Loud Pipes, Synthetic Oil, And More - Hit,Or Myth? - Tech And Accessories

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Myth: 1. A traditional legend or story, especially one that explains a cultural practice or natural phenomenon 2. A fictitious story 3. An unproven or false belief (Random House/Webster's Dictionary, 4th Edition)

To my way of thinking, myths are among our worst enemies. At best, buying into them can make you look foolish and, at worst, get you seriously hurt or dead. Accordingly, I like to do a little periodic "myth busting" just to keep everyone on their toes. If you accept any of the following as gospel, feel free to make your case, but be forewarned: Your words may come back to haunt you in a future issue.

1 "Loud pipes save lives." I'm not going to say this is the silliest thing I've ever heard, but it's up there. Supporters of this myth tend to use anecdotal evidence to prop it up, usually of the "a truck was about to cut me off when he heard my pipes and veered back into his own lane" type. You can argue this one all you want, but I don't buy it. Maybe your loud pipes startled some poor schlep as you blasted past, causing him to swerve, but if he heard you, why was he about to cut you off in the first place?

Since I've never seen any empirical evidence to support the loud-pipes theory, I'll go on record as saying if anyone can make a case based on scientific results, I'll be happy to run it in the next issue with a full apology.

2 "You can't use synthetic oil in a motorcycle engine; it'll make the bearings skid and wipe out the motor." The theory here is that synthetic oil is so slippery that it prevents the rolling elements of ball and roller bearings from turning. It's an interesting idea, but like most myths, it's just a lot of smoke. The fact is that synthetic oil is no more "slippery" than any other oil, and using it in a roller-bearing engine won't cause the least bit of harm.

3 "Don't use the front brake-it'll toss you over the handlebars." This is the oldest one on the books, and I seriously doubt anyone still believes it, but I had to include it for old time's sake. My guess is this tale got started back in the days of dirt roads, when a good squeeze on the front brake lever could lock the front wheel and cause a slide. Why it persisted as long as it did says a lot about people's willingness to believe a good story despite evidence to the contrary.

4 "Always burn high-octane gas-your bike will make more power." This one certainly sounds plausible, but here's why it isn't: From an energy-producing standpoint, there's not much difference between high- and low-octane gas. However, high-octane fuel is formulated to resist detonation, and as such it's less volatile, meaning it's harder to ignite and burns slower than low-octane fuel. When an engine is designed to run on regular, the anti-detonation characteristics of high-test gas can work against it to cause hard starting, poor idling and, in some cases, reduced power. The truth is that burning high-test gas in an engine that doesn't require it is a waste of money and may actually reduce power.

5 "Never use anti-seize (or grease) on a nut or bolt-it'll make the threads slick, and they'll come loose." Like most myths, this one illustrates a fundamental misunderstanding of certain realities.

Think of a bolt as a spring; when it's tightened, it stretches slightly and applies a predetermined clamping force to whatever you're trying to hold together. To do its job properly, the bolt must be properly torqued to a predetermined value. When hardware is assembled dry, some torque is used up overcoming friction between the threads. This generally leads to an undertorqued-read that as loose-bolt. Lubricating a fastener will reduce friction as the bolt is tightened and provide the proper torque setting. So unless the manufacturer states otherwise (and there are instances where they will), always lightly oil a threaded fastener before installing it.

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.

Ok, So Maybe Not That Worried...Q I I have a brand-new 2006 Honda VT750cc Shadow Aero. It's a 745cc SOHC, three-valves-per-cylinder V-twin. The service manual says to check valve clearance at 600 miles, 0.006-inch intake, 0.008-inch exhaust, two intake valves, one exhaust (stated right on the frame under the seat!). After reading your article on valve adjustment on the Motorcycle Cruiser Web site, I thought I'd give it a try, especially when the dealer told me the adjustment wasn't included in the $60 first service. He also said a valve adjustment would be $250! I can believe it, because to get valve covers off you have to remove the seat, tank, air hoses, etc. My problem is that I'm not sure what the clearance is with the feeler gauges-it wasn't as straightforward as I thought. I think the valve lash is a little tight (maybe 0.004 inch plus or minus), and I'm a little worried, but not $250 worth of worried. Is it common for new bikes to have tight clearances? Particularly Hondas?Dave HunterVia e-mail

