READERS often ask if they should use top of the range engine oils in their motorcycles. Well, if you can afford to pay $32 for a litre of fully synthetic 4-stroke engine oil, go for it.
This means you will be paying more than $100 every time you service a motorcycle with a 2.8-litre oil capacity, on top of the oil filter change.
Such premium oils claim to better protect a motorcycle engine because under extreme pressure and heat, these oils, which contain ester, lubricate moving engine parts and do not degrade easily.
But can a rider use a less expensive synthetic oil, like the Repsol Moto 4T racing oil and still enjoy a worry-free riding experience?
The answer requires understanding of what you're paying for, how you treat your motorcycle and what your motorcycle engine requires.
Expensive
The top of the range oils are the Grade V ones containing esters, while Grade I oils are generally mineral oils. Through an expensive chemical process, fatty acids are converted to esters which have a magnetic quality, allowing them to stick to engine parts.
This is good news, particularly if you're the type who abuses a motorbike by riding hard or neglects maintenance schedules.
Sitting below this category are Grade IV oils, also known as PAOs (polyalphaolefins), which the Repsol Moto 4T belongs to.
The process of manufacturing the wax-free Repsol is cheaper, hence its $22-a-litre price tag.
We were curious if there would be any difference when we starved a 10-month-old 600cc sportsbike of its ester-based diet of engine oil by using the Repsol instead.
This is no scientific experiment, but one based on observation.
The Repsol oil is slightly thicker with a viscosity of 10W50, as compared to the previous 10W40 synthetic oil we had used.
The Spanish-based company claims the oil has been developed through racing and is meant for motorsports.
We switched to the Repsol at the 8,000km mark on the odometer.
The bulk of my riding is street with 20 per cent of the time dedicated to track riding.
After riding for 3,000km, we drained the oil and gave it another 2.8 litre dose of the Repsol.
So what did we find?
The engine cranks enthusiastically during morning start-up.There was no change in operating temperature.
Cruising at 90km, the temperature registered on the digital dashboard was the same at 78 deg C.
Cracking the throttle open at a circuit saw a 2 deg C drop, similar to previous engine oil.
Clutchless gear shifts on the circuit were smooth. We did not notice any clutch slippage, too.
A small difference was inherent only when starting off.
The more expensive oil made a louder 'clank' whenever the gear was shifted from neutral into first.
Two mechanics explain that this was probably due to the thinner and slicker properties of the more expensive oil.
Dismantling the top portion of the engine revealed that there were no 'hot spots' or unusual carbon build-up on the pistons when using the Repsol.
Perhaps the 3,000km oil change interval was too short an interval.
While the motorcycle manual suggests a longer interval, I stick to this practice for insurance.
Another part of my 'insurance' is knowing that one local race team has been using the same oil in races across the border.
So far, none of their engines have blown during competition.
Racers often face a dilemma - in order to gain horsepower, they choose a thinner oil, so that moving parts will have less resistance to the oil in the engine.
But sometimes, the extreme heat build-up could destroy the oil, rendering no protection to engine parts. Before long, the engine could blow, the same two mechanics we spoke to said.
In my opinion, the Repsol still does its job of cooling the engine, keeping impurities at bay and keeping engine operation slick.
Best of all, I get change every time I flash $100 to my mechanic during oil changes.
