Okay so after the month long ride I'm finally home. I've crossed 44,000 kms and won't be riding in the coming two months due to peak summers. So I took the bike apart for maintenance, including my first valve clearance check (will post about that in another thread). I've taken the radiator off the bike to make the access to the valve cover very easy.
Sooooo while I was inspecting the radiator, I turned the radiator fan by hand and it made a rather squeaky noise. I was surprised and took the fan off the radiator. After taking the fan blade assy off, I directly turned the shaft and could completely feel that the movement was coarse and not seamlessly smooth. So I decided to open the fan if I could and see what's the problem.
The fan blade assy is bolted to the motor shaft with a 8mm locknut.
Once the fan is off you need to take off the three screws off the fan housing. In this picture I've replaced them with Hex Key bolts as I had to cut the original Philips bolts as they had rusted and would not come out.
The housing can be pried open by sliding flat head screwdrivers under the lip of the fan motor housing. The magnet is quite strong and it's not that easy to take off. There is no glue or any other locking mechanism so no need to worry about breaking something.
Once the housing is open there are three parts. First would be this part, the front housing which houses the bearing right behind the fan blade assy.
This is the motor commutator/winding. There's plenty of black dust from the motor bushings all over the inside of the motor asst which I cleaned up.
The original bearing is on the other end of the shaft.
The other casing houses the magnet, bushes and a copper like O ring which sits between the 2nd bearing and housing.
Bearing no is 608 Z. Two bearings cost me $3.00. While the inner bearing on the end commutator shaft was fine I replaced both the bearings anyway.
New bearing installed and the fan assembly was put back together. Now it runs smoothly and slick.