バインド頭 小ねじ - bind atama ko neji
The binding machine screw has a trapezoidal head and a rounded upper surface, and is characterized by a slightly larger head diameter than pan machine screws.
Bind machine screws are often used for general fastening like pan machine screws, but since the diameter of the head is large, they are also used in place of pan machine screws to prevent the seat surface of the fastened member from sinking.
Exact replacement for these OEM reference famillies:
Yamaha: 98580-xxxxx or 97885-xxxxx
Kawazaki: 220B-xxxx or 220AA-xxxxxx
Japanese vintage motorcycles, JIS screw, small head nut, small head bolt, pan head screw, honda, Kawasaki, Yamaha, Suzuki, Kawasaki 900 Z1, honda 750 CB K, Yamaha 350 rd, Suzuki 750 gt, zinc, stainless, acorn nut, black zinc, Japanese industrial standard, JIS screwdriver, engine bolt, flange bolt
JIS Screw Bind Head
Zinc is now called trivalent plating treatment which is a modern plating that looks similar to zinc without the chemical hazard and better consistency and corrosion resistance. This is the standard for Japanese manufacture and I recommend it for a perfect restoration.
Black aspect trivalent plating treatment which is a modern plating that looks similar to black zinc without the chemical hazard and better consistency and corrosion resistance. This replaces black zinc of early models and is now standard for Japanese manufacturers.
Yellow chromate treatment is a plating often found on small screws for carburetor or to give a rich aspect. Widely used in the 70s it has been replaced by trivalent zinc because of its environmental hazard.
Chrome platting is used for a beautiful mirror finish. However it is used only for very visible bolts, never seen for screws. Acorn nuts should have this chrome platting for a perfect reflection. If you like a highly polished look this is the finish to use.