GT-3B Needle Bearing Failure

[Riding Rich]

Well iv'e heard the clik click for a wile now.

I orderd 2 13x14x13 needle bearings for a Sthil 028 chainsaw so i figured i'd use the stock PK bearing in the Grubee for a wile.

Now when i pulled the Bearing 4 needles fell out of the cage.
It was getting close to catastropic.
Notice the rings worn into the rollers at the ends where they sit in the cage.

And the size difference in the PK80 and Grubee 48 stock bearings.
The PK is 13MM wide the Grubee is only 10MM wide.

I will have comparison when i get the Sthil bearings but iv'e heard there rated for 13000 rpm.
Thats plenty to spare.

Also note i have about 2000 miles of 6000 / 8000 rpm riding on it.

And yes i did this with the motor in the bike but i have sealer for base gasket.

 

[Riding Rich]

You will need to remove one stud to get the piston out.

Here's the pics of the bearings

 

[Riding Rich]

BTW

This is a Grubee GT-2B 48cc not 3B.

My Bad