Cycle World Service
CYCLE WORLD SERVICE
Wobble fix
In the March, 1984, Service column, Chris Hanley described a problem with a deceleration wobble on his CB1100F. I purchased a CB1100F last year also, and after about four months, the same problem developed with my bike.
After experimenting with the same things as Mr. Hanley, I had the dealer torque the steering head bearings to the maximum value (87 ft.lb.). The result was slightly heavy steering at first, but it quickly loosened up. The wobble disappeared however, and several months later the bike still doesn’t exhibit the slightest wobble.
I also tried adding a steering damper. The damper gave the bike a much more secure feel at high speeds without sacrificing much steering lightness at low speeds. I also had a damper on a Suzuki GS1000, and I am convinced that most larger bikes can benefit from a steering damper if they are ridden hard.
Lars Pedersen
Morro Bay, Calif.
Torquing steering head bearings to this extent makes them act like friction dampers, and several readers reported this as a cure to CB1100F wobbles. It’s a cure that can only be used on bikes with tapered roller bearings in the steering head, because the high loads involved would dent the races of ball-type bearings.
Adding a hydraulic steering damper will have a similar effect, and could be applied to any motorcycle.
It’s not a cure-all, however.
It will reduce front end wobble, but won’t do much for high speed cornering weave, the type where the bike feels like it has a hinge under the seat.
4-into-2 exhausts
Why do motorcycle manufacturers continue to use 4into-2 exhaust systems when a 4-into-l seems to have all the advantages? Isn’t it an accepted fact that a 4-into-l system is lighter, more power efficient, cheaper (fewer parts), and quieter. (Quieter because with a 4-into-2 system, each side gets only half of the exhaust pulses and these lower rates are louder to everyone’s ears. Also there are two sources of sound instead of one with the 4-into-l system.)
Lee Swindler
Rapid City, S.D.
There’re two reasons for 4into-2 systems predominating: First,styling. Motorcycle buyers have voted with their dollars for four cylinder models with symmetrical exhausts. Second, muffler efficiency is directly related to muffler volume; the more volume, the less back pressure for a given noise level. A cross-over tube generally con nects the mufflers of 4-into-2 systems, allowing each exhaust pulse access to both mufflers. So 4-into-2 systems can have two svelte mufflers that don't interfere with ground clearance when
compared with the large single muffler that would be required with the 4-into1 system at a given noise and flow resistance level.
Sportster belt drive source
In your February issue you told Theodore W. Polonus that it would be hard to adapt his Sportster to a primary belt drive. I wish to pass along some information that might interest Theodore. Primo Products, Inc. (6416 S. Western Ave., Whittier, Calif. 90602) has a primary belt conversion for Sportsters designed to run wet and be able to retain the stock primary cover.
I haven't got one yet, but people I know who have the belt drive claim some reduction in vibration but mostly a reduction in drive train lash, quieter operation, and quieter (less clunking) shifts.
Winfield G. Lowery
Houlton, Maine
We’ve also learned that Phase 3 makes a Sportster belt primary kit, to be run dry. (The lower oil passage between gearbox and primary case is plugged.) And Mert Lawwill only needs enough orders to justify tooling up for the XR750 belt primary-clutch basket he’s designed. If any Sportster owners have tried the belt primary conversion, we’d like to hear about their experiences.
Suzuki 1100 hop-up
A s an owner of a 1980 GSI 100E, I would like to know some recommended engine modifications for increased performance and horsepower, beyond 4into-l pipes and beefed-up clutch.
Chris Meadows
Pennsville, N.J.
One of our staff members who races GS1100s says that the best results with the big Suzuki engine can be obtained by making it bigger. He recommends installation of the Yoshimura 1140 piston kit with no other modifications. Yoshimura’s address is 4555 Carter Court, Chino, Calif. 91710, and their phone is (714) 628-4722.
More on Ducati clutches
Contrary to your advice in the Service column to Scott Bury with his lurching Ducati, there is a simple fix. Many old timers who cut their teeth on British iron would routinely pull the clutch lever in and kick a stone cold engine over on compression till the clutch plates broke free. This works fine on the
Ducati, too, as it lacks primary kickstarting, and allows a lurch-free shift into first gear. If not, the clutch may be dragging. Some early Ducati Vees had machining burrs inside the clutch basket which could hang up the drive plates. Another point worth checking is that the big nut holding the clutch to the mainshaft is torqued to 80 ft.-lb. and sealed with blue Loctite. This nut has been known to back off with ominous results if not treated properly.
Ted Cais
Califon, N.J.
Honda CB360 starting
i have a 1976 Honda CB360T and it will not start very often with the electric starter, and requires the kick starter instead. Other people I’ve talked to with this model have the same problem.
When you use the electric starter it will try to start and if it does not catch on the first try, it won’t start. After that, the kick starter will usually do the job on one kick. What’s wrong with the electric starter?
Bernard Linkhaver
McKeesport, Pa.
There’s nothing wrong with the starter. The problem is a marginal charging system that fails to keep the battery fully charged. The best you can do is to make sure that all components in the electrical system are working at their peak. The battery should be full of fluid, and if it shows signs of sulfation (whitish deposits on the battery plates inside), it should be replaced. Even then, this bike will have a tendency to run the battery down during short trip, around-town use. One possible cure would be to install a headlight switch and shut off'the headlight during the day.
