Yamaha YZF-R3 Overbore +2mm “Turbo” Piston Kit 339.43cc 2015/Current

Description

Spears Racing Yamaha R3 2mm Turbo Piston Kit – Preferred Performance

The Spears Racing Yamaha R3 2mm Turbo Piston is a precision-engineered 3-ring FSR slipper-skirt forging designed for high-performance and professional competition use. Each piston weighs just 139 grams and delivers a 10.0:1 compression ratio, combining reduced reciprocating mass with strong power potential.

The dome features a smooth-flowing radius for efficient combustion, while under-crown machining removes unnecessary material to further cut weight without sacrificing strength. Anti-detonation grooves, accumulator grooves, and double-broach grooves provide added protection and ring stability under extreme heat and load. Valve pockets are 1 mm oversize and deepened to clear Spears Racing camshafts, and the overall design is lighter than OEM while adding measurable torque and rear-wheel horsepower.

This kit includes two pistons, two sets of piston rings, two lighter wrist pins, and four circlips, plus a detailed installation specification sheet. Every piston is produced on state-of-the-art CNC equipment to tolerances measured in millionths of an inch, using purpose-designed forgings developed through Spears Racing’s long manufacturing alliance with JE Pistons.

Spears Racing has spent decades refining race pistons through dyno testing and on-track championship success worldwide. Proprietary treated wrist pins and exclusive piston rings undergo rigorous development so the finished product exceeds the demands of serious competition.

Important installation notes
This 339.43 cc race piston kit requires the cylinders to be bored and re-plated with a Nickel Silicon Carbide (NSC) process. NSC plating is significantly more durable than factory plating and is the preferred choice of professional race teams for both rebuilt and brand-new OEM cylinders.

Spears Racing recommends surface-gap spark plugs for proper performance with these pistons:

• USA: NGK R0045Q-9 (replaces CR8E)
• European: NGK R0465B-10 (replaces LMAR8A-9)

Built for reliability under extreme conditions and engineered for real-world power gains, the Spears Racing Yamaha R3 2mm Turbo Piston Kit is the preferred choice for riders who demand championship-level performance.

See SP012-320-Guidlines-with-Information