Oil right on the night!

It would depend upon how often you change your oil. Most of the oils recommended in the Riders' Handbooks and Manuals for our bikes are no longer available anyway. I haven't seen any Castrol XL 30 for a very long time.

You can still get Castrol XL funnily enough. Some of the new, thin oils of SG and higher specifiction are formulated to satisfy emmissions requirements. Some of the Classic oils at least claim to be formulated for older engine materials and technology with zinc based anti-friction additives. This type of discussion has raged ever since oils were first used. There is no right answer...

There are numerous threads on this forum about oil. Either use a 20:50 or a monograde. It doesn't matter a jot, as long as you change it every 5 years or so.

Previously wrote:

You can still get Castrol XL funnily enough. Some of the new, thin oils of SG and higher specifiction are formulated to satisfy emmissions requirements. Some of the Classic oils at least claim to be formulated for older engine materials and technology with zinc based anti-friction additives. This type of discussion has raged ever since oils were first used. There is no right answer...

As a point of fact, friction modifiers are not zinc based and friction modifiers are only used in low viscosity oils. The Zinc compounds, Zinc di- alkyl- dithio phospates,(ZDDP's), function as both anti-oxidants, preventing thermally induced viscosity increase, and as anti wear agents by forming elastic glass like films at cam/ follower interfaces. ZDDP's actully form films which have high coefficients of friction. It is for this reason that Mo additives which, at surfaces, form Molybdenum disulphide and organic friction modifiers, esters, are used to reduce friction and improve fuel efficiency in low viscosity oils.

Classic oils are all very well and are a lucrative niche market but their performance claims, SE SG etc cannot be substantiated.

Please don't leave your oil changes for 5 years you may live to regret it!

Previously wrote:

Cheapest modern 'Economy' Oil is most probably far superior to the classic oils that seem to sell on nostalgia. Tesco Full synthetic runs a treat in the MKIII - the magnetic plug collects less debris than it used to now I'm using full synthetic, it warms up quicker, runs cooler - place your hand on the oil tank to find out. Tesco oil is most probably Comma/Mobil oil from Kent, has a better rating than Mobil 1 and costs far less than Classic gloop which means it is a win win situation as you still change the oil as you would with the expensive Classic gloop.

As far as I'm aware no oil company in the world sells an automotive oil that is tested and rated beyond 100'C, as air cooled machines running at temperatures like ours are a very very small portion of the industry. They justrecommendthat it is changed more often to overcome the fact it will break down quicker.

All oils which meet API or ACEA specifications are tested at 150 deg. C. and max. power for 72 hours, allbeit in different engines and with different fuels. Then piston deposits and ring stick are rated and viscosity increase at 40C. measured. Limits for passing are set at a pretty strict level. Since most good oils have both API and ACEA approvals., they have been double tested at high temperature.

Thanks Charles I stand corrected, it seems that oil testing has moved on and the bar gets ever higher. I notice the 150 deg.C. test is a conical cone test with obviously heated oil. I notice some of the latest tests require evaporation tests to be done at 250 deg.C. I suppose full oil testing done at temperatures above 100 deg.C. would be cost prohibitive and have to be done inspeciallymade 'aircooled' engines which would be to expensive to make and not representative of the market in which the oil is used.

Just confirms mybeliefin using the latest technology in oil design as it makes sense to use an oil which far surpasses the 'Classic' oil standard of the time but costs less.