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Paul Dean

Obnoxious interruptus

I have a 1976 Honda CB550 that has the most obnoxious turnsignal beeper ever known to man. I was wondering if I could disconnect or remove it without losing the use of the turnsignals. I hate it, other people hate it, and it’s just one more reason for Harley riders to beat me up! Any help would be appreciated.

Bob Fuchs Plano, Illinois

For a couple of years back in the middle 1970s, Honda equipped some of its streetbike models with what it called a turnsignal warning buzzer. This was considered a safety feature, the idea being to prevent anyone from riding along mile after mile with a signal light flashing. But about this same time, Yamaha introduced selfcanceling turnsignals, a technology that most riders found far less bothersome than a buzzer; and within a year or two, other manufacturers, including Honda, began equipping many of their models with self-canceling signals, and the buzzer disappeared forever Fortunately, you can easily rid your CB550 of the buzzer without affecting the operation of the turnsignals. The buzzer is located under the front of the gas tank and is separate from the turnsignal flasher, which is under the seat. If you have trouble locating the

buzzer once you have removed the gas tank, just switch on the turnsignals and follow the sound you know so well. Then, unplug the two wires that lead out of the buzzer, undo the bolt holding it in place and toss the whole works into the nearest trash can.

Now, please understand that it has been more than two decades since I've dealt with one of these buzzers, and I wasn 't able to contact anyone who remembers the specifics, so my recollection is a little fuzzy; but I'm about 90

percent certain that if you just unplug the buzzer, the turnsignals will continue to operate. If they don 't, however, the fix is easy; simply make a short jumper wire that has a male connector on each end and plug it into same female connectors that previously contained the two buzzer wires.

After this quick and easy modification, the turnsignals should operate quietly, leaving you free to work on the other traits that seem to make Harley riders want to beat you up.

Zephyr forephyr

I have a 1991 Kawasaki Zephyr with 7000 miles on the speedo that I bought used but in mint condition. The bike runs great when warmed up but is very difficult to start when cold. It sometimes will start and stall again and again, often up to eight or nine times before it finally catches hold, then it races up to around 5000 rpm. If I back off on the choke it stalls, and if I even touch the throttle it stalls. I took the bike to two different mechanics who checked the chokes, cleaned and synchronized the carburetors, checked the valve clearances and installed hotter plugs, but nothing has helped. To me, it sounds like the engine is starving for fuel and needs bigger jets, but which ones? Can you help? Lech Lipski

Babylon, New York

In 1991, Kawasaki sold two Zephyr models in the U.S.: a 550 and a 750. Both used air-cooled engines that relied on two-valve-per-cylinder technology that was rather dated even then. Without the liquid-cooling and sophisticated cylinder-head designs of the

more modern bikes of that era, the Zephyr needed ultra-lean carburetion just to meet federal exhaust-emissions regulations. The end result was the very characteristics you describe with your bike-reluctant starting and practically non-existent throttle response until the engine is fully warmed.

Fortunately, these symptoms are easily-and, at around $100, fairly cheaply-remedied. Dynojet manufactures carburetor recalibration kits for both the 550 and 750 Zephyrs, and Factory offers them for the 550. A fter the installation of one of these kits, your Zephyr will not only start up more easily and have better throttle response when cold, it also will perform slightly better when warm.

Duck mating call

This isn’t a maintenance question, but I’d like to know something about a Ducati. After reading so many wonderful things about Ducatis, I decided to unload my Yamaha FZR600 and buy a 900SS. It’s a used, low-mileage ’97 I got from a private owner at a reasonable

price. It runs great except that it makes an awful rattling noise when it idles. The noise seems to be coming from the transmission, and it sounds like something is loose in there. It’s worse when it’s in neutral and the clutch is out, but it’s still very loud in any gear when idling with the clutch in. I don’t know anyone around here who is very savvy about Ducatis, and the guy I bought it from says this noise is normal. I did meet a guy who was riding a 916 that made the same kind of noise as my bike, but I still can't imagine that all that racket is typical. Am I crazy or what?

Don Markham Bozeman, Montana

I haven't the faintest clue whether or not you 're crazy, but I do know that the noise your 900SS makes at idle indeed is perfectly normal. It is the sound of the clutch plates rattling back and forth in the clutch hub.

To understand why your Ducati makes this noise and your FZR did not, you need to know a few basics about clutch design and engine idling char>

acteristics. Most modern bikes use a multi-plate clutch in which wide tabs around the periphery of the drive plates fit into slots in the outer clutch hub, and smaller tabs around the inside diameter of the driven plates fit into narrow slots on the inner clutch hub. There is sufficient clearance between the tabs and slots to prevent the plates from hanging up during disengagement, and at idle, that clearance allows the entire clutch pack to rattle back-and-forth as engine rpm fluctuates.

And why, you ask, does the rpm fluctuate? Every time a cylinder fires, the crankshaft speeds up, then gradually slows down until the next cylinder fires. So, even though the tachometer may indicate a steady rpm at idle, the engine actually is constantly speeding up and slowing down. And that sudden, frequent variation in rpm causes the clutch plates to rattle in their slots.

In a wet clutch, the oil acts as a cushioning medium that dampens the impact between the plates and the hubs, while also helping to suppress any noise that might result. But with a dry clutch, the plates are free to rattle unabated. And when that dry clutch is attached to an engine that has as much idle-speed

variation as a big, high-performance VTwin, the amount of rattling can be considerable. The reason the noise changes slightly when the clutch is disengaged with the transmission in gear is that only the outer clutch hub is then rotating; the inner hub remains stationary until the bike starts moving.

