Service
SERVICE
Len Vucci
We welcome your technical questions and comments, and will publish those we think are of interest to our readers. Because of the volume of mail received, we cannot return any personal replies. Please limit your “Service" letters to technical subjects only, and keep them as brief as possible. Send them to: “Service," CYCLE WORLD. 1499 Monrovia Ave., Newport Beach, Calif. 92663.
KAWASAKI NEEDLE
I’ve read CYCLE WORLD’S 10,000mile test on the Kawasaki KZ650 in the May, 1978 issue. I am interested in setting up my KZ650 like the one you tested, and have all the parts and equipment except the jet needles.
My local Kawasaki dealer says such a needle does not exist. Are the #559 needles Kawasaki parts, and if not, who makes them and where can I get some?
Bill Dobber Longview, Tex.
The needles are indeed manufactured by Kawasaki, but your dealer is right; the #559 needles don't exist. The error was ours—the actual needle number is 5J9. These needles are original equipment on early Zls, and should be available at most dealers. Sorry for the inconvenience.
TUBELESS CAST RIMS
Having had the unpleasant experience of having my RD400C try to swap ends at
65 mph (pinched rear tube), 1 would like to purchase a set of Goodyear Eagle G/T II tires with the bead retention safety feature.
Yamaha states that tubeless tires cannot be used on the stock cast rims, I assume because of casting porosity. Can these wheels be sealed, and the tubeless versions of these tires used? If so, how?
Ben Brandt Houston. Tex.
Phone calls to technical representatives of Yamaha, Kawasaki, and Suzuki yielded the same answer: Tubeless tires should not be used on currently-manufactured bikes equipped with cast wheels. Casting porosity and bead-retention design were given as technical reasons, and product liabilit y was cited as well. We've heard of a few riders running tubeless tires on such rims, but do not feel we can make recommendations based on such limited input. Until a definitive argument to the contrary is offered, we'd adhere to the manufacturers' recommendations, and run tube-type tires.
This does not prevent you from using
Goodyear Eagle G/ T II tires on your bike. These tires are available in both tubeless and tube-type, to satisfy the needs of most riders. With or without tubes, the G/T II tires offer the retention safety feature you desire.
ELECTROFUSION
I read your article on the Kawasaki KX125A4 (CYCLE WORLD. July, 1978) with interest. In it was mentioned the process of Electrofusion, whereby a steel liner was electrically impregnated onto the surface of the aluminum cylinder casting.
Is the steel bore in the streetand enduro-model Kawasakis done in the same manner? If not, could you tell me which models have the Electrofusion-formed liners?
AÍ Dunaway Funnellon, Fla.
The Electrofusion process is presently employed in the new-model KX125 and 250 motocrossers, the KE250 enduro, and the factory works racers. It’s expected that the next production bikes to have Electrofusion liners will be the KE125 and the dualpurpose KD125.
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Because of the increased expense of the Electrofusion-lined barrels, it'll be a while before the conventional types, especially in Multis, will be superceded. But as costs are reduced, look for an increasing number of Electrofusion barrels to come into production in the future.
IGNITION UPDATE
I am considering purchase of an aftermarket ignition system, such as the Gerex High-Energy unit, for my 1978 Kawasaki KZ650. I would like to know what advantages I would gain by using such a kit, and if this is a worthwhile investment.
Also, could you explain how the stock ignition system and pointless ignition systems work.
Doug Philbrick Hemet, Calif.
Before we make any value judgements, a few words on ignition operation.
The stock point-type system of the KZ, like most other current bikes, is basically simple. Contact-breaker points are merely on-off switches, driven by the crankshaft or cam, and control the electric current flowing through the ignition coils. The coils step up the battery's 12 volts to more than 10,000, which causes a spark to jump the gap at the spark plug.
Pointless electronic ignition systems accomplish the same thing, but the method of controlling the current through the ignition coils differs and the intensity of the spark at the plug is generally greater.
These systems may be triggered optically, using a light source and a sensor, or magnetically. In either case, the trigger assembly replaces the breaker-points unit, and thus retains the engine's original advance-curve characteristics.
