Can I use synthetic motor oil in older motorcycle engines?

Most modern motorcycles recommend synthetics, but many people wonder whether they can use synthetic motor oil in older motorcycle engines. It’s obvious that there are many reasons to use synthetic motor oil which holds many advantages over regular crude derived lubricants when used in high performance motorcycle engines, but one has to exercise caution when deciding to use synthetic motor oil in older motorcycle engines.

The use of synthetic motor oil in older motorcycle engines can lead to problems.

In order to understand why you might not be able to use synthetic motor oil in older motorcycle engines we need to understand a minor but fundamental change to the composition of modern engine lubricants – whether they’re synthetic or mineral based lubricants. Since the 1970’s the world has began focusing on global CO2 emissions, with OEM’s taking severe measures to reduce the amount of pollutants the modern motor vehicle pumps into the atmosphere. In so doing one of the more effective countermeasures has been the catalytic convertor that scrubs the exhaust gasses of many of the harmful pollutants.

The precious metals used as a catalyst in these systems are susceptible to poisoning by lead and zinc, amongst other metals. In order to ensure longevity of the expensive catalytic convertor, oil manufacturers have ceased to add zinc to their motor oil (Or drastically reduced this zinc as an additive). Zinc performs very well as a lubricant under very high pressures, such as those found in the valve gear of high performance motorcycle engines.

The removal of zinc from modern engine lubricants therefore can have an adverse effect on engine life if you use synthetic motor oil in older motorcycle engines.

When can you use synthetic motor oil in older motorcycle engines?

It’s important that you understand that it’s not the synthetic motor oil in older motorcycle engines that’s a problem (Although some older seal materials tend to swell when coming into contact with synthetic polyalphaolefin motor oil) – ALL modern mass blended motor oils have less or no zinc added.

However there are several oil companies that produce specially blended synthetic motor oil for older motorcycle engines that contain small amounts of zinc specifically so that you can use synthetic motor oil in older motorcycle engines. Obviously it’s important that the motorcycle is not equipped with a catalytic convertor in this instance.
Having looked at the reasons it might be risky to use synthetic motor oil in older motorcycle engines some of the classic motorcycles are relatively load free and may not experience any problems if switched to synthetic engine lubricant. This however, can be risky, as the only tell-tale signs that you can’t use synthetic motor oil in older motorcycle engines will be excessive wear of the valve gear.

Before taking the decision to switch to synthetic motor oil in older motorcycle engines it’s important that you get advice from a professional supplier of quality synthetic motor oils, such as Habot Oil, who produce high quality synthetic lubricants for a wide range of applications.