KTM RC390 standard bore (89mm) high compression race piston by Spears Racing has a new 3 Ring FSR Slipper Skirt forging Piston. This kit includes piston, rings, Tapered lighter wrist pins, cir clips . The compression is 13.0 to 1. This design is lightest piston which comes with deeper pockets to allow the Racing Camshafts to fit with this new design. Each piston dome is brushed to remove any and all sharp edges.


Spears Racing KTM RC390 standard bore (89mm) 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 standard bore (89mm) high compression race piston has a special under-crown machining to reduce the weight to be closer to the OEM Piston weight.

KTM RC390 373.2 cc Piston 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 Nitrided 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.

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.



KTM RC390 373.2cccc 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)