A Yeah, Dave, it is normal for a new bike's valves to tighten up a bit. As the new engine is run, the valves tend to pound into their seats; this causes a slight loss of clearance and is entirely normal. For the novice, valve adjustment can be a little tricky, mainly because it does take some experience in using a feeler gauge to develop just the right "feel." Until you develop that feel, I'd suggest using what's called a Go NoGo feeler gauge, available at any tool supplier or auto-parts store, to set the valves. Go NoGo gauges are stepped or graduated. When the adjustment is correct, the first portion of the gauge will slide freely, yet the second portion won't. For example, on your intake valve you'd use a Go NoGo gauge that had a leaf stepped from 0.006 to 0.008. When the adjustment was correct, the 0.006 portion of the gauge would slide freely, while the second portion, the 0.008, would stick. As an alternative you could also double-check the valve using two separate gauges, an 0.006 and, say, an 0.007 or 0.008. If the 0.006 slips in, and the 0.007 or 0.008 doesn't, you're good to go.

strong>The Four-Stroke Internal Combustion Engine - How-To** Fundamentally, there's not a whole lot of differences between a one-lung lawn mower engine and MotoGP World Champion Nicky Hayden's hand-built V-5 Honda. Both engines employ the same basic architecture and operate according to the same easy-to-understand physical laws. The only real difference is in the details, so once you grasp the basics, the rest is easy. Here's the lowdown on how a four-stroke internal combustion engine works.

One Piece At A Time
Mechanical devices are easier to understand when they're reduced to their components. Hell, even the space shuttle starts as a single bolt, so let's begin by taking a look at a typical four-stroke engine's major components

The crankcase houses the crankshaft and, in a traditional pushrod engine, the camshaft. It also accommodates secondary mechanisms like the oil pump (and water pump if needed), the alternator rotor and stator and sometimes the ignition system. In most instances, the clutch, primary drive and transmission also reside in the crankcase, with the major exceptions being Harley-Davidson FLs, BMWs and Moto Guzzis, all of which have their transmissions bolted to the engine, automotive style.

The purpose of the crankshaft is to change the reciprocating motion of the piston into rotary motion and to feed energy into the clutch and transmission. Think of a bicycle pedal crank and you'll have a pretty good idea of how one works.

There are two types of crankshafts, the assembly, or "built up," type, which is made up of right- and left-hand crankshaft halves assembled onto a crank journal or pin, and the unit, or one-piece, crankshaft, which is forged or machined out of a single chunk of iron or steel. As a rule, built-up cranks use roller bearings and one-piece rods, while unit cranks use plain bearings and two-piece, or "split," rods. Harley-Davidson FL and XL motors use built cranks (as they have since their inception), while more, uh, current designs tend to go with unit cranks.

Because you've got a lot of parts thrashing around at high speeds, the crank assembly needs to be accurately balanced-if it isn't, it'll shake itself and the rest of the motorcycle, including the rider, to pieces in short order. Modern engines incorporate a balance shaft to counteract the crankshaft forces and reduce vibration.

Connecting Rod
The connecting rod connects the piston to the crankshaft. Because the rod swivels in relation to the piston and the crankshaft, it's fitted with a bearing at either end. The small-diameter end of the rod connects to the piston and normally has a plain bushing, while the larger-diameter end is mounted to the crankshaft and utilizes either a roller bearing (H-D X and F motors) or a plain-insert-type bearing (everyone else)

Rod materials include aluminum, steel billet and, in some high-performance applications, titanium. In most cases, the rods are either forged or machined from stock, although the latest technology uses a procedure called "powder metallurgy, " which is a sintering process that uses high pressures and temperatures to create extremely strong, light and expensive rods out of metal powder.

