Recommended Regular Maintenance (Sunbeam)






  1. Oil – the engine oil capacity of Sunbeams is relatively small, more so on early S7s and less so when a sump extension is fitted. Regular checks of the oil level is a wise precaution but don't over-fill. Good quality SAE50 mono-grade mineral engine oil is most popular. A full oil change is advisable annually or after about 2K miles, whichever occurs sooner. (Refer to the separate sheet for running-in.)

  2. Tyre pressures – tyre pressures can affect handling significantly and even dangerously. Preferences differ but I run S8 tyres at 36psi and S7 tyres at 30psi. Using higher pressures reduces drag and sharpens the handling, particularly on S7s.

  3. Cables – cables can last a long time but they don't last forever. Failures are inconvenient, can be dangerous and are avoidable. Lubricate them regularly and they work better and last longer. Look for fraying of the inner cable near the ends and damage to the casing that can let water in. Smooth curves are best – sharp curves increase friction and shorten cable life.

  4. Engine oil leaks – Sunbeams can be prone to oil leakage, even when the gaskets and seals are in good condition. It is usually a result of increased crank-case pressure. Worn engines tend to have more crank-case pressure, owing to increased 'blow-by' of combustion gasses. Poor engine breather performance is often the cause. Check that air is freely expelled from the breather when the engine is idling. If you have an enclosed breather cover, occasionally check that air cannot pass back into the breather by blowing onto the pipe. The breather is a one-way valve so air should flow out freely but be prevented from flowing in. The breather pipe (where fitted) should be as short as possible and free of constriction.

  5. Tightening engine fasteners – it is good to keep fasteners tight but don't be tempted to over-tighten them in a desperate attempt to cure an oil leak. Over-tightening can distort casings, pull threads and make leaks worse. Instead look for the real cause, e.g. breather malfunction, a failed seal or a damaged gasket.

  6. Transmission oil – keep the oil in the gearbox and the rear drive topped-up to the level plug but never over-fill them. Leave the level plug open for at least 1/2-hour after filling, to make sure that the oil level is correct. It is OK to use engine oil in the gearbox but SAE90, GL-1 gear oil works at least as well. The rear drive requires a more viscous oil. Most people use SAE140, GL-1 to GL-3 gear oil. Under no circumstances use any gear oil rated higher than GL-3 in either the gearbox or the rear drive because the additives will 'eat away' the expensive bronze components.

  7. Spannering – is the process of checking the whole bike regularly for loose fasteners. Over-time, fasteners can vibrate loose or they can be accidentally left loose after maintenance. Frequent spannering is good practice to improve safety but it can also prevent the loss of parts that are expensive to replace. Doing it after washing the bike can also lead to the early discovery of poor adjustment or failing components.

  8. Brakes – check brake shoes at least annually for wear or oil contamination. Where present, keep the fulcrum cones adjusted properly for optimum brake performance. Loosen the cable adjuster and turn the fulcrum adjuster clock-wise until the shoes just start to bind then back them off by one click. Then adjust the cable to your requirements.

  9. Synthetic oils – those owners who understand advanced oil specifications can use appropriate modern synthetic oils for better performance and longer life. But check carefully the additives and recommended usage, to avoid damage.