Head and Valves - Honda CX and GL
Twisted at 22 degrees from the centerline, the CX/GL heads have four valves per cylinder. Scroll down to read the articles.
Twisted at 22 degrees from the centerline, the CX/GL heads have four valves per cylinder. Scroll down to read the articles.
The Honda CX and GL V-twin family have their cylinder heads twisted 22° from the crankshaft centerline. This has a couple of advantages; the carburetors are pushed further inward and out of the way of the rider's knees and the weather. Additionally, it pushes the exhaust headers out away from the centerline, meaning that they exit neatly on either side of the radiator.
The twist in the heads does mean that the pistons have a 22-degree twist in the piston crown to match, and that Honda chose to use pushrods rather than a more expensive - and technologically challenging to implement - gear arrangement for the camshaft drive which would have allowed the use of a OHC (overhead camshaft) setup.
One of the great advantages of the CX/GL's engine layout is that any attention to the heads does not require removing the engine from the frame; everything is readily accessible with only removing the seat and tank.
| Item | Specification | Service Limit |
| Compression | 171psi, +/- 28psi @ 700rpm | Below 120 = investigate |
| Valve seat width | 1.1-1.3mm 0.04-0.05" |
2.0mm 0.08" |
| Head warpage | 0 | 0.10mm 0.040" |
| Valve spring free length | ||
| Intake, inner | 50.3mm 1.9803" |
48.4mm 1.9055" |
| Intake, outer | 50.4mm 1.9842" |
48.5mm 1.9094" |
| Intake, outer | 50.4mm 1.9842" |
48.5mm 1.9094" |
| Exhaust, inner | 50.3mm 1.9803" |
48.4mm 1.9055" |
| Exhaust, outer | 50.4mm 1.9842" |
48.5mm 1.9094" |
| Valve spring free length |
More info on these to come...
