Athena 85cc cylinder diameter 47,5 mm

Athena presents the new standard bore cylinder kit developed for Yamaha YZ 85 2019/2021.
This kit stands out from the OE one for some technical improvements, result of Athena's experience and know-how.

These refinements ensure extreme reliability and an optimal run.

All the components of the kit have been developed to resist at the highest temperatures, pressures and stresses
and are perfectly replaceable to the OE ones. The cylinder kit was also tested on the track and on the dynamic and
static bench to verify performance and quality.
This cylinder kit can be installed without any crankcase machining.

Engineered and produced entirely in Italy, the Yamaha YZ 85 cylinder kit has been been revised and developed
by Athena technicians to improve engine performance and efficiency:

CYLINDER WITH 6 STUDS
Compared to the original cylinder head, which includes 4
studs, Athena has studied and developed a head with 6
equally-spaced hub studs to distribute more evenly
the clamping load. This improvement avoids leakage
which could compromise engine performance.
The special stud on the exhaust allows for maximum
cooling, optimal thermal dispersion and perfect engine
efficiency.

MODULAR CYLINDER HEAD
The OE cylinder head, entirely in aluminum, was revised
and engineered by Athena R&D technicians by providing
an interchangeable dome, in order to ensure maximum
flexibility in customization and better performance.
The cylinder head, redesigned for the 6 studs, is made of
aluminum, while the central dome is manufactured from
bronze, which ensures better thermal stability even at
high temperatures.

PISTON WITH SINTERED COATING
Produced with cutting-edge computer technology, which
ensures dimensional tolerances of less than 0.01 mm,
Athena piston is made from gravity casting of high
quality materials which guarantee the same reliability of
the OE piston, while at the same time providing greater
resistance and excellent performance.
The piston has a special Molybdenum Disulfide sintered
coating to reduce friction, while the perfectly smooth
profiles ensure a perfect flame propagation.