Description
Spears Racing High Compression Pistons FZ07/MT-07/R7 have been the piston of choice by several of the American Flat Track (AFT) teams and now most of the MotoAmerica roadracing teams.
The Spears Racing branded piston (Preferred Performance) 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.
Spears Racing’s High Compression Pistons FZ07/MT-07/R7 13.0 to 1 kit includes pistons, rings, lighter wrist pins, cir clips . The compression is 13 to 1. Dome features smooth flowing radius, under crown machining to lessen the overall weight. Anti Det. Grooves, Accumulator Groove, Double Broach Grooves for extreme applications including professional competition.
Spears Racing standard bore pistons are used by MP13/Cory Ventura race team, and has allowed numerous MotoAmerica Victories.
The compression ratio of these pistons is 13:0 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 FZ07/MT-07/R7 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
Piston Terminology for Spears Racing Pistons:
ANTI DETONATION GROOVES (CONTACT REDUCTION GROOVES) Also know as contact reduction grooves, which limit the piston/cylinder contact during high temperature and high RPM. These grooves also protect the top ring by disrupting detonation waves
ACCUMULATOR GROOVE V-shaped groove machined in the 2nd ring land that adds to the volume between the top and second ring. This groove accumulates residual gasses from combustion which alleviates top ring flutter and premature second ring wear, improving ring seal.
CP GROOVE CP Groove stands for Constant Pressure Groove. This groove is a channel on the lower part of the top land and equalizes pressure to the top ring groove. When used in combination with lateral gas ports, the CP groove helps keep gas ports clear of carbon build up. In addition, the CP groove prevents the top land from smearing into the top ring if the land rubs the cylinder bore.
DOUBLE PIN OILERS Double Pin Oilers (opposed to single pin oilers), in conjunction with our annular reservoir, can add twice the amount of oil from the cylinder wall to the wristpin bore. This is a standard option on any piston that receives forced pin oiling.
PIN FITTING The pin bore is precision honed to attain an exact pin clearance. Depending on the application clearances typically range from .0003 to as much as .003 between the wristpin and bore.
Cam and Barrel Extensive research and development has been done to find the optimum skirt shape for each piston. Having the correct cam and barrel on a part promotes the following:
1. Tighter clearances
2. Less noise
3. Better ring seal
4. More power
5. Durability
SERIALIZATION Each Spears Racing Piston is custom laser marking with the Part number, Job Batch and the Spears Racing Logo.
“Preferred Performance” Pistons Kits By Spears Racing
Spears Racing’s High Compression Pistons FZ07/MT-07/R7 kit 13.0 to 1 Includes the Following:
Large Valve Pockets for 1mm over valves
Pistons x 2
Wrist Pins x 2
Piston Rings x 2
Cir Clips x 4
Piston Weight:212 grams
Detailed install specification sheet.
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