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How to hobble an FJ

I am 15 years old and totally committed to motorcycles. I have considerable experience riding smaller, under-185cc motorcycles in large, privately owned paved areas, so I know how to ride.

When I do get my license, I plan to use a motorcycle as my form of transportation and for fun on the weekends. I would like that bike to be an FJ 1100 or 1200, but I know you can’t hop off a poodle bike onto a two-wheeled rocket like an FJ or a GSX-R.

Because I won’t have the finances to buy a middleweight and then a big bike, selling each as I go along, I want to just buy an FJ and make one of the following modifications as an attempt to temporarily tame the beast while I learn to handle it. I had in mind: electrically disconnecting two cylinders, or installing a rev limiter set for about 5500 rpm, or installing an exhaust restrictor to cut the power. Which would you recommend? Lee Wommer Miami. Florida

We'd strong/y recommend that you learn about street riding on a smaller

machine. If vour finances are stretched, YOU might consider purchasing something like a used 500 Interceptor or GPz550for your first season or so. Such a bike would be affordable and offer more than enough performance. After all, either of these bikes is faster than all but the fastest machines of a decade or so ago.

If YOU absolutely must start with a big FJ, neither disconnecting two cylinders nor restricting the exhaust is an acceptable method of detuning the machine. While the rev-limiter would work, a better and simpler solution would be to restrict throttle travel, something that can easily be done in a number of ways. But once again, a smaller machine is a far better alternative.

Nighthawk handling improvements

After some months of serious contemplation, I have decided to retire my trusty old BSA from street service and replace it with a 1 985 Honda CB700SC Nighthawk S. However, before I do so. I’d like your advice on a few points.

First, what can be done to lessen the nasty effects of shaft-drive torque reaction on handling behavior? I’ve read about the ATK/Leitner system (with floating rear-wheel gearcase) and was wondering if there is anything similar but perhaps more accessible to the average rider?

Second, what overall suspension upgrades would you suggest, if any? My riding would consist mainly of highway miles with some occasional corner-bending thrown in for fun. Dave DeGaeta Jersey City, New Jersey

Without completely re-engineering a shaft-drive motorcycle, about all that can be done to minimize shaft-driveinduced suspension movement is to reduce suspension travel and run fairly stiff springing and damping. With the Nighthawk S, that's exactly what Honda has done. If you pay attention while riding it, you can feel the rise and fall of the Nighthawk 's rear end with throttle opening, but it's about as well-tamed as any current shaft-drive

bike. There's simply not much more you can do without making the rear suspension completely rigid.

Actually, everything about the Night hawk's handling is good enough that no immediate upgrades are needed. We'd suggest replacing the tires and shocks with better quality aftermarket items onl y after the stock ones wear out.

Sabre stiffening

I am interested in suspension modifications that might improve the handling characteristics of my 1984 V65 Sabre. My situation may be somewhat unique, so any help would be appreciated.

First, I enjoy vigorous sport riding, and things had been fine with the VF750F Interceptor I owned in 1 983 until circumstances dictated that I get a larger bike for two-up traveling. Second, I am a very large person (6’8” tall and 280 pounds) and have never read or found anything regarding how I might compensate for my size with modifications to my bike. The suspension presently bottoms pretty easily, and I take up quite a bit of travel just sitting on the bike. What would you suggest? Phillip C. Aldrich Lusk, Wyoming

With your weight, stiffer springing would definitely be in order. Alternative fork springs are available from ATK (723 Laguna Canyon Rd., Laguna Beach, CA 92651 ; [714] 4977525). Stiffening the rear suspension is more of a problem. Simply increasing the air pressure in the stock Honda shock far enough to compensate for your weight will lead to a harsh ride; better would be to swap the shock for one with a stiffer spring. We'd suggest using a Works Performance unit;

Works could tailor the damping and spring rate for your specific needs. The address is 873Ö Shirley, Nortbridge,

CA 91324; (818) 701-1010

Best forks

My company, Storz Performance, is the sole U.S. distributor for Ceriani FI motorcycle racing forks. I would like to take issue with a re-

ILLUSTRATION BY JIM CRAWFORD

mark made in the March, 1986, issue regarding the use of Marzocchi M 1 forks on the Cagiva Paso. Your article states, “Both front and rear suspensions use the best available components (a Marzocchi Ml fork in front . . .).”

Clearly it is a matter of opinion rather than fact that the Ml fork is superior to anything. If you will take note, Cagiva is supplying new 750 FI’s with Forcelle Italia (Ceriani) forks as standard equipment as shown in your Roundup section of the March issue.

I am certain that close comparison will show the FI Ceriani forks to be

superior to the M1 units, and in fact they are the choice of many GP competitors in Europe.

Steve Storz Ventura, Calif.

Our point would have been better made if we had referred to the Marzocchis as "high quality" rather than "the best available. " Ás you point out, the "best" label requires testing and comparison before it can accurately be applied.

