Regrettably, the quality of the crankshaft bearings is often underestimated when it comes to motor tuning projects. This is in spite of the fact that the crankshaft that they support is one of the hardest working components of the two-stroke motor!
To help remedy this MALOSSI have, in collaboration with the engineers at SKF, developed a range of high-performance ball-bearings. To easily satisfy the highest standards they are constructed using needle-bearing grade stainless steel. The main differences to other bearings produced by SKF for scooter motors are the larger diameter bearing rollers and the partially carbon-nitrated inner ring. These features lead to a smoother running motor, especially noticeable at high revs. High revving motors can fail prematurely due to excessive heat expansion of standard grade bearings. The MALOSSI bearings are available with a standard internal bearing clearance (CN) and also C3 and C4 (larger than standard internal clearance) grades. These items are, in the most cases, equipped with a polyamide bearing cage but sometimes possess steel or brass cages.
MALOSSI bearing code guide :
STD = Standard internal bearing clearance (CN).
C3 = Larger than standard internal bearing clearance with polyamide cage.
C4 = Larger than C3 internal bearing clearance, with polyamide cage.
C3H = C3 internal bearing clearance, with a pressed and tempered steel-plate snap-cage.
C3M = C3 internal bearing clearance, with a ball-bearing base construction and brass cage.
TN9 = Bearing cage made of polyamide.
ETN9 = 'E' signifies a modern style of construction.
SIP-TIP : Do not forget to order the suitable PTFE crankshaft oil-seals, also produced by MALOSSI!