Service

SERVICE

Paul Dean

Switching soundtracks

I have a 2001 Suzuki GSX-R750 that I really like, but lately I’ve been enjoying the sound of V-Twin engines more and more. I was just wondering if there were any way to make my inline-Four sound similar to a V-Twin-like maybe connecting two pistons straight to one muffler and the other two to a second muffler? Thanks in advance for your advice. George Garcia Brownsville, Texas

You’re plum out of luck, George. There is no way that any manner of exhaustsystem plumbing tricks can allow the sound of your inline-Four to emulate that of a V-Twin. Actually, some inlineFour exhausts do utilize the two-cylinders-per-muffler concept you suggest; and while this technique does have an effect on the exhaust note, the change is so small that only the most perceptive of ears can detect it.

Exhaust sound is one of the most intriguing, mysterious aspects of motorcycle design. The primary factor in determining the nature of any engine’s exhaust note is its cylinder configuration. A parallel-Twin with a 180-degree crankshaft sounds dramatically different than one with a 360-degree crank, and both of those have a different exhaust note than a V-Twin. An inlineFour sounds nothing like a Twin, and a Triple has a different sound yet.

Cylinder configuration has a significant effect on the way the sound waves emitted by each cylinder interact. Some waves complement each other, making those frequencies more prominent, while other waves partially or fully cancel one another. The end result is a distinctive sound that isn’t duplicated with any other cylinder arrangement.

What gives V-Twin engines their distinctive exhaust sound is the uneven phasing of their firing sequence, whereas an inline-Four has a perfectly even sequence. But even with V-Twins, the exhaust note changes according to the angle between the cylinders. A narrow Vee, such as a 45-degree Harley, has a particular tone, while a wider Vee, like a 90-degree Ducati, has a similar but different sound. If the cylinder spread is widened all the way to 180 degrees, as in a BMW opposed-Twin, the sound becomes completely different.

So, aside from installing a powerful sound system on your GSX-R and playing a recording of a V-Twin through it, you 're stuck with the high-pitched wail of the bike ’s inline-Four engine.

Vibration calibration

I work in a steel mill where we have equipment that checks vibration. Would it be possible to quantify vibration on a motorcycle by testing it at the handlebars, seat and footpegs throughout the engine’s entire rpm range? This would help consumers make a wiser decision when purchasing a motorcycle. Thomas indriolo Canton, Ohio

In theory, that’s a very intriguing idea, but in actuality, it would be extremely difficult for a magazine to incorporate into its road-testing regimen. The major manufacturers do, in fact, measure vibration when engineering new models or redesigning existing ones. While a new bike is still in the CAD (Computer Aided Design) stage, the engineers do this with sophisticated programs that predict the frequency and amplitude of likely vibrations at key points all around the motor cycle. Then, once a running model exists, they use other equipment to measure the actual vibrations.

The problem, though, is not just in quantifying the nature of vibration but also in determining which frequencies are tolerable by humans and which are not. There are some frequencies that everybody loves and others that everybody hates, but there ’s also a lot of frequencies whose impact is not so cut-and-dried. Depending upon many physical factors, including size, weight, bone structure and body density, some riders find certain frequencies bothersome or even debilitating while other riders do not.

When designing the C5 Corvette in the 1990s, General Motors conducted extensive research in this field. Those studies found that the previous generation of 'Vettes had natural resonant frequencies that went unnoticed by most men but tended to have an unpleasant effect on large numbers of women. Further research then attributed this phenomenon to the simple fact that most female bodies fall within a significantly different range of resonant frequencies than those of most men. As a result, the engineers spent huge amounts of development time and money “tuning” the C5 chassis to avoid the frequency ranges that annoy females while still allowing most males to receive the kind of sensory input they> prefer.

So, while we might be able to quantify a bike's vibration as part of our testing procedure, we could justify neither the cost of the required equipment nor the the time and personnel needed to operate it; and even if we could, our findings still would not be a guarantee of riding pleasure for all riders.

Besides, we already have ingenious devices that evaluate a motorcycle’s vibrations: We call ’em test riders.

