| Year | 1999 |
| Date | 03-Dec |
| Volume | 183 |
| Issue | 4,108 |
| Page | 701 |
| Category | Stationary Engine |
| Part | 8 |
| Title | Harlequin & Hybriquin |
| Author | Mike Thurgood (South Africa) |
| Notes | Discusses design problems. Snap valve mechanism, inlet piston valves, trip levers, drop valve assembly, drive to valve chest, cylinder cladding |