Hi to all,Best to check the factory manual, but I think the cylinder studs should be a bit under 20Nm, tighten in a circular pattern from the middle (best as in manual) and best do it in steps (tighten to 10Nm, then 15Nm, then ~18Nm final torque). A few days and heat cycles, then I'd untighten and retighten (18Nm is not a lot of torque, the gasket compresses and the nuts sit into the head with a few cycles... best retighten to make it hold consistently). Very important to thoroughly clean the threads and then lubricate the threads and the nut with engine oil very well! Without oil, the clamping force will be ~30-40% lower!
CB350 manual only specifies the torque. However, they forgot to note it. CB350 head stud uses an M8x1.25 fastener. At 180kg cm, that's around 17Nm. The standard max torque for M8x1.25 for 8.8 grade screws is 25Nm (this value is on the "safe" side and rounded downwards and it gives repeatable results) for dry threads - 255kg cm. Force increase with using 15w30 engine oil is around 30-40% (graphite would be even a bit more). 30% off of 25Nm is 17.5Nm or right around 180kg cm!I thought that Honda required (unless specifically specified) that when torquing nuts / bolts that the threads be dry