Jet lag

My 1996 Kawasaki ZX-9R stutters from idle up to 4000 rpm. I went through the carbs and cleaned them-twice-but the problem didn’t go away. The bike was all stock when I got it and didn’t look abused at all, and it now has 5000 miles on it. 1 installed new plugs, a K&N filter and jet kit, and a full Muzzy exhaust. Any ideas would help. And thanks for the good magazine; it helps to keep our spirits up here in Iraq. Sgt. Mike Kuchinski Blaine, Minnesota via Bahquba, Iraq

Even though you have installed a jet kit, your ZX-9R has carburetion issues, most likely in one of the low-speed circuits. The K&N kit for your bike includes a selection of three main-jet sizes (HI 70, 180 and 190), along with new needles and needlespacing washers, replacement air-correction jets, different slide springs and two drill bits. The instructions show you how to use one of the drill bits to put a small air-bleed hole in each throttle slide, and how to use the other bit to gain access to the idle-mixture adjusting screws.

I’ve encountered similar carburetion problems that resulted from someone either failing to follow a jet kit’s instructions or installing only the main jets. If

you omitted any of the prescribed steps or did not change all of the components as directed, that would explain the stumbling off idle you describe.

Either that or you used the wrong jet kit. K&N no longer sells jet kits, but when it did, they were supplied by Dynojet. The correct Dvnojet kit for your ZX9R (with K&N filter and Muzzy exhaust) is No. 2155.01. I suggest you log onto www.dynojet.com, look up that part number and compare it to the K&N kit you used. If the contents are different, you may have installed the wrong kit.

A hell of a coil

1 hate asking stupid questions, but here goes one anyway: What is a helicoil? I’ve heard people talk about them, and I’ve seen them mentioned a few times in magazine articles, but I’ve never read or heard a description of what they actually are. I’d ask one of my more-knowledgeable riding buddies, but like I said, I hate asking dumb questions. Would you mind giving me an explanation? Kyle Eisenmann Posted on www.cycleworld.com

Not at all. But remember: No question is stupid if you don't know the answer.

A helicoil is a set of replacement threads used to repair holes whose original threads have been damaged so badly that they will no longer securely anchor their intended bolts or studs. It consists of a piece of very hard, tightly coiled wire that has a diamond-shaped crosssection; the wire shape is especially designed so the outside diameter of the wire functions just like the threads on a bolt, and the inside diameter functions like the threads in a nut or a hole.

To install a helicoil, you drill out the damaged hole to a larger diameter, use a thread tap to cut new threads in the enlarged hole, then screw the helicoil down into the new threads. Voila! A brand-new set of threads. Each helicoil set comes with instruction that explain the procedure for installation, including how far to drill out the damaged hole and which thread tap to use for cutting new threads.

Another type of damaged-hole repair is the threaded insert, which is a solid steel sleeve that has threads cut on the inside and outside. Its installation is very much like that for a helicoil, in that you drill the damaged hole out to a predetermined larger diameter, tap it, then screw the insert down into the hole.

Free power for sale

I have a question for the Cycle World techheads: Has anyone heard of a product called “I-CAT”? It’s one of those things you place between the coil and sparkplug and get “free horsepower and added torque” for only $200. They said it’s from England. Robert Broderick Sterling, Massachusetts

Call me crazy, call me cynical, but I don t exactly consider $200 "free.” If you have information that contravenes this theory, however, please enlighten me.

A device such as what you have described could do only one thing: increase the voltage of the spark that jumps across the plug gap. And while having a little extra zap might prove somewhat useful on a highly modified engine or an ignition with a notoriously weak spark, it would likely do zilch on any of today’s bikes. Besides, if the simple act of slipping an I-CAT onto the plug wires would boost horsepower and torque, don 't you think the factories would already have installed them on their no-expense-spared race bikes ?

Look at it this way: We ’re talking about an electrical component that comes from England, the country; that gave us Lucas electrics. I rest my case.

When Trumpets die

I own a 2002 Triumph Sprint RS that recently has started to give me a hard time. It stalls when I try to take off, and even after 10 minutes of riding on the freeway, it will stall at a stop sign. No engine-warning lights ever come on, and the stalling happens only when the weather is below 44 degrees F. I use Castrol 10w40 petroleum-based oil, but I am inclined to change to a different grade of oil. Otherwise, the bike is a blast to ride. Eduardo Garza Vista, California

Troubleshooting fuel-injection problems without having access to the affected injection system makes me feel like a blind man using a telescope on a cloudy night: I know there are billions of stars out there, but I can’t tell you if any of them are visible. Based on the symptoms you describe, though, it ’s my best blind-man ’s guess that one of the injection system ’s sensors is feeding the ECU (engine control unit) incorrect data. It could be the temperature sensor or the MAP (Manifold Absolute Pressure) sensor; either way, the net effect is that the ECU thinks the incoming air is either heavier or more dense than it actually is, so it feeds the engine a mixture that is too rich. You don’t notice this above idling speeds because the mixture ratio is not critical to allowing the engine to continue running; that ratio is critical at idle, though, so the engine stalls. Take the bike to your Triumph dealer and have them run a diagnostic check on the ECU. If I am correct, they should detect a faulty sensor.

