Zip-Ty Racing Fuel Mixture (Pilot) Screw
The Zip-Ty Racing carburetor fuel mixture screw replaces your carburetor's stock pilot screw. On the Keihin FCR carburetor, the stock screw is recessed on the bottom of the carburetor next to the drain bolt. Because of its location, adjustment is extremely difficult, if not impossible, without an angled screwdriver or other makeshift tool.
On the engine side of the float bowl drain bolt, the pilot screw (idle fuel mixture screw) is visible in its recess.
The Zip-Ty screw extends beyond the recessed hole and provides a knurled knob allowing adjustment on the trail without any tools! No modification to your carburetor (filing or grinding) is required unlike some other replacements. The Zip-Ty screw also features numbered index marks which make it easier to keep a log of your adjustments.
The fuel screw is available for Keihin FCR carburetors and some 2-stroke Mikuni carburetors. At the time I wrote this, this does not include the California street-legal DR-Z400S which is outfitted with a Mikuni carburetor. Off-road DR-Zs (400 and 400E) utilize the Keihin FCR.