At some point in the life cycle of the automatic cam chain tensioner engines Honda changed the design of the automatic cam chain tensioner body; you can see the newer hole location at the front of this pic (darker body tensioner), and the older design installed in the engine:
This new hole location is supposed to improve the tensioner’s internal lubrication, helping avoid the ball notching the plunger. The part numbers are slightly different amongst the models which have the auto tensioner;
| Model | Part No. |
|---|---|
| CX500 Turbo | 14500-MC7-000 |
| CX650E | 14500-MC7-000 |
| CX650 Turbo | 14500-MC7-010 |
| GL650, GL650I | 14500-MC7-010 |
| CX650C | 14500-MC7-010 |
At this stage we are unsure if the part number change relates at all to the change in hole location or whether it’s just a change in supplier or something else inconsequential to the design.