Myles and miles

My son Myles just finished his first semester of engineering at Virginia Tech, so while he was home on break, I asked him to develop a formula for figuring the speedo error on my 1990 Kawasaki ZX10. Based on the fact that at 60 mph, a vehicle travels one mile in 60 seconds, he came up with a simple formula that seems a lot less complicated than others I have seen. You need a stopwatch, a milemarked highway and some patience for repeatability. The formula is: miles seconds x 3600 = speed. Here’s a quick chart based on the number of seconds required to travel one mile.

So, for example, 1 mile -p 55 seconds = .0181818 x 3600 = 65.45454 mph. Pretty cool, huh? Ed Killar Earlton, New York

Yes it is, but any method that involves using roadside mile markers calls for a few prerequisites. To achieve reasonable accuracy, you should time your speed over more than just one mile; I suggest at least two or three. If that isn't possible or practical, conduct a one-mile test at least three times and average the results. Plus, this technique is valid only if you are able to hold a steady speed over the entire measured distance-one mile, three miles, whatever. If your speed varies at all, the calculation will be off accordingly.

Stiff shifter

I purchased a used 1995 Honda XR250R last year, and with one exception, it runs wonderfully. Here in Michigan, we have thousands of miles of ORV trails, and on most of them, I’m almost always in first, second or third gear. After about an hour into the ride, the transmission becomes difficult to shift into fourth, fifth or sixth. It can be done, but I have to use my hand! At the start of the ride, the bike will shift through all the gears with little difficulty. When I explained the symptoms to the service manager at the local dealership, he told me that such a problem would require a $1500 rebuild. $1500? I could buy another 250 for that! Just in case you’re wondering, yes, I have changed the oil, using what Honda recommends. Can you help? Wayne Riddle Grand Rapids, Michigan

Recall Roster

NHTSA Campaign ID No. 04V05200 Recall date: Jan. 22, 2004 H-D Dyna Glide Series Model year: 2004 Number of units involved: 4593 Problem: On certain fuel-injected models, the rubber fuel hose has the potential to separate from its inner liner, causing a fuel leak. This could result in a fire. Remedy: Dealers will replace the fuelline assembly. Owners who do not receive the free remedy within a reasonable time should contact HarleyDavidson at 414/342-4680.

My best advice is to find another dealer. According to Honda’s fiat-rate schedule, it should only take about 6 hours to remove, disassemble, reassemble and reinstall an XR250 engine. That doesn '( include the time needed to fiddle with the gearbox, but at a rate of $65 or $70 an hour, the total labor charges still should not go much over $500. So, the dealer is either charging $250 an hour for labor or thinks the repair will call for $1000 in parts-both of which are absurd.

I can't give you an exact diagnosis of your XR 's shifting problem, but it sounds like one of the shift forks is binding when the engine reaches full operating temperature. When shifting through the last three gears, one of the forks slides in one direction to engage fourth gear, moves back to a “neutral” position in fifth gear and then slides in the other direction to engage sixth. If that fork is binding due to heat expansion, it would make all three of those shifts difficult. The problem, of course, could lie elsewhere in the transmission, but the engine will have to come apart one way or another.

No-day-at-the-Beach Bar

I just read your review of the 2004 HarleyDavidson Road King Custom FLHRS, a very accurate article with two exceptions. Earth to Cycle World on the California Beach Bars that you slammed: We’ve been installing these bars for years to improve the look and ride of this bike. I have personally ridden long distances on a Road King equipped with Beach Bars and they are great. This bike is not a race bike like those that you usually favor. The real test is the bike’s sales rate: I cannot keep them in stock.

Second is your dislike of the seat. The seat is intended primarily as a solo seat that looks and functions well for the driver. If you are going to have a passenger, buy them a nice seat that you can swap out. The seat is held on with just one bolt. Take a weekend off from your speed bike and take the new Road King Custom for a ride. You’ll be glad you did! And thanks for a great magazine. Joe Basinait, Sales Manager Harley-Davidson of Jamestown Jamestown, New York

All of us here appreciate your compliment about the magazine, Joe, but you apparently have a complete misperception of the way we evaluate bikes.

