Here are some photos and measurements of the driveshaft and U-joint arrangement of the Honda CX650 models – and some GL650s/GL700s which appear to have the same 4-stud final drive arrangement. 4-stud here refers to the number of studs/nuts which affix the final drive to the swingarm.
It’s notable different to the driveshaft/U-joint arrangement of the CX500 models (3-stud final drive), which have both integrated into the one piece. Also note that while the CX650C has the same general component layout as the CX650E the U-joint and drive shaft are of different lengths. The below photos are of the CX650E items.
U-joint:
The CX650E drive shaft is part number 40200MG0000, CX650C part number 40200ME8003 (available new here at the time of writing). The CX650E unit is 170mm from end to end when it’s straight. As you might expect it has splines in either end, one for the final shaft coming out of the rear engine cover and one for the drive shaft forward end:
There’s also an “M” marked inside the U-joint:
This U-joint weighs in at 949gm.
The matching drive shaft (CX650E Eurosport):
The pointy end is the end that mates to the U-joint:
From the tip to the start of the shoulder where the splined section ends is 35mm. The final drive end:
The splines on this end are ~20mm long. You can see the stopper ring in place here, part number 40221-MG0-000 – and the oil seal (91261-ME9-005) which is available new here. It’s a 27x43x7mm seal.
The inside of the final drive end is a seat for a spring, not pictured. That spring is part number 40215-ME9-003 and is available new here.
Stamped into the pointy end is “FGO”:
The drive shaft is 350mm from end to end and weighs in at 985gm including the stopper ring and oil seal:
