Service
SERVICE
Paul Dean
Width matters, too
I own a 2003 Yamaha YZF-R6 and was wondering what is the widest tire that I can fit on the stock wheel? I want to keep using Dunlop D208ZR tires, but I would like to be able to fit 200-series rubber on the bike. Thanks for the time and the help. Robert Maxwell Louisville, Kentucky
The real question here is why you would want to put a 200-series rear tire on one of motorcycling’s most perfectly balanced sportbikes. The stock rear tire is a 180/55ZR17 fitted on a 5.5-inch-wide wheel, whereas the 200-series tire is a 200/50ZR17 that’s n/i6-inch wider than the 180 and should be mounted on either a 6or 6.5-inch-wide rim.
I don’t know whether or not a 200-series tire will fit in the swingarm of an R6, simply because I don’t know anyone who has tried to do such a thing. But the problems with this modification go beyond just making the tire fit. I doubt that you could squeeze the bigger tire between the sides of the swingarm; and even if you could, you probably would not be able to maintain correct chain
and wheel alignment. What’s more, unless you use a wider wheel, the sidewalls will get pinched together too tightly to let the tread retain its intended curvature; moreover, the added tread width would cause the contact patch to shift farther off the centerline of the tire
when the bike is leaned over. Those two factors alone would significantly alter the R6’s handling characteristics, and such changes are not likely to be positive. Unless you intend to do something out of the ordinary with your R6, my advice is to forget the 200-series tire.
Down to the wire
I swapped the turnsignals on my 2002 Honda CBR954RR for smaller, more aerodynamic ones. Since that change, the bike’s headlight fuse tends to burn out and the battery often goes dead. This doesn’t happen on a daily basis, but has occurred frequently since I made that modification. I also noticed that the stock front turnsignals had three wires but the new ones only had two. What can I do to fix the problem? Carlos Marquez
Miami, Florida
The 954 s stock turnsignals are not just directional indicators, they also serve as running lights. They use dual-filament bulbs much like those in a typical taillight/stoplight assembly, wherein one filament is illuminated any time the ignition is on, and a second, brighter filament blinks when its turnsignal switch is activated. This is why the stock unit has three wires: One hot wire for the running light, one hot wire for the turnsignal, with a third wire as ground.
Several conditions could be causing your 954 ’s electrical problem, including a wiring glitch that you inadvertently created-such as plugging one of the wires into the wrong connector-when installing the aftermarket turnsignals. If that ’s the case, I’m afraid I can 't offer much help; I ’m unable to examine your rewiring job, and there are too many possible wrong-connection options for me to cover here. All I can suggest is that either you very carefully go over the modified wiring or else have it inspected by a mechanic who understand electrics.
If the wiring is otherwise okay, it’s my best guess that when you hooked up the aftermarket signal lights, which have only two wires-one hot and one ground-you left the two unused hot wires dangling. Normally, all hot wires have female connectors that prevent the actual wire ends from accidentally touching any grounded metal surface or another hot wire. But if you simply clipped all the wires and used something other than the stock connectors, the bare ends of the unused dangling wires could occasionally touch something they should not, thereby either blowing a fuse or discharging the battery. You need to dig back into the wiring and ensure that all of your connections are tight and correct, and that the stock running-light wire on each side is adequately insulated.
Braking news
I was recently told by a friend that the drum rear brakes like those on early-’80s streetbikes should have significant pedal travel. He says the pedal should easily pivot 45 degrees before the shoes begin to make contact with the drums to help ensure that the rear brake is used less than the front.
My understanding of proper brake use is that under normal street riding, the rider should apply even braking between both front and rear as conditions warrant. I’ve experienced excessive pedal travel on an ’82 Suzuki GS550 that allowed me to clip my shoe in a right-hand corner, giving me a scare. Is there a legitimate reason for excessive brake-pedal travel on older streetbikes? Lee Yarger
Muncie, Indiana
No matter how old any motorcycle might he or what kind of braking system it might have, 45 degrees of brake-pedal travel-or anything even remotely approaching that amoant-is way too much. The pedal on a mechanical rear brake should not have to pivot significantly farther than its counterpart on a hydraulic disc-brake system. Different riders have different preferences, but most favor just a few degrees of travel before the brake begins to engage. The only requirement for pedal freeplay is a complete absence of brake drag when the brake is not in use.
Your friend’s notion of using pedal travel to control front-to-rear braking balance is utter nonsense. Unless the bike in question has a linked braking system, the proportion of braking is regulated by the pressure applied by the rider’s right foot and right hand, not by how far those appendages have to move. Under normal circumstances, applying an even amount of front and rear braking as you suggest is an acceptable practice, but not necessarily ideal. Because so much of the total weight of bike and rider is transferred forward during braking, the front brake offers far more stopping power than the rear. Riders who are not accustomed to using a lot of front brake usually are ill-prepared to do so when
called upon to make a panic stop. A lot of riders are needlessly fearful of frontbrake usage, but in certain situations, that right-side hand lever can be a motorcyclist ’s best friend.
The Mighty (noisy) Ducks
I love the performance and aesthetics of Ducati motorcycles, but when I looked at a couple of models before buying my last bike, the noise the clutch made in neutral was too disturbing. The salesman mumbled something about a dry clutch, but what I heard was, “I really don’t know what makes that noise.” Can you tell me why Ducatis make such a racket?
Steve Wyatt Posted on America Online
The salesman was correct: The rattling noise given off by Ducatis is caused by their dry clutches. The vast majority of other motorcycles-Japanese bikes in particular-use multi-plate clutches intended to operate when the fiber plates are soaked in oil. This simplifies primarydrive design, because the clutch assembly does not have to be sealed off from the oil used to lubricate the primary-drive gears or chain. In addition, the oil also serves as a damping agent that helps reduce primary-drive and clutch noise.
Oil also is a friction-reducing agent, however, which works against the principles governing the operation of a clutch, which requires friction to work properly. This is why most tuners prefer dry clutches for competition use. All other things being equal, dry clutches generally can handle more power than wet clutches, plus they disengage more completely and tend not to drag as easily when overheated. And because they are not constantly bathed in hot engine oil, they tend to run cooler, especially since they can be exposed to the flow of air outside the engine rather than contained within a sealed cover But they’re also much noisier. Without oil to dampen them, the plates rattle back-and-forth in the clutch basket. This is especially so at idle, where variations in rpm during each engine revolution are at their greatest. Those fluctuations are made even more dramatic by the uneven firing impulses of a 90-degree V-Twin. Every time a cylinder fires, the engine speeds up, which causes the tangs on the clutch plates to be thrust to one side of their slots in the basket; as the engine slows down between power pulses, the plates tend to shift to the other side of the slots. Then, when the other cylinder fires, the plates are thrust back in the other >
direction. Although that constant backand-forth movement takes place within the very small clearance between the plates and the clutch basket or hub, it results in a significant rattle. When the clutch is engaged with the engine in neutral, the entire clutch pack shifts back-and-forth, so the noise has a comparatively heavy sound; when the clutch is disengaged, the plates are free to rattle individually, so the sound changes to a higher-pitched ‘ jingling ” noise.
Having positioned its motorcycles as street-going racebikes, Ducati has chosen to use dry clutches. The noise they make does no damage and causes no more mechanical problems than a wet clutch, but for the aforementioned reasons, some people are put off by it.
Brake exorcism
I am a long-term CW subscriber who is being overwhelmed by a technical glitch involving my wife’s 1987 Honda 450 Rebel that has 29,000 gentle miles on it. Most importantly, it has a brand-new OEM front-brake rotor and pads. These items were installed because, at lowerspeed applications of the front brake, the brake howls in a loud, deep tone, not with a squeal/screech like my old BMW used to give off. The dealer even sanded the new pads, but the noise is back like a recurring nightmare. Could it be a bent fork, a defective caliper/piston assembly or is the bike just haunted? Dan Baizer Redding, California
A bent fork wouldn’t cause any spooky howling noises, but a tweaked or sticking caliper might. The 450 Rebel ’s front brake uses what is often referred to a “single-
action ” caliper that has pistons only on one side; the pads that contact the other side of the rotor are stationary. This requires the caliper to "float,” meaning that instead of bolting solidly to the fork leg, it attaches with pins that allow it to shift from side-to-side. When the brake is applied, the pistons push the movable pads against one side of the rotor, and the caliper reacts by shifting slightly in the opposite direction until the stationary pads apply equal pressure to the other side of the rotor If however, the caliper-mounting pins are rusted, corroded or caked with dirt, the caliper might not be able to shift side-to-side, resulting in uneven braking that also could be the source of the strange noises you hear during light brake usage.
You need to remove the caliper, then closely inspect and clean the mounting pins and their mating holes in the caliper body. Apply a small amount of light grease to the pins before reinstalling the caliper, then make sure the caliper body slides freely on the pins.
FEEDBACK LOOP
I read with interest the letter from Jamie Bray ("Fuel-infection") in the September issue and his problem with the intermittent rich-running condition on his 2000 Honda RC51. Your response was well-thought-out and logical, but when Jamie said that turning off the ignition and restarting the engine eliminated the problem, I was reminded of a servicetech briefing we had on the 2000 CBR929RR and RC51 when I was Press Manager at American Honda. As I recall, the first-generation fuel-injection programming on these bikes only sampled air density (atmospheric pressure) one time-when the ignition was turned on. (In the 2002 model year, the system was modified to sample the air at regu lar intervals.) So in theory, if a rider started out at sea level and then rode above 7000 feet, he might experience rich running until he stopped and restarted the engine. I don~ know if Jamie's riding took him through significant elevation changes, but I thought it was worth mentioning to you for future reference. Pete ter Horst Asheville, North Carolina
Fabulous input, Pete. That type of insight can be valuable not only to Jamie Bray, but to anyone riding a 2000-01 RC51 or 929. I know that you no longer are at American Honda, having chosen to be part of the wonderful fund-raising work done by the Pedi atric Brain Tumor Association, but you obviously have stayed in touch with motorcy cling. We appreciate your sending us this useful information.
If the noise still persists, the caliper may have gotten distorted. This condition is harder to diagnose, hut it, too, could cause noise when braking. The caliper must allow the pistons to be perfectly perpendicular to the face of the rotor If they are not, the pads can chatter under light pressure, resulting in a loud noise. If you still have the old brake pads, check
them for significant uneven wear~ which would indicate a misaligned caliper. You might even be able to detect uneven wear on the newer pads. If you find any such wear, you `ii have to replace the entire caliper-although locating a new one for a 16-year-old motorcycle might be just as much of a challenge as finding the cause of the noise.
No shift, Sherlock
I have a 2002 Honda Shadow Spirit 750, and ever since new, it has had a shifting problem. Initially, it often would not fully engage when I’d shift up into fifth gear, but after about 1000 miles, the problem changed to third gear. Fifth gear was fine but, on occasion, third gear wouldn’t engage when I lifted up on the shifter.
I now have 5700 miles on the bike and this problem occurs 30 to 40 percent of the time. When 1 lift up on the shifter while in second gear, nothing happens; the lever goes all the way up, but no gear engages. If I release the shifter and lift up again, third gear will engage. This only happens with third, and it always engages on the second lift.
The service manager at my dealership said this sometimes happens and that it’s no big deal. He suggested I hold the shifter up until after I release the clutch to help the gears engage. He said I should do this in all gears, on all bikes. I complained to him about this problem three times-twice during the warranty period-and nothing was done. He wouldn’t even have a service tech check it out! And now my warranty has expired. What’s going on here? Andrew Hoehn Waterford, Michigan
What 's going on is yet another example of a dealer/mechanic who is either incompetent, stupid or an out-and-out liar-or all three. His suggestion about the way you should shift all motorcycles is ludicrous, and the shifting problem you describe is one that any real mechanic should be able to remedy in an hour or so.
Recall Roster
NHTSA Recall No?03V230 Big Dog Chopper Model year: 2003 Number of units involved: 854 Problem: On certain motorcycles, the fuel-tank mount may have been improperly welded. This can cause the tank to fail, creating the possibility of fuel spillage, which could result in a fire. Remedy: Dealers will remove the tank and ship it to Big Dog for repair. Big Dog will reweld the mount, repair the paint and return the tank to the dealer for reinstallation. Owners who do not receive the free remedy within a reasonable time should contact Big Dog at 316/219-6584.
As with virtually all motorcycles, the gears in your Shadow are selected via a ratcheting mechanism that rotates a shift drum, which, in turn, moves the gears in the transmission. If the ratchet device is not properly centered, normal movement of the shift lever will try to rotate the shift drum too far in one direction and not far enough in the other. The former is not a problem, because the ratchet mechanism has a positive stop that prevents it from rotating the drum too far; but if the drum is not rotated far enough, the gears often won’t interlock. When that happens, the shift lever has to be returned to the center position and then moved once again so the ratchet can re-engage and rotate the drum the rest of the way. You can liken this process to using a ratchet wrench: If you aren ’t able to turn a bolt or nut far enough with just one swing of the ratchet handle, you have to move the handle back in the other direction and then take another swing at it.
When the ratchet mechanism is only slightly off-center, the symptoms often show up while shifting into just one specific gear and not the others. The degree and rate of required gear movement in the transmission is not the same for all shifts, which makes some gears easier to engage than others. This is why the second-to-third shift on your Shadow is troublesome while all the others are not.
Practically all shift mechanisms incorporate some kind of adjustment provision-often nothing more than an eccentric anchor pin for the shift-lever return spring-that allows the ratchet to be centered. You need to find a capable mechanic who understands this simple concept and knows what to do about it. □
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.