Roller bearing rods are built in one piece and installed during the crankshaft assembly process, while split rods have removable end-caps that allow them to be installed over the crankshaft. When sintered rods are used, the end-cap is separated from the rod body by fracturing, which results in an uneven mating surface. When the rod is installed, the slightly jagged ends ensure a perfect cap-to-rod alignment, compared to the minor misalignments that can occur if the mating surfaces are both flat. As I recall, the late BMW CL models used fractured rods, but I can't think of any cruisers currently using them.

Piston, Rings And Wrist PinThe piston is used to compress the mixture in the cylinder and to transfer the energy of the expanding gases to the crankshaft. Since they're subject to extremes in heat, pressure and acceleration, pistons need to be extremely durable and constructed to very high standards. Consider a Honda VTX1800 that's turning 3,000 rpm. At those speeds, its pistons travel 34 feet per second, with a piston crown temperature that averages 600 degrees Fahrenheit.

Most pistons are either cast or forged out of aluminum alloy, although some high-performance versions are machined out of aluminum billet. For years, cast pistons were at the bottom of the performance food chain, but the introduction of the "Hypereutectic" cast piston (look it up on Wikipedia) has changed that perception. Currently, most production motor-cycles use some form of Hypereutectic piston, and they hold up extremely well.

The piston is fastened to the connecting rod by the wrist pin, which in turn is held in place by spring steel clips or, sometimes in high-performance applications, by aluminum or Teflon buttonsz

The cylinder's function is rather obvious: It acts as a guide for the piston and contains the expanding combustion gases. What's less obvious is how it's put together. Unless they're for a very special application, cylinders are made from one-piece aluminum castings that have either a steel sleeve called a liner pressed into it or utilize special hard-metal "chrome" plating.

Pressed-sleeve cylinders have been around since Hector was a pup and continue to work well. They're inexpensive to build and can be easily overbored or relined in the event of damage, or to facilitate the installation of big-bore kits. On the downside, they don't transfer heat as well as they might, but for most of us that's a minor concern.

Plated cylinders are lighter, cool a bit better and are more resistant to wear than the sleeve type. Unfortunately, they can't be repaired without very specialized equipment and are slightly more expensive to manufacture. For the most part, they're found only on bikes that place a premium on performance, such as hard-core sportbikes, pure race motorcycles and cutting-edge, performance-oriented cruisers like the Suzuki Boulevard M109R.

As a rule, most motorcycle engines use removable cylinders that are fastened to the crankcase with studs and bolts, just as they have been since the early 1900s. It works, but makes for a flexible crankcase assembly and a ready-made path for leaks. A better idea would be casting the cylinder "in-block"-meaning that the upper crankcase half and the cylinders are made in one piece. Casting in-block makes for a rigid, leak-free and more compact cylinder assembly and eases the installation of water-cooling passages and cam drives. Honda is a proponent of in-block construction, with the old CX 500/650 series, the Magnas and, of course, Gold Wing/Valkyries being the examples that come most readily to mind.

While there are many good reasons why manufacturers don't want to adapt this method (primarily cost and complication), I can't help but think that somewhere down the road we'll be seeing lots more of them

Piston rings are used to create a gas-tight seal between the cylinder and the piston to assist in keeping the piston cool (about one third of the piston's heat is transferred through the rings to the cylinder wall) and to control cylinder wall lubrication.

Common practice is to use two compression rings, locating them as close as possible to the top of the piston to seal the combustion chamber, and one oil control ring positioned just below them to prevent lubricating oil from migrating into the combustion chamber. The rings are split to ease assembly and to allow for thermal expansion. Like the piston, they take a real beating, so they're normally made of a hard yet elastic material like ductile cast iron or molybdenum steel alloy. To enhance longevity, rings are often plated with chromium, nitrided or, in some cases, wear a ceramic coating.

Modern rings are incredibly well made and durable. When I began riding, rings lasted anywhere from 10,000 to maybe 30,000 miles before they needed replacement, and many riders did the job on their own beneath the shade of the nearest tree. Nowadays, they'll last anywhere from 100K to 200K, and I'd bet the majority of you have never even held one in your hand. Progress is a wonderful thing.

