Beyond Restoration: KAWASAKI Z1000J Custom by Yasuda Trading

Yasuda Trading's Z1000J

The Kawasaki Z made waves in the '70s with the debut of the first-generation Z1 in 1973. The Z underwent updates and transitioned to the Z1000J in '81 as numerous rivals emerged at the beginning of the '80s. This bike was customized by Yasuda Trading, known for handling many Honda CB-F series bikes, which were one of the rivals of the same generation. "Originally, this bike was acquired by the current owner from the previous owner. It had been customized a lot at the time it was given to him, but it was difficult to ride because of its age. So, we reworked it not only to ensure it was operational but also to enhance its safety for proper riding." This seems to be a common issue that many of the existing '80s models are facing and needs to be solved. We asked Mr. Yasuda about the key aspects, including the specific work that was carried out.

"First of all, we ensure that the parts which are stuck and not moving are freed, the joints are greased up, and any consumable parts are replaced. This was also the case with this bike. The front fork springs and rear suspension were worn out, so we replaced them. The brake system and the master cylinder also needed to be replaced. The same applies to the carburetor, which was a CVK from another model that was rattling, so we replaced it with a new FCR carburetor and set it up again. The engine was stock but proved to be okay, so we inspected the top half and replaced the gaskets." A standard black stainless steel megaphone exhaust was chosen, which closely resembles the stock one. "We utilized stock parts if available, and if not, we used custom parts. Some custom parts closely resemble the stock parts, so we selected and implemented them with a maintenance-oriented approach." As Mr. Yasuda says, there's a good reason for the stock-with-a-bit-extra look of this bike. In the past, Mr. Yasuda has always recommended that carburetors and brake parts should be replaced and refreshed after a certain amount of time. This J is a good example of applying the art of customization from a different angle to an '80s vintage model.

Handle

The meter with both mile/km display and the steering stem that clamps the ø38mm forks are stock North American-spec KZ1000J. The front master and clutch holder are taken from a current production model. It's also one of the updates.

Bodyworks

The round tank is also a stock North American KZ1000J, which came standard on the North American J1/J2 versions. The seat is also modified from stock.

Engine

The ø69.4 x 66mm 998cc engine was found to be in good condition, so an overhaul of the upper half was carried out for the upcoming future. Mr. Yasuda recommends a lower half overhaul and new harnesses, depending on the condition.

The CVK (negative pressure type) carburetor was rattling, so a new FCR ø35mm carburetor was installed and used with an air stream filter specification. It seems that even for custom bikes, replacing the carburetor with a new one improves performance, so it is recommended to consider this upgrade.

Chassis

The steps with a simple plate configuration are PMC S1-TYPE rearsets. This is also suited to the stock-like finish of the bike.

The ø38mm front forks are fitted with new springs and set up in combination with the rear suspension. The front single-piston calipers and discs are stock KZ1000J.

The rear calipers & discs are also stock, but the brake lines for both front and rear are stainless steel mesh. Consumables such as fluid are properly replaced.

The rear shock is replaced with a YSS to match the looks of the Z1000J and rebalanced. The 1.85-19/2.15-18 size wheels and round-tube swingarm are stock. The drive chain and sprockets are made by Sunstar.

Gallery

Specifications

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