If an y readers are interested in Forcelle Italia forks, the full address of Storz Performance is 1362 Tower Square, #2, Ventura, CA 93003. The phone manner is (805) 654-8816.

Calipers — front or back?

For a while now, a question has been baffling me. I own a 1972 Kawasaki 750 H2, and my bike comes with a single disc brake with the caliper bolted ahead of the fork. What puzzles me is that all manufacturers today offer bikes with calipers mounted behind the forks. In fact, I have noticed many restored older bikes whose owners have turned their fork legs around, so as to have the calipers behind the forks. At first I thought this might improve handling in some way, but why, then, did roadracers such as the Kawasaki H2R have its calipers ahead of the fork? Obviously, the company was concerned with handling, and thus would not have overlooked such a thing. Please tell why this is done, because if there is some advantage to be gained by the change, I will do it to my bike, too. Mehran Zeinali Montreal, Quebec, Canada

Moving the calipers behind the fork reduces the inertia of the front fork/ wheel assembly about the steering axis. That reduces steering effort slightly on quick maneuvers, but more important, the reduction in inertia aids in avoiding front-end wobbles. Alternatively, mounting brake calipers in front of the fork aids in brake cooling, perhaps leading to longer pad life. Kawasaki probably mounted the calipers in front on the H2R with brake performance in mind; in any case, you 'll find few riders or tuners of H2Rs who consider that motorcycle a paradigm of good handling.

With your H2, the effect of relocating the single caliper would be small, and any benefit that might result is probably not worth the effort involved.

Longest-lasting motocrosser

I am 13 years old and looking for a motocross bike. My father suggests an 80 or a 125. What I need to know is which lasts longer: an 80cc watercooled or air-cooled? Is this true of 125s as well? Sean Berry Brownsville, Texas

In our experience, liquid-cooled versions of motocrossers have invariably had greater piston life than did the aircooled models that preceded them.

This seems to hold true regardless of displacement, and can probably be attributed to liquid-cooled engines' lower piston and ring temperatures, and their closer control of the pistonto-c ylinder clearances during normal running.

Rotor floater

I have read with interest about disc-brake rotor warpage problems on Suzuki GS1 100s. Why not float the rotors and solve the problem? This operation doesn’t require that much skill.

This is how I floated the rotors on my 1 100. I bought some new Allen bolts to replace the stock bolts that hold the rotors to the wheel; these new bolts had an unthreaded section as thick as the rotors. Then I bought some thin-wall steel tubing that was a close slip-fit over the bolts, and cut it into sections 1/16-inch thicker than the rotors. Finally, I drilled the mounting holes in the rotors larger until they would accept the tubing. Then it was simply a matter of bolting the rotors back on the wheels with the tubing in place. This allows the rotor to float, making rotor trueness less critical. It worked perfectly on my 1 100EZ. Elmer McCullah Coos Bay, Oregon

Yours is certainly a creative solution to brake-warpage problems, but it should only be attempted by those very sure of their mechanical knowledge.

It's essential, for instance, to make the spacers from tubing sufficiently thick to spread the bolt load; otherwise, torquing the bolts down may distort the tubing into the aluminum of the wheel. That's ont y one of several problems that might occur with this modification. Fortunately, you seem to have avoided any of these, and we salute your energy and ingenuity.

Heavy-duty flasher

Here’s a tip for Gold Wing owners who have so loaded their Wings with electrical accessories that their turn signals flash slowly or not at all while idling at intersections: My Wings have all had this problem, and it can be solved by installing a two-terminal heavy-duty flasher from Nationwise intended for use on Japanese cars. It works independently of load and its rate is not so variable with voltage. Check your turn signals more frequently if you do this; it will continue to flash with burned-out bulbs. Aubrey Nabers Marietta, Georgia

Carb overflows

As a 1 3-year-old owner of a Yamaha enduro 125, I’d like to ask what the gas overflows on the carburetor are for. A friend said his YZ100 only had gas run out of its overflows when it flipped, but mine makes a constant habit of it. I know the rubber in the petcock is worn down and I ordered another. Should that cure it? If not, what would? Jeff Johnston Flesherton, Ontario, Canada

Those “overflow " lines are actually vent lines; they connect the float bowl to the atmosphere, ensuring that normal pressure is always maintained above the gas in the float bowl.

Your problem comes because the level of gas in the float bowl is out of control. Repairing the petcock will prevent gas from running out the vent lines when the petcock is in the Off position, but you 'll still have the problem when the petcock is on. That's because the float valve on your carburetor isn't sealing completely; it's supposed to shut off the gasoline flow into the carb when the gas in the float bowl reaches a certain height. Cleaning the float bowl of any dirt or grit that could be blocking the float valve, or replacing the float valve if it's defective, should stop your overflow problems. E3