First of all, I hope you don’t think we would publish a “test" of any motorcycle without having ridden it. Several of our staffers spent quite a bit of time on the Road King Custom, and 1 put almost 2000 miles on it, including one 800-mile day. Everyone who rode the bike complained about the Beach Bar, and even some of Harley-Davidson s own employees had less-than-kind things to say about that particular handlebar bend. Even a few people who just sat on the Custom commented on the unnatural feel of the handlebar. You may have ridden long distances on a Road King with these bars, but that model's windshield greatly reduces the rider’s need to squeeze the handgrips as tightly at highway speeds. Those handlebars might work acceptably for you, but we can't recommend them to our readers.

FEEDBACK LOOP

I enjoyed your test of the Harley-Davidson Road King Custom in the March issue of Cycle World. Great photos, too! A couple of notes, though. You claimed that the 88-inch Custom is equipped with the same freer-flowing mufflers used on the limited-edition 103-inch Screamin’ Eagle Road King and Electra Glide, and that this is why the Custom makes a little more horsepower than the other FL models. Actually, the Road King Custom uses the same touring mufflers (part nos. 65546-98A and 65547-98A) as the FLHRC Road King Classic and FLTR Road Glide. Also, your specifications page erroneously listed the Custom’s warranty as 12-month/unlimited mileage. All 2004 Harley and Buell motorcycles come with a 24-month/unlimited-mileage factory warranty. Just wanted to set the record straight. Paul James Harley-Davidson Motor Co. Milwaukee, Wisconsin

Thanks for the correction, Paul. 4s far as the Custom’s mufflers are concerned, I received some bogus information that I should have investigated more thoroughly. The warranty error, however, was simply an oversight on our part. My apologies if either misstatement caused The Motor Company any inconveniences.

As far as your comments about the seat are concerned, they simply don't wash. The seat clearly has a passenger section, the hike is equipped with passenger footrests, and nowhere in the Custom ’s owner’s manual or promotional literature is the hike referred to as a solo model. Truth is, the seat was designed for style first and foremost, with passenger accommodations an afterthought. Yes, Custom owners wishing to carry passengers in comfort can buy another seat, but they shouldn 7 have to do so, just as they shouldn ? have to change handlebars. I also notice that you used the term “swap out” when mentioning the acquisition of another seat; does this mean you will give a Custom owner a full refund on the stock seat? If not, it isn't a swap; it’s a purchase, a transaction that puts more money in the dealer ’s pocket.

ToolTime

It’s not a “tool,” exactly, but the first time you use it, you won’t care what it’s called; you’ll love it. It’s Meguiar’s ScratchX, a cream designed to remove light scratches and swirls from painted surfaces. It’s the best product of its type I’ve ever seen.

Most other similar products contain abrasives that, in essence, “sand” scratches away, so they also tend to turn the surface dull and remove some of the surrounding paint in the process. But not only does ScratchX contain no abrasives, it actually leaves the surface at least as glossy as it was beforehand, if not more so. And it almost magically removes scratches, dead paint and other surface contaminants with a minimum of elbow grease. Obviously, it can’t remove deep scratches or replace missing paint, but I’ve used it to successfully eradicate all kinds of surface blemishes—dull spots on gas tanks caused by a tankbag or a riding jacket rubbing against the paint; marks on the sides of a saddlebag put there when the bag brushed against a painted, rubber or wooden surface; paint that got on a helmet when it accidentally bumped into an open garage door or overhead sign at a gas station. After I’ve removed those blemishes, the surface looked and felt exceptionally smooth, like it had just been waxed. Despite that, you should always wax the affected area after using ScratchX, but you’ll have to remind yourself to do so, because the surface will already have a nice gloss.

ScratchX is available in a 7-ounce tube at most auto-parts stores for around $7. If you’d like more information, you can contact Meguiar’s by dialing 800/347-5700 or logging onto www.meguiars.com. -Paul Dean

Finally, the fact that I enjoy sportbikes doesn 7 mean I don 7 appreciate, understand or like Harley-Davidsons. I learned how to ride on a '49 Hydra Glide in 1958 and bought my first H-D, a ’58 Sportster, in 1963. I built pieces for Harley choppers at a bike shop I managed between 1965 and 1968, and have tested dozens of Harleys since entering the magazine business in 1973. I was the founding editor of Big Twin, an all-Harley magazine we published between 1993 and 2000, and 1 currently produce Power & Performance: Harley-Davidson, an annual H-D hop-up magazine. I know Harleys, Joe. And 1 also know an impractical handlebar when I grab onto one.

