Bike has more that 300hrs.
Since I got the bike, did 2.000 kms on it. Ride mostly slow stuff, but don't hesitate to pin it.
Short time after purchase, 1 year ago, I noticed free play on ignition side.
https://www.youtube.com/watch?v=gqW0FSZ51Ow (crank the speaker volume from 0:35 onward)
Some mecs said its no big deal, so I rode it normally and checked every ride, if it had gotten any worse, but it didnt.
In recent times, cold bike starting took longer than 1 - 2 kicks.
Also was loosing a lot of bottom end torque, especially in tight stuff, when heat generation was higher, so I decided to tear the engine completely, re-piston and re-bearing it, and while at it, drop in checkpoint offroad's alu impeler and 80mm server fan on rectified DC, to make things cooler.
Installed was wossner piston "B", which should be 71.94. Through use, it was beat to 71.88, while bore was measured at 72.02.
Piston replacement just came in today, wossner C, or 71.95.
Main bearings were probably never replaced. Units were balled and sealed SKFs, Italy C4 ignition side, India C3 clutch side.
While clutch side bearing was in excellent condition, ignition side also had no visible deterioration, except for increased radial play.
Original bearings are, due to current gasgas insolvency undeliverable, and tad pricey.
You can get ordinary skf 62/28 C3, but you can't get C3HN3 version.
Also, you can get 6206 in C4, but you can't get ITN9/C4GJN version.
Surfing resulted in:
62/28 C3HN3 (clutch side)
- 62/28:...........size
- C3:...............clearance
- HN3:.............W18Cr4V (Rings, rolling elements, made of hardening bearing steel)
6206 ITN9/C4GJN (flywheel side)
- 6206:...........size
- (I?)TN9:.......polyamide plastic cage
- C4:..............clearance
- GJN:.............Bearing with high temp grease -30 to +150 ?C
The only thing worth worrying about, when buying (high quality) replacement bearings in the local store, is to get the HN3 suffix.
Since I will remove seals from bearings, there is no need for GJN, or grease.
Also, polyamid cage TN9 can be replaced with steel one.
There are + and - for using each type, like:
steel has longer life, but if disintegrates, cylinder, piston etc is toast.
plastic has less rotating mass and can run with lessened lubrication, but it's running life is supposed to be shorter.
There is a prolongued waiting time on C4 plastic cage bearings. Still, would rather use plastic.
That's it for now.
Since I got the bike, did 2.000 kms on it. Ride mostly slow stuff, but don't hesitate to pin it.
Short time after purchase, 1 year ago, I noticed free play on ignition side.
https://www.youtube.com/watch?v=gqW0FSZ51Ow (crank the speaker volume from 0:35 onward)
Some mecs said its no big deal, so I rode it normally and checked every ride, if it had gotten any worse, but it didnt.
In recent times, cold bike starting took longer than 1 - 2 kicks.
Also was loosing a lot of bottom end torque, especially in tight stuff, when heat generation was higher, so I decided to tear the engine completely, re-piston and re-bearing it, and while at it, drop in checkpoint offroad's alu impeler and 80mm server fan on rectified DC, to make things cooler.
Installed was wossner piston "B", which should be 71.94. Through use, it was beat to 71.88, while bore was measured at 72.02.
Piston replacement just came in today, wossner C, or 71.95.
Main bearings were probably never replaced. Units were balled and sealed SKFs, Italy C4 ignition side, India C3 clutch side.
While clutch side bearing was in excellent condition, ignition side also had no visible deterioration, except for increased radial play.
Original bearings are, due to current gasgas insolvency undeliverable, and tad pricey.
You can get ordinary skf 62/28 C3, but you can't get C3HN3 version.
Also, you can get 6206 in C4, but you can't get ITN9/C4GJN version.
Surfing resulted in:
62/28 C3HN3 (clutch side)
- 62/28:...........size
- C3:...............clearance
- HN3:.............W18Cr4V (Rings, rolling elements, made of hardening bearing steel)
6206 ITN9/C4GJN (flywheel side)
- 6206:...........size
- (I?)TN9:.......polyamide plastic cage
- C4:..............clearance
- GJN:.............Bearing with high temp grease -30 to +150 ?C
The only thing worth worrying about, when buying (high quality) replacement bearings in the local store, is to get the HN3 suffix.
Since I will remove seals from bearings, there is no need for GJN, or grease.
Also, polyamid cage TN9 can be replaced with steel one.
There are + and - for using each type, like:
steel has longer life, but if disintegrates, cylinder, piston etc is toast.
plastic has less rotating mass and can run with lessened lubrication, but it's running life is supposed to be shorter.
There is a prolongued waiting time on C4 plastic cage bearings. Still, would rather use plastic.
That's it for now.
