Informational post for Learners, regarding #Yamaha #Rx bike engine #Bearings.
Bearings are a very basic unit of any engine, so should be taken VERY SERIOUSLY !
There are basically 2 types of bearings used in Rx Engine, one is Needle Roller bearing and other is Radial Ball bearing.
Total 7 bearings are there in engine (excluding 1 bigger end bearing in Connecting Rod)
2 ball bearings are used in crankshaft, 2 in Gearbox, 2 needle bearings are used in Gearbox shaft to crankcase joint and 1 needle cage bearing at piston wrist pin.
Some technical information:
Every ball bearing has some clearance between cage and balls, which is denoted by C and followed by a digit. Higher the digit, more the clearance. Clearance means, the amount of free space between the balls and cage.
Automotive bearings are heat treated, specifically crankshaft ones, those are treated with nitride, to withstand high operating temperatures, #SKF denotes heat treatment with HN3 coding.
Crankshaft automotive bearings (specifically where lubrication is done by oil pump) , has a broad and sharply inclined shoulder, to facilitate the proper oil flow from cylinder/transfer ports to bearings in crank via a piped hole.
Technical specifications :
Crankshaft radial ball bearings -
6304 C3 HN3 (Left side)
6205 C4 HN3 (Right side)
Gearbox bearings -
6304 CN (CN means standard/normal clearance)
6303Z CN ( Z means, metal shield as a seal at right side)
Gearshaft support bearings, needle roller -
NRB 152512 (Right nd left)
Piston wrist pin -
Cage needle roller ( specifications unknown to me, Yamaha oem is recommended)
There is one more bearing in bigger end of connecting rod, its specification is unknown to me. It usually comes with con rod as a set.
For more information, scroll down to Pictures and read captions.
- Sukhpreet Singh (admin panel)