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The Genius Of Black Gold : Motor Oil

Rich wants more love and understanding for that humble yet hardworking can of motor oil.

Time to change out the miracle juice. Most people don’t appreciate how hard oil works to keep us going down the road. A very thin layer of motor oil (less than one thousandth of an inch, in fact it can be as little as .00004 in the bearing load zone) keeps metal surfaces from contacting each other against powerful forces. It neutralizes or at least holds in suspension blow-by contamination (combustion gasses sneaking past the piston rings) and other miscellaneous gritty bits and microscopic wear particles on the path to the filter. It can absorb a little (not much) condensation moisture and hold it until the engine is warm enough for it to evaporate out the crankcase ventilation system. 

Motor oil helps cool the engine by carrying heat from the hottest areas. Whether you use synthetic or conventional mineral oil, it gets dirty and eventually needs changing. The truth is, oil never wears out, but it gets dirty and loses the all-important additive package that makes modern oils so good at their tasks. The used oil you leave at the recycle centre can be re-refined and it’s back good as new. (How’s that for being green!) 

In industry, oil is sampled and its longevity determined by analysis—it’s big industry. Some commercial truck engines boast of one million mile oil changes, using super filtering systems and periodically adding additive packages.  Some newer cars have computer programs that monitor not just mileage but other parameters as well. For bikes it seems there are as many philosophies as there are riders. 

My personal modus operandi was handed down from my dad; I have been using it for decades and have never had an motor oil related failure. He said, “Change the oil before the manual’s mileage numbers and change the filter every second time.” 

Before you sit down to send some hate mail think about it. If the oil is changed before it gets real dirty and the viscosity starts changing, chances are the filter is still in pretty good shape. I think sometime folks are a little too uptight about filters; it’s just a filter, as long as it’s decent quality it’s likely good enough, far beyond the old days when a bit of coarse wire mesh was all you got for protection. The oil now is so good it almost takes care of itself. Of course if there has been a catastrophic failure not only do you need a new filter, but also a complete engine flush.  

Here is a tip for Dyna owners: the filter is not always easy to get off, most common filter wrenches don’t work great and there is always a mess. Since you don’t reuse a filter I have no problem destroying it. My preferred removal tool is a cheap Philips head screwdriver, hammer it in and turn. The added benefit is the hole: turn it to the bottom and let the oil drain into your makeshift spillway. A half turn usually does not cause the O-ring end to leak—at least not much. 

By the way, I have used automotive filters on this bike since 1996 with no issues. Any filter made for a 1990s three-litre Ford Ranger works. This time I am splurging ($15) on a Fram Ultra Synthetic XG 3600. It cost twice what I normally pay but is still about $10 cheaper than a motorcycle specific filter. This super filter claims it can protect up to 24,000 kilometres, but I won’t push it that far.  I like the metallic bronze finish, which goes along with my root beer paint job.

Which kind of motor oil to use is another debate with no end in sight. I have written about this before and came to the conclusion that I could not tell the difference between the premium synthetics. All are great and reduce friction over conventional oils. But they cost more; if you are not racing or riding an air-cooled bike across the desert they are not absolutely necessary. Racers want the best. 

My buddy Earl pays about $100 for a four-litre jug of Motule, and says it makes a difference in his son Nathan’s RMZ. It’s about twice the cost of most other premium brands, but knowing Earl if he is paying that much it works! Some people save money and swear by Shell’s diesel inspired Rotila T. It’s motorcycle rated and costs about half that of other premium synthetic brands prices. I am going to try it soon.

For now, I’m using Castrol Power RS Racing 4T 10W-50 (about $16 for a US quart). The Harley is good to go for another four or five thousand kilometres. Time to ride.

By Rich Burgess Canadian Biker Issue #324


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