Service

SERVICE

Bringing up the rear

PAUL DEAN

QI don’t consider myself a genius or a moron when it comes to cycle lingo, but I just don’t understand what is meant by the term “rearsets.” I thought that was where passengers put their feet. Why would you want them to be adjustable? Don’t you like them where you put them? Aren’t you the only one who rides your bike? I know I am. And does anyone make them for my ’86 Honda Nighthawk? Please help me understand this. Jim Fortini Carlisle, Pennsylvania

A That terminology dates back to an era in which production motorcycles had rider foot controls positioned for comfort, not for competition. The controls usually were located too low and too far forward for roadracing in particular, so riders who wanted to convert their bikes for that type of competition-or even to turn their machines into eafé-racers, which were early, home-built forerunners of factory sportbikes-would either modify the stock foot controls or replace them with new ones that “set” everything higher and farther to the “rear.” Hence the term “rearsets.”

Eventually, the motorcycle manufacturers began producing sportbikes configured much like purpose-built roadracers, including foot-control locations, greatly reducing the demand for rearsets but not eliminating it altogether. Some riders still desire different controls, and for different reasons-adjustability, lighter weight, added cornering clearance or merely more bling.

And no, rearsets are not available for your ’86 Nighthawk. Nice bikes, those, but not exactly roadrace fodder.

Idle thoughts

QI bought a 1983 Honda VF750F Interceptor with 3800 miles on it that had been stored for more than 20 years. I disassembled and cleaned most of the running gear and had the fuel tank cleaned. I cleaned and rebuilt the carbs and replaced the oil, filter, brake fluid, brake pads, coolant, chain and tires.

Upon starting it, I noticed a clacking noise coming from the clutch side of the engine. I took off the sidecover, removed and reassembled the clutch and found nothing apparently amiss. The noise is comparatively quiet when the bike is cool but rapidly becomes louder as the engine reaches operating temperature.

It runs fine and appears to have good oil pressure, does not overheat, etc., but I am concerned with the racket. The noise is most prevalent at idle, no matter if the bike is in gear or not, but it doesn’t do it when moving in gear. Pulling in the clutch diminishes the clacking slightly when the bike is idling in neutral, but it is present at any engine speed below 1500 rpm. Jim MacDonald

Satsuma, Florida

A Noises like this are reasonably common and caused by a combination of uneven idle and worn clutch plates. Actually, some bikes make these sounds even when every aspect of their engines is in tip-top condition.

As an engine idles, it speeds up very slightly when any given cylinder fires, then gradually slows down until the next combustion event takes place. This is most prevalent in single-cylinder engines, since they fire only once in every 720 degrees of crank rotation. It generally occurs to a much lesser extent on inline four-cylinder engines, which fire four times at even intervals during that 720 degrees. But your Interceptor does not fire at even intervals. Its 90-degree V-Four engine has a 360-degree crankshaft that produces an uneven (90-270-90-270-degree) firing sequence, which means its rpm varies even more dramatically than an inline-Four’s at idle and very low engine speeds.

This is where worn clutch drive plates enter the picture. When new, the plates fit in the slots in the outer clutch hub snugly enough not to be affected by fluctuations in idle speed. But as the tabs on the plates wear, they fit more loosely in the slots in the outer clutch hub. This allows the entire clutch pack (along with the transmission mainshaft) to jiggle back-and-forth in the hub as the engine rapidly speeds up and down. The noise changes when you disengage the clutch because that separates the plates so that only the drive plates chatter. Plus, if the carbs are improperly synchronized, idle-speed variations will be even more dramatic, making the noise even louder.

My advice is to synch the carbs as accurately as you can and check-and if needed, replace-the clutch plates and outer clutch hub.

The noise then might not go away ■ entirely but should be diminished enough to make you happier with your vintage Interceptor.

