Steering Neck Bearings
 

OEM Upper Bearing; Koyo 32907JR-3 1pc required
OEM Lower Bearing; Koyo 32907JR-2 1 pc required
OEM Outer Race; Koyo 32907JR 2 pc's required

Bearing Dimensions ID 35 mm OD 55 mm Width 11 mm

The OEM brand is KOYO. The upper bearing OEM part number is 92116-1074. The bearing is 32907 JR-3. The outer race is 32907 JR. The lower bearing OEM part number is 92116-1072. The bearing is 32907 JR-2.
The outer race is 32907 JR. As you can see both outer races have the same KOYO part number but the inner bearings have different KOYO part numbers. I am presuming that the shaft on the lower triple tree has two different dimensions at the top and the bottom ?

Thanks to Redjay for verifying the p/n's

PS; I have since found that the upper and lower bearings are the same size. The difference between the p/n's is that the 32907-JR3 upper bearing has a groove machined into the inner race for the O ring to sit in. Whereas the lower bearing does not have this groove.