KTM RC390 OVERBORE ENGINE KIT (91mm) HIGH COMPRESSION RACE PISTON 13.0.1

Description

Spears Racing KTM RC390 2mm overbore engine kit (91mm) high compression race piston has a compression ratio of 13.0 to 1.  Spears Racing has been designing and making race pistons with the State of the Art CNC Machining and manufacturing alliances with JE Pistons for decades. Spears Racing continuous committed to excellence to advance as the industry changes. This commitment has resulted in more forgings specific to certain applications, proprietary treated wrist pins and piston rings manufactured only for us. Each of these aspects has been put through stringent research and development stages to ensure that our product will exceed your standards. The Spears Racing  KTM RC390 2mm overbore  (91mm) high compression race piston has a special under-crown machining to reduce the weight to be closer to the OEM Piston weight.

Spears Racing KTM RC390 2mm overbore engine kit: This is the new 3 Ring  asymmetrical FSR Forging made for Spears Racing by JE Pistons. This race piston  kit includes piston, rings (Steel Gas Nitride Barreled Faced), lighter tapered wrist pins, cir clips . The compression is 13.0 to 1. At the forefront of performance, piston manufacturing has been a result of continuous research and development of unique materials, piston designs and technologies. Utilizing State of the Art CNC machines for manufacturing, along with purpose-designed forgings, while being able to maintain exacting specifications on each and every piston – holding tolerances to millionths of an inch. This is the new forging that is lighter Pistons.

Dual Velocity Gas Porting:

Dual Velocity Gas Ports are the combination of the two traditional gas ports, bringing you the best of both worlds. Our patent-pending design brings positive gas pressure to the back side of the top ring, without a gas port that will clog from carbon build-up.

Je Team did back-to-back testing allowed us to analyze differences in blow-by, horsepower, and torque. The results showed a 2% increase in peak horsepower and torque when using the Dual Velocity Gas Ports.

• Heat Reflection: Rejects combustion heat, reducing thermal stress on the piston crown.
• Prevents Annealing: Minimizes material softening, extending piston lifespan indefinitely under proper conditions.
• Boosts Efficiency: Reflects heat into the combustion chamber, improving exhaust gas velocity and power output.

• Anti-Detonation Grooves: Reduce piston-cylinder contact at high temperatures and RPMs, protecting the top ring from detonation waves.
• Accumulator Groove: V-shaped groove between top and second rings reduces ring flutter, improving seal and longevity.
• Double Pin Oilers: Deliver twice the oil to the wrist pin, enhancing lubrication and durability.
• Precision Pin Fitting: Honed pin bores with clearances from 0.0003” to 0.003” for optimal performance.
• Optimized Cam and Barrel: Custom skirt shapes ensure tighter clearances, less noise, better ring seal, and increased power.
• Custom Laser Marking: Each piston is serialized with part number, batch.

Nickel Silicon Carbide (NSC) plating service includes:

The Cylinders are proprietary Nickel Silicon Carbide (NSC) cylinder plating process and cylinder services. This NSC process is so superior to factory plating that Millennium Technologies is often used by professional race teams all over the world to re-plate brand new OEM cylinders. Millennium stands behind their plating with a LIMITED LIFETIME WARRANTY.

Modern engine designs use very light aluminum cylinders. The aluminum base metal is very soft and would wear out almost instantly without a very special protective barrier. The Millennium Technologies Nickel Silicon Carbide (NSC) cylinder plating process forms an extremely hard, extremely durable barrier with less friction, improved heat transfer, less weight, and ultimately more horsepower.

 Spears Racing Piston Kits have been winning races and Championships all over the world for over 4 decades. Spears Racing pistons have been in several of the race wins in close course racing and in road circuits in Europe and has won the Isle Of Man TT Twins several times.

“PREFERRED PERFORMANCE” PISTONS KITS BY SPEARS RACING”

KTM RC390 390.23cccc Pistons Includes the Following:

Piston Weight: 271 Grams (This piston is lighter than other companies currently on the market)