Cylinder Head
Engines are a lot like people in that they breathe through their heads. At times they're also leaky, cantankerous and obstinate, which makes them a lot like me, but I digress.

Cylinder heads have three main components: the intake port, which allows fresh mixture to flow into the engine; the exhaust port, which is where it exits; and the combustion chamber, which is the recessed area machined into the head where ignition and combustion take place (although there's one design, called a Heron Head, that locates the combustion chamber in the piston crown). Because the head controls flow and combustion it's where the bulk of an engine's torque and horsepower are created, so engineers and tuners go to great lengths to get the design just right.

A camshaft is defined as "a rotating body with an eccentric protuberance, which, as it moves, imparts a linear or angular movement of cyclic nature to some other component of a machine." Huh? How about we just say the camshaft, or cam for short, is a shaft that has ramps on it that open and close the valves at the proper time as it rotates.

Cam location varies according to engine design. Pushrod engines, like the Yamaha XV1700 Road Star and Harley-Davidson FLs and XLs, locate their cams in the crankcase adjacent to the crankshaft and operate the valves through pushrods and rocker arms. Single-overhead-cam engines, like those used in the Victory Kingpin and Honda VTX1300, position their cams in the head, directly between the intake and exhaust valves. The hot rod Suzuki M109 uses a double-overhead-cam engine (that's four cams total, two per cylinder), with each cam being positioned directly over the valves it operates, as does the Yamaha V-Max. It's a complicated way to go, but the added performance makes it worth the trouble.

Because the valves are only open during two of the four strokes, the camshaft is always driven by the crankshaft at exactly half the engine's rpm, regardless of location, design or the number of cams.

Valve Train
The valve train transfers the cam's actions to the valves; its design varies according to cam location and normally encompasses several components.

In a pushrod engine, these include valve tappets, which run directly against the cam and pushrods, which transfer motion from the tappet to the rocker arms. And, of course, the rocker arms, which transfer motion from the pushrod to the valves. Single-overhead-cam mills also use rocker arms to operate the valves, while double-overhead-cam engines generally run their cams either directly against the valves, through an interposed shim or by using a short rocker arm.

Critics of the pushrod engine are quick to condemn the admittedly dated design, complaining that the system is complicated, heavy and flex-prone, all of which limits performance. While they have a point, I'd point out that NASCAR and the NHRA boys build some pretty powerful pushrod engines and that Yamaha and HD twins are no slouches, either.

The current trend is to fit any piece that bears directly on the camshaft (for instance, the tappets in a pushrod motor or the rocker arms in an OHC design) with a ball bearing to reduce friction. Since the end result is less wear and more performance, I'm all for it.

Making Noise
So now that we have some idea of what everything does on its own, let's see what happens when they act in concert.

Technically, what we're looking at is called the four-stroke-cycle engine, not because it's installed into a motorcycle but because it takes four strokes of the piston (two up, two down) to create one power-producing cycle. For the sake of brevity, we're going to assume that valve and ignition timing events begin and end at top dead center and bottom dead center; in real life, an engine set up that way wouldn't make much power, but it does simplify the explanation.

Intake Stroke
The intake stroke starts with the piston at the top of the cylinder, which is called top dead center position, or TDC for short. As the piston descends toward the bottom of the cylinder, the cam opens the intake valve. As the piston moves down, it creates a low-pressure area in the cylinder directly above it. Atmospheric pressure forces the mix of fresh air and fuel in through the open intake valve, filling the cylinder. When the piston reaches the bottom of the cylinder, or bottom dead center (BDC), the intake closes.

Compression Stroke
During the compression stroke, the piston moves from BDC back to TDC. Since both valves are completely closed, the mixture is compressed tightly into the combustion chamber. Why does it need to be compressed? First, compressing the gas thoroughly mixes all those fuel and air molecules and raises their temperatures, making them easier to ignite. Secondly, a compressed mixture expands with greater force when ignited than one that isn't.

