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

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.

• 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:

evaluation
stripping
NSC plating
diamond hone finish

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 x 1
Tapered Wrist Pin x 1
Piston Rings x 1
Cir Clips x 2

Piston Weight: 258 Grams (This piston is lighter than other companies currently on the market)