Clunking Bandit

I bought my 1997 Suzuki Bandit 1200 new, 9000 miles ago. At around 7500 or 8000 miles, I became aware of a clunking noise when I shift from first to second and second to third. The clunk is not as loud between second and third as it is between first and second, but it occurs about 90 percent of the time, and the higher the rpm, the louder the clunk.

I am not an aggressive rider and I have taken excellent care of the bike since day one. The chain has always been lubed and adjusted to have 1 inch of play while on the sidestand, just like the manual advises. The clutch master cylinder is full, and the clutch feels the same as it always has. The ironic thing is that if I don’t use the clutch when shifting, there is no clunk. I would appreciate any suggestions in regard to getting rid of this noise besides taking the bike to a me-

chanic and having him perform exploratory surgery on the tranny. Even though I’ve been shifting at much lower rpm since I became aware of the noise, could I have caused any harm to the drivetrain during this past 1500 miles?

Robert Seinfeld Miami, Florida

There's a name for the tactic one must use when attempting to diagnose a noise without actually hearing it: guesswork.

All you can hope for is that the guess is an educated one. And my best guess is that there is nothing wrong with your Bandit’s driveline.

Based on the content and tone of your e-mail, I suspect you are a very conservative rider who changes gears carefully and deliberately. And while you are to be applauded for the care and concern you have for your bike’s well-being, shifts made rather slowly tend to cause clunking noises in the driveline.

Ideally, upshifts should be completed, from clutch in to clutch out, in a fraction of a second. I ’m not talking about a full-on, drag-race-style speed shift, but rather a quick, crisp tug on the lever that begins the very moment the clutch starts being disengaged. This technique

ensures that the speed differential between the two gears being engaged is minimized. If the shift takes too long, however, that differential can be huge. This happens because the speed of one of the gears is dependent upon rearwheel rpm, while the other is controlled by engine rpm. If the shift is done too slowly, the engine will drop down to or near idle while the speed of the rear wheel remains virtually constant. Thus, the engaging gears have enough speed differential to send a shock wave coursing throughout the entire driveline as they come together-a loud clunk, in other words.

You hear no clunk when you don’t use the clutch because clutchless shifting requires a near-perfect speed match between the engaging gears. The clunk is louder during the 1-2 shift than it is during the 2-3 because the ratio gap between first and second is greater than between second and third. And the loudness of the clunking increases with engine rpm because the speed differential is greater than it is at lower rpm.

I suggest you try making upshifts as quickly as is reasonable, stopping just short of banging speed shifts. If that technique still results in the clunking noise, then perhaps I am wrong about your shifting technique and something really has gone awry in the driveline. In that case, a good place to look would be in the dampers in the rear wheel; these are the big rubber cushions that fit between the sprocket carrier and the rear hub. They may have begun to break or deteriorate, allowing the entire sprocket carrier to jump around enough to cause the clunk you are hearing.

Without warning

I was shocked to read your reply to Eric Sindelar (“Liar, liar, cut the wire,” August, 1999) when he asked about a problem with the low-oil warning light on his ’98 Yamaha YZF-Rl. I thought it was irresponsible of you to tell him to disconnect the light just because neither you nor Yamaha knew how to fix the problem. If you can’t provide better answers than that, you shouldn’t be allowed to print them. John R. Siegel

Cheektowaga, New York

Actually, I thought my answer made perfect sense. Until Yamaha or someone else comes up with a fix for the premature low-oil warning problem, running with the light disconnected offers no disadvantages when compared to what you get with the vast majority of other motorcycles, which have no such warning systems. Those bikes rely entirely on either a dipstick or a sight glass for verification of oil level, and the latter is precisely what an R1 rider is left with when the warning light is disconnected. Plus, he doesn’t have to endure the distraction of a red light and a flashing LCD that are illuminated for no good reason. I stand by my response.

Engagement proposal

Do you know where I can purchase undercut gears for a Suzuki GSX-R1100 transmission? I replaced second gear once with a stock Suzuki gear, but I’ve been told that undercut is the way to go. Any help will be appreciated. MARKYTA Posted on America Online

For those of you who do not already know, undercutting refers to the reverse beveling of the gears ’ engagement dogs. In other words, the contact surfaces of the dogs are angled so they’re slightly wider on their outer edges than on the inner. This beveling causes the gears to be drawn together as the engagement dogs make contact with one another during a shift, resulting in more-positive gear engagement and less chance of gear rejection. The amount of beveling varies from 5 to 10 degrees, depending upon the diameter of the gear and the bike’s intended usage-drag racing, roadracing, etc.

I’m not aware of anyone who sells undercut gears for GSX-Rs, but I know of two companies that will modify your bike’s stock gears. Star Racing (726 Crisp Dr., Americus, G A 31709; 800/841-7827) will undercut the upshift side of your 1100’s gear dogs for $250-a price that includes magnafluxing the gears to check for cracks. Murdoch Racing (625 Pinellas St., Clearwater, FL 33 756; 727/443-5330) charges $195 to undercut the upshift side of the dogs, and another $40 if you want the gears magnafluxed. If your intended usage is roadracing, Murdoch also suggests having the downshift sides of the dogs undercut, which tacks another $100 onto the charges. É3