although it is based on original design plans and specifications, it is actually of better quality than the original.

Kawasaki’s release states that the new cylinder head is “not intended to be an exact copy of the original, including the shape and surface quality, based on production standards at the time.”

With the Kawasaki Z1 soon to turn 50 years of age, auction prices for concours restorations of the Z1 have surged past the US$20,000 mark and Bonhams now holds the record price for a perfectly restored Kawasaki Z1 at £28,175 ($36,792) with the price expected to continue to climb over the coming years.

That’s because although over 80,000 units were sold of the Kawasaki 900 Mk 1 series globally between 1972 and 1975, exact numbers of the original Z1 model have never been made available and that’s the most collectible (and valuable) model of the series. Some sources believe the actual numbers of the Z1 were as low as 8000 units globally, while engine numbers peg the maximum number that could have been produced at 20,000.

Regardless, because the Z1 engine was the first “bulletproof” motorcycle powerplant available to the public, and the frame and suspension were comparatively weak, there were very few of the original bikes that didn’t get extensively modified, so even if Kawasaki used all of the 20,000 engine numbers available to it, most have been modified, raced, crashed, butchered and blown up.

Given the high attrition rate, it’s unlikely there are many more Z1 models out there that are still in original condition, perhaps even less than the 7,414 production run of the original Honda CB750 “sandcast” and that model has been selling for more than $30,000 for many years.

As auction prices are subject to the laws of supply and demand, that makes the Z1 a collectible motorcycle that will appreciate in value for the foreseeable future – a rare combination of utility and financial prudence that is quite capable of tickling the adrenals and stretching your arms.