Description
Spears Racing has been designing and making race pistons for decades, their continuous committed to excellence to advance as the industry changes. This commitment has resulted the new High Compression Pistons Yamaha 320 design with 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.
This is the new 3 ring, forged Piston. Standard bore high compression kit includes pistons, rings, lighter wrist pins, cir clips . The compression ratio of these pistons is 13.5 to 1.(We recommend the use of OEM Yamaha Head gasket) Dome features smooth flowing radius, under crown machining to lessen the overall weight. Anti Det. Grooves, Accumulator Grooves, Double Broach Grooves for extreme applications including professional competition. These pistons also have had the domes (tops) of each unit brushed ,this will insure that all of the sharp edges of the dome and not creating more heat in the combustion chamber.
Thermal Barrier Crown Coating
Heat is a major reason for decreasing a piston’s lifespan. JE has developed a proprietary ceramic gold crown coating that is applied in-house and rejects a large portion of the damage-causing heat piston crowns are subject to.
“Typically”, a piston gets annealed, or softens, over time due to heat cycling. The crown of the piston pulls a lot of heat into it. At some point there is a life cycle to aluminum. The softer the piston gets, the more it will take on an umbrella shape. Then comes end of life
When all things are operating properly in the engine, the ceramic gold coating gives the crown virtually an unlimited lifespan without any issue of the piston annealing.
Applied to the top of the piston and is designed to reflect heat into the combustion chamber, thereby increasing exhaust gas velocity and greatly improving scavenging potential. The .0015” thick coating can also assist in extending piston life by decreasing the rate of thermal transfer.
Spears race pistons with the State of the Art CNC Machining and manufacturing alliances with JE Piston 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.
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
Spears Racing High Compression Pistons have been winning races and Championships all over the world, this piston designs makes more than the Factory Pistons. Spears Racing pistons have been in several of the race wins in close course racing and in road circuits in Australia, Europe, North America, South America South Africa and has won the Isle Of Man TT Twins multiple times.
“Preferred Performance” Pistons Kits By Spears Racing
The Yamaha 320 piston kit design is lighter than OEM and comes with 1mm o/s valve pockets and deeper pockets to allow the Spears Racing Camshafts to fit with this new design.
These pistons have large enough valve pockets to work with Spears Racing SP17-320 camshafts
Several of these kits have been sold to racers and teams all around the world, teams in the Philippines have been racing with these for several months and love the difference in the off the corner torque and the new top RWHP.
Spears Racing recommends using a surface gap spark plug when installing these pistons, You will need to look at your current spark plugs USA NGK CR8E (recommend using NGK R0045Q-9 ) European NGK LMAR8A-9 (Recommend using NGK R0465B-10 )
Yamaha R3 Standard Bore Race Piston kit High Includes the Following:
Large/Deeper Valve Pockets for 1mm over valves
JE Pistons(3 Ring Pistons)
Weight:134 g per piston
Pistons x 2
Wrist Pins x 2
Piston Rings x 2
Cir Clips x 4
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