

Roller tappets, bucket tappets, piston pins and forks
THE TAPPET: WHAT IS IT AND HOW DOES IT WORK?
The tappet is positioned between the valve and the system that controls it (camshaft or rocker arm) in order to adjust the clearance and, if necessary, self-adjust; depending on the type of tappet, it is possible to set a different lift of the valve and the way in which the forces are distributed.
Tappet means the set of mechanical elements positioned between the camshaft and the valve of an internal combustion engine. These elements transmit the rotating movement of the camshaft, transforming it into the alternating linear movement of the poppet valve, thus controlling its opening and closing.
The system enables adjustment of the tolerance clearances of the various components due to the thermal expansion of the materials used, caused by the engine’s changes in temperature, prevents the valves from bending under the action of the cam and eliminates interference between the command and control elements.
There are several difference types of contact surfaces (bucket tappet) with the camshaft:
- Flat faced: this is the standard configuration where the contact surface with the cam stretches from one side of the bucket tappet to the other
- Spherical faced: the base of the bucket tappet, instead of being flat, is spherical or has a wheel that enables a different control to that of the flat bucket tappet because the contact surface remains more central, which leads to more rapid control compared to the flat faced bucket tappet and allows for the use of shorter valve timings with the same lift; moreover, if a wheel is used, it is possible to reduce friction and wear, in the case of indirect control, this device is moved onto the bucket tappet.
- Knife edged, similar to the wheel, but is more stressed
PISTON PINS
The piston pin is the pin that enables kinematic coupling with the piston rod in the piston.
FORKS
One of the components needed for the functioning of the gearbox are the forks that are usually mounted on the selector drum of the gearbox; that is, the device used on front coupling gearboxes that, controlling them, allow the forks to move the gears of the gearbox and determine the travel.

DLC
Gentilini has developed a coating system for the racing sector, and manufactured it in liaison with a specialised company, that improves sliding between the camshaft, rocker arms, bucket tappets, tappets, etc... This coating system is called DLC.
APPLICATIONS OF DLC
- Components subject to sliding and high abrasive wear
- Camshafts, tappets, pin pistons, bucket tappets
ADVANTAGES OF DLC
- Surface hardness from 1800 to 2600 HV
- Friction and sliding coefficient around 8 times lower than that of Steel/Steel
- This reduces wear, improves performance and increases the life of the components
- It meets the requirements of the intracutaneous reactivity test in accordance with standard ISO 10993-10:2010
- ALL ENGINE MANUFACTURERS ARE MOVING TOWARDS THIS TYPE OF COATING TO INCREASE PERFORMANCE AND REDUCE CONSUMPTION AND EMISSIONS.
MARKETS OF INTEREST

MOTORCYCLES – RACING/MOTOGP/SBK

MOTORCYCLES – RACING OFF ROAD

SCOOTER

MOTORCYCLE

TRIAL

RALLY

AIRCRAFT ENGINE PRODUCTS

NAUTICAL

DIESEL – GENERATORS
Roller tappets, bucket tappets, piston pins and forks
THE TAPPET: WHAT IS IT AND HOW DOES IT WORK?
The tappet is positioned between the valve and the system that controls it (camshaft or rocker arm) in order to adjust the clearance and, if necessary, self-adjust; depending on the type of tappet, it is possible to set a different lift of the valve and the way in which the forces are distributed.
Tappet means the set of mechanical elements positioned between the camshaft and the valve of an internal combustion engine. These elements transmit the rotating movement of the camshaft, transforming it into the alternating linear movement of the poppet valve, thus controlling its opening and closing.
The system enables adjustment of the tolerance clearances of the various components due to the thermal expansion of the materials used, caused by the engine’s changes in temperature, prevents the valves from bending under the action of the cam and eliminates interference between the command and control elements.
There are several difference types of contact surfaces (bucket tappet) with the camshaft:
- Flat faced: this is the standard configuration where the contact surface with the cam stretches from one side of the bucket tappet to the other
- Spherical faced: the base of the bucket tappet, instead of being flat, is spherical or has a wheel that enables a different control to that of the flat bucket tappet because the contact surface remains more central, which leads to more rapid control compared to the flat faced bucket tappet and allows for the use of shorter valve timings with the same lift; moreover, if a wheel is used, it is possible to reduce friction and wear, in the case of indirect control, this device is moved onto the bucket tappet.
- Knife edged, similar to the wheel, but is more stressed
PISTON PINS
The piston pin is the pin that enables kinematic coupling with the piston rod in the piston.
FORKS
One of the components needed for the functioning of the gearbox are the forks that are usually mounted on the selector drum of the gearbox; that is, the device used on front coupling gearboxes that, controlling them, allow the forks to move the gears of the gearbox and determine the travel.

DLC
Gentilini has developed a coating system for the racing sector, and manufactured it in liaison with a specialised company, that improves sliding between the camshaft, rocker arms, bucket tappets, tappets, etc... This coating system is called DLC.
APPLICATIONS OF DLC
- Components subject to sliding and high abrasive wear
- Camshafts, tappets, pin pistons, bucket tappets
ADVANTAGES OF DLC
- Surface hardness from 1800 to 2600 HV
- Friction and sliding coefficient around 8 times lower than that of Steel/Steel
- This reduces wear, improves performance and increases the life of the components
- It meets the requirements of the intracutaneous reactivity test in accordance with standard ISO 10993-10:2010
- ALL ENGINE MANUFACTURERS ARE MOVING TOWARDS THIS TYPE OF COATING TO INCREASE PERFORMANCE AND REDUCE CONSUMPTION AND EMISSIONS.
MARKETS OF INTEREST

MOTO – RACING/MOTOGP/SBK

MOTO – RACING OFF ROAD

SCOOTER

MOTORCYCLE

TRIAL

RALLY

AIRCRAFT ENGINE PRODUCTS

NAUTICO

DIESEL – GENERATORI
How we work
Since 2008 the group has been developing new components for leading companies in the two-wheeler sector and continuing to develop and expand its interests more and more.
The close-knit team of technicians and engineers collaborates in synergy with industry experts , to find valid and concrete solutions in every area.
In making our products, the search for the best raw materials is accompanied by a careful selection and control of treatments (especially necessary for the nautical market)
