May 18, 2010

Your Opinion, My Opinion

All Rights Reserved © 2009 Thomas W. Day

On a web mail list, I stumbled into a discussion about air filters and it quickly turned into a pissing match between a guy who hated everything about the brand of filter that I've used for almost 30 years and he was pretty unimpressed with all other filtration options. I was a little put off by the dude's venom, so I bailed out of the discussion and fired up my word-processing software to write this column.

In my life, I have been rightly described as someone who is overly-dependent on personal experience and practical application. I'm all for science and theory, as long as it doesn't get between me and getting something done, but I'm not dependent on the advise of sanctioned experts or popular opinion. I've personally known quite a few of the folks the media uses for expert opinions and I'm not particularly impressed. They are all good men and women, but just like you and me they have opinions and their opinions are no more founded in fact than yours or mine. Sometimes, less so. In the end, if something I've been doing has worked for me, I'll keep doing it even when the experts claim it doesn't work. I'd rather spend my time fixing the things that are broke and the things that aren't will get my attention in my next life; the life where I will be born rich and with lots of idle time on my hands.

Sometimes, even well-intentioned scientifically conducted studies don't impress me. Of course, some scientific studies don't live up to the name, either. (I wasted a decade in medical device manufacturing and saw more of that kind of science than I want to think about.) Often, the constraints of a study limit the value of the study to rare conditions. For example, if a rat has a forced daily diet of one-fourth of his body weight in a given substance, he will get fat. Therefore, said given substance is fattening. Yeah, I'll keep that in mind the next time I sit down to a 50pound dinner.

In the case of the aforementioned air filter discussion, the one and only test I found on the subject assumed the user would improperly clean and prepare the filter and, therefore, the filter would be ineffective. On the other hand, I have subjected my bikes to above average dirt road and trail exposure and have seen no signs that my applications of this same filter are allowing above factory filter contamination into the engine. In fact, I have seen signs of contamination on the intakes of other bikes using stock or aftermarket paper filters that I never seen in my bikes. I was told that a poorly functioning filter won't necessarily leave signs on the intake manifold. 2-strokes, especially, tend to produce dust accumulation on the manifold, since the fuel-oil mixture provides a little glue for the contamination. Obviously, engine wear would increase with poor filtration, too. I see those signs of air filter failure on others' bikes when I maintain them, I don't see it on mine, for what it's worth.

I do not know what it's worth. I only know that I'm likely to change my behavior when I see evidence that what I'm doing doesn't work. The older I get, the less inclined I am to experiment with things that seem to work for me.

On the practical side, when I go on a long, backroads trip I don't worry about being able to find a clean filter after a couple thousand miles of dirt roads. All I need is a little soap, warm water, and a small can of filter oil. I don't need a Suzuki dealer, of which there seems to be a short supply in Canada or Alaska or North Dakota, for example.

In the mid-70s, when I first started using this brand of filter, a cross country race in western Nebraska provided a pretty severe test. About twenty miles into 120, the racers got hammered with a dust storm so thick that it was hard to see twenty feet ahead. In the dusty valleys, visibility dropped to less than ten feet. It was a Dust Bowl quality storm, a huge black cloud of sand and dirt that rose out of the southwest horizon and swept over the land like some kind of Hollywood supernatural evil. On top of the dust, the terrain was difficult and dry and the race would have been dusty, even without the storm. With the storm, bikes fell to the side of the road --sputtering and dying--like diseased animals in a plague. When I finished the first lap, I stopped to replace my choked up goggles and my wife and daughters got a kick out of my racoon-eye'd appearance. My mouth and nose were full of dirt, and I spit out the first half-gallon of water I tried to drink as it turned to mud in my mouth.

I took of for the second lap as the storm really turned ugly. About halfway through that lap, the event organizers threw in the red flag and called the event. Out of the original 50-or-so bikes, there were about a dozen of us still running. We cut across the course in a blizzard of dirt and fumbled out way back to our cars and trailers.

Some racers headed for Ogallala, where they planned to hide out in a bar or motel until the storm passed. I had to be back at work on Monday, so I pointed my car east and hit the freeway trying to out run the storm. A few miles later, my car's hydraulic clutch died. Both the master cylinder and the slave were seriously leaking fluid. Without a clutch and towing a trailer, getting back on the road was a hassle, but I had enough fuel to get home and planned to run every stop sign and light that didn't cooperate with my objective. Fifty miles later, my brakes became suspiciously soggy, but they still worked and I escaped the storm and made it home without any additional problems.

After repairing the clutch and brakes on the car and hauling a bucket of sand and dust out of the interior, I started getting the bike ready for the following Sunday. When I pulled the top off of the bike's filter box, I was amazed to see how much dust surrounded the filter. It was nearly buried. To keep from pouring crud into the cylinder, I pulled the whole air box off and dumped it out before removing the air cleaner for service. Still, not a speck of dust to be found in the intake manifold. I raced the bike for another year, sold it to a friend, and it lasted one more year off road before it died. The little Rickman ended up in the old motorcycles graveyard because the new owner tossed the air filter when it became so packed with river sand that the bike stalled. He almost made it back home before the motor seized. I don't know what that proves.

I've been using the same brand of air filters for exactly the opposite reason on my cars (older cars, anyway) and dirt bikes since the 1970s and I'm always amazed at how clean my intakes have been after some really nasty events and LD rides. Maybe it's the preparation and maintenance that bothers others? I put 380k miles on a 1973 Toyota HiLux pickup over 20 years and it was running strong when I sold it. Its whole life was spent with a the same filter. My CX500 gave me 130k miles with only a timing chain problem all with the same filter. All of my dirt bikes, from an OSSA Phantom to a Yamaha XT350 to my current 250 Super Sherpa breathe through that brand. So does my current bike, a Suzuki DL-650. I just have no motivation to change, so until some catastrophe inspires me to amend my opinion I'm sticking with what has worked for me.

I'm not trying to convince you to go with my brand. I'm not trying to convince you of anything except that the old adage "don't fix what ain't broke" isn't a bad way to go. It's not rocket science, but that's not all it's cut out to be either.


  1. The non-mentioned filter brand is finding a way into the air box on my DL650 V-Strom this week. Until now it has been OEM filters. My latest service had too much junk on the wrong side of the filter. I hope the clean, oil and re-install brand will perform better with my abuse.

  2. I think you'll do fine. Be careful to clean it well and apply the oil exactly as the manufacturer describes. A little care during routine maintenance goes a long, long ways.

  3. I have been using the K+N filters on my 2003 cb750 its whole life. I love it. Like T.W. wrote, "Be careful to clean it well and apply the oil exactly as the manufacturer describes." I have used this brand on all my bikes starting in the early 80's, and never had a problem. If I am correct you save money in the long run not buying a new filter every year.


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