The cable guy

QI have a 1980 Honda CX500 Custom that I would describe as a “rat bike.” I’ve made numerous changes to it, such as installing “beach” handlebars, adapting a muffler from a Kawasaki ZX636, footpegs from a Yamaha FZR1000, an aftermarket headlight, etc. My current project is installing Kawasaki handlebar controls, but I’ll need to have custom throttle cables made up. I’ve located several sources for these but they are rather expensive. I have run into this problem before and would like to start making my own cables. Does anyone sell cable components and the tools needed to swage the fittings onto the cable ends?

Steve Parsell Lyons Falis, New York

A Call or log onto the website for the Flanders Company (626/7927384; www.flandersco.com), which has been selling separate cable components and cable-building tools longer than 1 can remember-and I have an exceptional memory. Never forget a thing.

I’m sorry, did you have a question about something?

The master of cylinders

Q About a year ago, you gave a

wonderful explanation of the differences between radial-mount frontbrake calipers and the traditional method of mounting, even providing excellent drawings of the two types. I now understand that part of the “radial revolution,” but I remain a bit confused about radial master cylinders. Could you offer an equally clear explanation of that technology, including what makes these master cylinders superior to the conventional ones?

Campbell Willingham Long Island, New York

AI have seen several different

claimed benefits of radial-pump master cylinders, such as increased leverage or the ability to have a larger piston diameter, but those qualities could easily be built into conventional designs. Really, the only significant advantage of the radial type is their greater resistance to flexing. When you squeeze the lever on a conventional master cylinder (above, right), the force you apply with your hand is inward, toward the handlebar; the piston, however, is oriented parallel to the handlebar, so the lever has to turn your squeezing force about 90 degrees to the left. This causes the entire master-cylinder assembly to flex, since it is mounted to the handlebar only on a relatively narrow perch. In fact, if you wanted to design a mechanism intended to flex such a mount as easily as possible, it would be hard to outdo a conventional master-cylinder arrangement.

Tool Time

Gee, I thought i had the entire ratchet spectrum covered. I’ve informed you of paim-size ratchets, geariess ratchets, ratchets with a VÁ-inch-drive stud on one side and a %-incher on the other, even ratchets with adjustable-length handles. But The Stanley Works (860/225-5111; www.stanleyworks.com) has come up with yet another take on the ages-old ratchet concept. It’s the Rotator, a ratchet that not only lets you turn the drive stud in the conventional manner-by swinging the handle back-and-forth-but also by twisting the handle. If you’re working in such tight quarters that there isn’t room even for the required 6-degree arc swing of the Rotator’s rubberized handle, you instead just twist the handle, which then rotates the stud. And no matter which way you twist the handle-either only clockwise, only counterclockwise or back-and-forth both ways-the stud rotates in the desired direction based on how you have adjusted the right/ieft switch on the back of the ratchet head.

Stanley tools are sold at most hardware and discount department stores, including Home Depot, Lowe’s, Target, Wal-Mart and Kmart, as well as at Pep Boys and numerous other auto-parts outlets. Prices vary slightly depending upon the retailer, but in its 3/s-inch-drive version, the Rotator sells for around $39; # a 1/4-inch-drive model goes for about $31.

A radial-pump design, however, eliminates practically all of that flex. The force you apply to the lever with your hand still is inward, obviously, but so is the force applied to the master-cylinder piston, which is perpendicular to the handlebar rather than parallel to it. In effect, the piston is “trapped” between the lever and the bar, with all of the forces acting in the same direction. Consequently, none or very little of your squeezing force is lost to the flexing of the master-cylinder mount, giving the brakes a more positive, solid feel. &

Recall Roster

NHTSA Recalls No. 07V296000 & 07V303000

Harley-Davidson XL1200L, XL1200N Model years: 2006-07 Number of units involved: 18,784 Harley-Davidson VRSCR Model year: 2006 Number of units involved: 2403 Problem: These motorcycles were built with a condition whereby the pant leg of some riders can have direct contact with the exhaust pipe. This could cause the pant leg to char or burn, which could lead to the possibility of injury to the rider.

Remedy: Dealers will add a new exhaust heat shield which provides additional coverage of the exhaust pipe. Owners who do not receive this free remedy may contact Harley-Davidson at 414/343-4056._