Studs kit 7x155mm with rod for Vespa cylinders - MD RACING

M7 x 155 rolled studs in special nickel chromium molybdenum steel with heat treatment.

very high resistance to hot stretching,

strength 10.9 (100N / mm²).

EN 10204 - 3.1 certification

The kit includes 4 studs necessary to mount cylinders with a stroke greater than the original 51mm, or connecting rods longer than the original 97mm or under-cylinder bases to increase the phases.

Technical data:

The threaded part is M7 in 6g tolerance, while the central shank is 7mm in diameter against 6.2 / 6.3 of the standard rolled studs.

The greater section of the central shank produces benefits in terms of stability to stretch.

ATTENTION!!! The through holes on the cylinders for the M7 studs must be 7mm however in some cases such as QUATTRINI cylinders, the holes for the passage

they are made from 6.9mm instead of 7mm.

Before installing the cylinder, check that the stud slides freely on the dedicated hole.

To restore the correct passage, it is necessary to re-drill the holes with a 7 / 7.1mm bit before installing the thermal unit.

While for example for all cylinders FALC, PARMAKIT, Polini, Pinasco, Malossi etc. the M7 studs fit perfectly.

While for the POLINI cast iron cylinder there is even the opposite problem, that is, the holes are even 9mm

therefore being too large they cause the rotation of the cylinder once inserted in the crankcase, compromising the alignment of the transfer ports.