Taming tank-slappers

What’s the best thing to do in case of a tank-slapper? I’ve heard from the MSF that you should slow down and put your weight forward, while other motorcyclists say you should accelerate out of it. What’s the science behind tank-slappers and how do you get out of them? John Hopper IV Wall, New Jersey

Though I normally concur with the riding advice dispensed by the MSF, I have to argue with the notion that slowing down and putting your weight forward is the best way to get out of a tank-slapper. Based on my experiences, and those of every’ skilled rider I know who has dealt with this phenomenon, that’s usually the worst thing you can do. The accepted method of coping with tank-slappers is either to accelerate if possible or at least maintain a steady speed.

Tank-slappers occur when something causes the front wheel to be momentarily deflected off-center, most often when cornering at higher speeds. The self-centering “caster” effect of front-wheel trail wants to snap the wheel back to center; but as it reaches the straight-ahead position, the wheel-with the help of its attendant front-end mass, including fork legs, brake rotors, calipers, fenders and such-has so much momentum that it goes past center. The trail tries to bring it back to center, but its momentum again carries it past the straight-ahead position. This happens over and over again in rapid sequence, with the speed of the motorcycle supplying the energy that makes each back-and-forth cycle progressively greater than the previous one.

Meanwhile, as this dynamic develops, the entire bike starts waggling back-and-forth as the sideto-side oscillation of the front end induces a reactive chassis response. The problem usually is made even worse by the rider, whose arms serve as a conduit that delivers some of the force of the front-end oscillations into the chassis, and vice versa.

Slowing down or braking exacerbates the problem by shifting more weight onto the front wheel. That added weight gives the tire more traction, which allows its oscillations to have a greater effect on the chassis. What’s more, braking or slowing tends to thrust the rider forward, making him stiffen his arms, which then deliver more feedback from front wheel to chassis and back again.

This is why it’s advisable to avoid braking or slowing, and to resist your natural instinct to stiffen up. It’s a hard thing to do, but the best technique is to remain relaxed, stay on the throttle and off the brakes, and just let the handlebars waggle loosely in your hands. That gives you the best chance of enduring a tank-slapper without suffering any serious outcomes.

El richo Bandito

This past fall, I purchased a 1998 Suzuki Bandit 1200, and I really enjoy the bike except for one problem. When stopping hard (a regular stop, not a stoppie), the engine dies. It does this when the engine is cold or hot, when the gas tank is full or close to empty, and whether I’m stopping from 10 mph or 70 mph. After some cranking, the engine will start up again and I’m on my way. Any suggestions? James Johnson Appleton, Wisconsin

In all probability, the linkage that operates the cold-start enricheners on your Bandit ’s carburetors is improperly adjusted. When you turn the enricheners on, the linkage lifts a plunger in each carb that opens a large passage in the carb’s throat, just ahead of the throttle slide. The passage leads down into the fuel in the float howl, and when it’s open, intake vacuum draws extra fuel up into the intake tract, richening the mixture for cold starting and running. When the enricheners are turned off, the linkage is supposed to make each plunger fully close its passage, preventing extra fuel from getting into the intake stream. If the plungers do not fully close, some fuel will he drawn in to the intake, making the idle mixture slightly rich, though probably not enough so to cause stalling. But when the motorcycle undergoes hard braking, the fuel in the float bowl is thrust forward with enough violence to thrust some of it up into the enrichener passages where, aided by the high level of intake vacuum caused by having the throttle closed while braking, it is sucked up into the intake tract, causing an excessive rich condition that stalls the engine.

The solution is pretty simple: Adjust the linkage so that all four plungers are fully closed when the enricheners are turned off. If that fails, it’s likely that the neoprene seals on the plungers have deteriorated and are allowing fuel to leak past. Obviously, that will call for the replacement of those seals. □

Got a mechanical or technical problem with your beloved ride? Can’t seem to find workable solutions in your area? Or are you eager to learn about a certain aspect of motorcycle design and technology? Maybe we can help. If you think we can, either: 1) Mail a written inquiry, along with your full name, address and phone number, to Cycle World Service, 1499 Monrovia Ave., Newport Beach, CA 92663; 2) fax it to Paul Dean at 949/6310651; 3) e-mail it to CW1Dean@aol.com; or 4) log onto www.cycleworld.com, click on the “Letters to the Editor” button and enter your question. Don’t write a 10-page essay, but if you’re looking for help in solving a problem, do include enough information to permit a reasonable diagnosis. And please understand that due to the enormous volume of inquiries we receive, we cannot guarantee a reply to every question.