Some units are self-contained, that is, all the electronics circuitry fits under the original breaker-points cover. Other units, such as the Gerex, will have an additional module (“black box”) mounted to a frame member. In most cases, the units with black-boxes are capacitive-discharge ignition (CDI) systems, and will provide a much hotter spark than the self-contained units. They're normally more expensive also.
Point-type systems, the most simple and least expensive to produce, have proven themselves quite well over their long history. But because they are mechanical, they are subject to wear and become less efficient with age. After several thousand miles, spark intensity will diminish, and/or ignition timing will vary, either of which condi(ion will result in less than optimum performance and economy.
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Solid-state (pointless) ignition systems are essentially set-and-forget. They will normally require no maintenance, and will continue to produce consistently hot sparks with no variation in ignition timing.
Additionally, the hotter spark output of electronic ignition systems, especially those of the CD1 variety, will promote more efficient combustion, resulting in better performance and fuel economy. This effect is most noticeable after the spark plugs have been in use for several thousand miles and require a higher voltage to fire. Faced. with more stringent emissions requirements, which place a heavier burden on a bike’s ignition, manufacturers are equipping more new street bikes with electronic systems as original equipment.
There is no question that pointless electronic ignitions are superior to breakerpoints setups. But they’re also expensive— anywhere from $60-$75 for a budgetunit, up to nearly $300 for the luxo versions. For your money you 'll receive longer spark-plug life, freedom from ignition maintenance hassles, and a slight edge in performance and economy. Whether the initial outlay is worth these results is dependent upon your type of riding, annual mileage, duration of ownership, and whether or not you do your own maintenance.
We've installed units from several manufacturers on test bikes, all with excellent results. We can’t quote a dol/ars-and-cents comparison of operating costs between a stock bike and one with an ignition coversion, mainly because we haven’t tried.
KAWASAKI OIL LEVEL
I own a 1978 Kawasaki KZ 1000. and I'm not sure of the right way to check the oil level. My dealer told me to disregard the oil sight window in the side of the crankcase, and simply replace the oil, after draining, with 3.9 quarts, the amount recommended by Kawasaki. When I’ve done that, the oil completely covers the window, and it appears as though the engine is overfilled. Also, this method does not give me any indication if the engine is low on oil between changes.
I’ve checked with several other dealers in my area, but they’ve all given me different answers. What is the right way?
Michael Laroche Warren, R.I.
According to the Kawasaki Motorcycle Service Manual, the sight window is the definitive measuring tool. To check the oil level, place the bike on the centerstand on level ground. The oil level, viewed through the sight window, should fall between the minimum and maximum marks. Oil should be added if the level is low, and drained if too high.
If the oil and filter are drained and replaced, it is first necessary to run the engine for 30 seconds or so to allow the filter to fill. The engine should then be shut off, and allowed another half-minute before the level is checked. If the recommended 3.9 qt. is added, but the engine is not run before the level is checked, the window will indeed be covered as if there were an excessive amount of oil in the crankcase.
The procedure is simple—just make sure the bike is level to ensure an accurate measurement.
RD400 MISFIRE
I own a Yamaha RD400C which has a big problem. After a few miles of in-town riding, any attempts to crank up to 7500 rpm causes sputters, pops and misfires. Eventually, the problem clears up, but only after many miles of throttle work and coaxing. Eve checked my timing, and it’s right on, and my plugs are a tan color. The only modification is a set of K&N air filters with #210 main jets.
Any suggestions on how to cure the problem?
J. M. Coutlee Elmendorf AFG, Ark.
From the limited information you've provided, we can offer a possible cause and cure. It seems to us that the engine is running too rich on the top end because of an excessively large main jet. Because of the increased flow capacity of the K&N filter, you were correct in installing larger mains. But #210 jets are just too big for this application. The stock main jets are #115— we 'd switch to a set of # 125 or # 130jets as a starting point, if the engine detonates under full-throttle high-rpm operation, richer larger jets are in order. If it fourstrokes and sputters under the same conditions, you'll have to go smaller in main jet size.
While you're at it, a wise move would be to raise the needles a notch or two to enrichen the midrange. Most in-town riding utilizes the needle jet and metering, so their operation is also important.
For additional tips on tuning, refer to the carburetor articles in the December, 1977 and January, 1978 issues of CYCLE WORLD.
