Tighten each nut down until the underside of the head is 1/8″ away from the top of the spring cup. The final adjustment of individual spring pressure is best done with the engine back in the bike and with the clutch cable attached, as the pressure plate has to be lifted and the engine turned over to view the edge of the pressure plate.
Turn the engine over with the clutch lifted and look at the edge of the pressure plate to see if it wobbles as it rotates.
Tighten down the nut nearest to where it is highest by half a turn at a time and after each adjustment release and lift the pressure plate before rotating it again. Continue until the pressure plate lifts evenly.
Next check if the is any clutch slip when turning the engine over against compression. Tighten each of the four nuts by half a turn at a time until the slippage is stopped.
The oil in the engine serves various functions, it lubricates the moving parts, cools & transfers heat and cleans the engine. There are basically three types of oil available: Monograde, Multigrade and Synthetic, the former being the oldest. The first two are Mineral based oils with varying characteristics.
A measurement of the oils ability to flow is called viscosity, and this is shown on the can as a figure. This is measured at normal working temperatures, so a monograde will be a lot thicker when it is cold. To get around this thinner oils could be used in very cold climates or during winter periods. A modern Multigrade oil has additives that stop the oil thinning as quickly as a straight oil as it gets hot, so it gives better protection at all temperatures.
Technically, a modern Multigrade oil at 0 degrees Celsius the oil viscosity rating is compared to an equivalent straight oil’s viscosity and similarly, at 100 degrees Celsius, it is again compared to a straight oil’s viscosity at 100 C.