Power Stroke
The third one's the charm. With the piston at TDC and both valves closed, the spark plug is fired, igniting the mixture. As the mixture burns, the gases expand, pushing the piston downward, rotating the crankshaft and feeding power into the motorcycle's drivetrain

Exhaust Stroke
The final step is to remove the burnt gases. As the piston reaches the bottom of the power stroke, the cam opens the exhaust valve. The piston now starts to move back toward the top of the cylinder and, as it does so, forces the spent gases ahead of it out the open exhaust valve. As the piston reaches TDC, the exhaust valve closes, and the cylinder is ready to start another intake cycle.

There you have it. Like too many things in life, engines appear mysterious to the uninitiated, when in fact they're pretty simple. Hopefully some of the mystery has now been replaced with understanding. If not, you've got my e-mail

Idiots Are Me...
When I make a mistake, it's a doozy, and there's a winner in the August Tech Tip "Recharge the Right Way." To reduce current flow, the load needs to be connected in parallel, not in series, as I stated. Sorry for the gaffe-I'll be studying remedial electrical theory over the summer.-MZ

Motorcycle Lifts 101Once found only in dealerships and available primarily through specialist suppliers at great expense, motorcycle table lifts have become both cheap and accessible, making them perfect accessories for do-it-yourselfers.

Before purchasing a lift, you'll need to consider a few basics. Obviously, space is one. Lifts average about seven feet in length, give or take a few inches, and you'll need at least a couple of feet in every direction just to swing your wrench. So make sure you've got the physical room before you place the order. Of course, you can always park the bike on the lift if space is tight.

Overhead clearance is another consideration, especially if your shop is in the basement. Typically, a lift will raise your bike somewhere around 30 inches, so add that to your bike's highest point when it's in the vertical position. I'd recommend at least two feet of clearance or you'll likely be picking parts out of the ceiling.

You'll also want to make certain the lift can support the weight of your bike. Although most table lifts are capable of handling a 1,000 pounds or so, some are rated at considerably less. It probably won't be an issue if you're tinkering around on a typical midsize cruiser but could present a problem if you're a Boss Hoss or Amazona enthusiast.

Power sources vary: Air- and electrically operated lifts are the most popular, with foot-operated hydraulics bringing up the rear. In-ground automotive-style lifts tend to be difficult to install and expensive, and as such, unsuited for home use. I prefer the electric lifts: They're less troublesome to use, don't need a compressor and use a screw-type lifting mechanism, which permits a fine height adjustment and also prevents the lift from dropping in the event you don't have the safety stands down during a mechanical failure. On the downside, they tend to be a bit more expensive and operate more slowly. My second choice would be the air-operated version. My last choice is reserved for the foot-pumped hydraulic style.

If you opt for the air- or hydraulic-type lift, make sure there's some sort of drop-down locking system just in case things go really wrong with the lifting mechanism.

Lifts normally include a drive-on ramp and a vise to lock the front wheel. If the vise is an option, I strongly recommend buying it. I've seen bikes fall off lifts, and it ain't pretty-or cheap. Other options include things like extendable sides, which are great if you're working on ATVs, snowmobiles or lawn tractors (and a way to sell the idea to the wife), and dropout panels that make removing the rear wheel a lot easier. Low-profile jacks are also helpful; with one end of the bike clamped to the lift, these jacks can raise and lower the free end incrementally, which makes tire changing or suspension work much easier.

As with any tool lift prices vary greatly; expect to pay anywhere from $1,000 to maybe $2,500 for one from the premium suppliers, such as Handy or Carlson. Their lifts are top of the line and won't let you down (no pun intended)-these are the ones I'd recommend if you're serious about working on your bike.

Cheaper lifts can be had too, and while I've had no practical experience with them, guys that have purchased them from places like Tractor Supply Co. (Clarke Tools) and the suppliers doing business on the 'Net tell me they're happy with them. Expect to shell out anywhere from $500-$1,000 for these, plus shipping.