As you can see, most myths appear to have some basis in reality, and that's what makes them dangerous. They're also a way to explain the unexplainable without doing a whole lot of research. Since our ancestors had no way of knowing what actually caused thunder, they accepted that it was formed by Thor riding through the heavens in a cart pulled by fire-snorting goats.
The problem is that accepting a myth at face value often has unpleasant repercussions. In the past, it sometimes meant sacrificing a virgin or two to appease the gods, while in modern times, it may mean spending the rest of your life hooked to a feeding tube 'cause you bought into a really dumb myth like "helmets kill more riders than they save." Which, I suppose, is a form of human sacrifice after all, isn't it?
The Old High-Low Game
Q I ride a 2005 Nomad, the successor to my 2003 Mean Streak, on which I spent 34,000 extremely pleasant miles. Kawasaki recommends for both bikes a fuel octane rating in excess of 90. A friend who rides a 2005 Gold Wing was told by his Honda dealer that he could run the low-octane (and lower-priced) gasoline found at our local establishments without any problems. My dealer said much the same: Use the 87-octane, and if it pings a little, bump up to the next grade. Both dealers said it wasn't necessary to run the high-octane stuff. If the lower-octane fuel won't harm the engines, why do the manufacturers recommend the high-octane stuff?Larry E. WhitesideDurango, COVia e-mail
A Excellent question, Larry. Because the OEMs don't know how hard a given bike will be ridden, they like to err on the side of safety when it comes to anything that could cause damage and increase warranty claims. Hence, they'll often recommend a higher octane than may be strictly necessary, just in case detonation does become an issue. In this case I agree with your dealer: Run the lowest octane you can find that doesn't detonate. In addition to saving a few shekels at the pump, you may be pleasantly surprised to find your bike starts better, idles smoother and may even make a bit more power on regular than it does on high test. (See this month's Tech Matters column to see why.)
How long?
Q I enjoy reading your column in Motorcycle Cruiser; I always learn something new. I was wondering about the longevity of some motorcycle engines. About how long does the Harley-Davidson Twin Cam engine last before needing a rebuild? When a rebuild is required, what normally needs to be fixed to get it back in good condition? In comparison, how long would a liquid-cooled, four-cylinder Japanese engine like the one in the Yamaha FJR1300 last? What would need to be repaired should a rebuild be required? Thanks for your time and input.AndrewVia e-mail
A Any engine's life expectancy is based on the way it's broken in, used and maintained. Assuming both engines are kept dead stock, properly broken in and maintained in accordance with the factory schedule, I'd expect either one to last damn near for-ever. Obviously things do go wrong, so there's always the possibility that something unusual will surface, but in general, either engine should last hundreds of thousands of miles.
If either engine did require a rebuild, I'd expect to replace the same parts in both-pistons, rings, main bearings, valves and guides, etc. After all, both engines are four-strokes, so they use the same parts (although obviously the Yamaha has more of them). The Yamaha is somewhat of a ringer, though, because its transmission shares its oil supply with the engine. That being the case, it's possible that contaminated engine oil, say, from a worn-out bearing, could damage some of the transmission components. That scenario can't occur on the HD because its transmission is housed in its own case, with a dedicated oil supply.