Service

SERVICE

Foul play

I have a 1980 Kawasaki KZ1300 Six with 14,000 miles on it. Four years ago it began fouling sparkplugs. The frequency was once every three or four months for about two years, but it gradually got to where it would run great only for a few days after I would clean or replace all six plugs. Last year, the largest Kawasaki dealer in our area cleaned and synchronized the carbs, put the bike on their diagnostic machines and checked the compression. It ran great on the way home, then I parked it for about two hours. Once I started it back up, though, it wasn’t running on all cylinders. When I rode it back to the dealer the next morning, it actually ran fairly well, and they told me they couldn’t find a problem. They suggested I replace the fuelvalve solenoid, which I did-at a cost of $140-but the bike still ran poorly and in fact has gotten even worse. Now it runs so bad I can’t even get it out of the garage. Any input you can offer would be greatly appreciated.

Robert Whitfield Cleveland, Ohio

Stop chasing fuel-system problems and start looking into the ignition system: It sounds as though your Kawasaki is fouling sparkplugs not because too much fuel is reaching the cylinders but because it is producing insufficient spark voltage.

The KZ1300 uses a solid-state (no > breaker points) ignition system with three separate coils (each coil fires two cylinders); it's unlikely, then, that all three coils have failed simultaneously. The problem is more likely to reside in a single component that affects the firing of all six sparkplugs, such as the main igniter unit or the resistor in the ignition system 's power-supply line. To check these components, buy or borrow an ohmmeter and a Kawasaki KZI300 shop manual, then follow the manual's detailed instructions for testing the 1C igniter and the ignition resistor. There are numerous checks that must be performed, but this procedure is relatively easy if you work with the manual, which includes enough drawings, diagrams and photographs to make the troubleshooting process easier to understand.

Stiff shifter

I’m very happy with my 1983 Honda Nighthawk 650 except for one problem: After the engine warms up, the transmission is hard to shift from first to second gear. The shifting is smooth and easy when the bike is first started in the morning, but gets hard after the engine is warm. I’ve gone through the clutch plates and they’re fine. I’ve also drained the clutch’s hydraulic actuation system, added new fluid and bled out all the air, but the problem remains. I’ve even tried switching engine oils, which seemed to eliminate the problem for a while, but the hard shifting eventually returned. Why is this happening and what can be done about it?

Greg Hendricks Cincinnati, Ohio

In all probability, the second-gear shift fork in your Nighthawk's transmission is scored and/or slightlv bent. It’s practically impossible to track the source of this damage on a 10-yearold bike, but it's likely that aggressive, full-throttle power shifts played a key role somewhere along the line.

When the engine is cold, the lubricating oil is thick enough and has sufficient film strength to minimize metal-to-metal contact between the scored (rough and gouged) surfaces of the fork and its mating groove in the gear it must slide back and forth. Thus, shifting is smooth and easy. But the oil thins out when it heats up, thereby reducing its film strength enough to allow the higher areas of the scored fork to make metal-to-metal contact with the sides of the groove. This contact causes considerable friction between the fork and the spinning gear, making shifting noticeably more difficult.

Changing the oil can bring about a temporary improvement in shifting ease, but the problem will not go away—indeed, it will gradually get worse—until the damaged shift fork is replaced.

Filter fashions

I own a 1987 H-D Sportster 883. I have found that a Fram PH1870A spin-on oil filter will fit my bike in place of the factory filter. Not only is the Fram less expensive and easier to obtain if you don’t live near a Harley dealer, but it also is larger and matches, in color, my sparkplug wires. Will this filter harm the engine?

Vincent J. Valdes Lemont, Illinois

As long as the filter is a bypass-type (which the Fram model in question is), its use will not affect your 883 ’s engine in any way—except for earning a few added style points.

Flying on instruments

I’m having a problem with the speedometer on my 1985 BMW K100RS. About half the time, it won’t operate until after I give it a good whack with my fist (I do have a degree in Mechanical Engineering). There is no pattern as to when it fails except that it usually happens at highway speeds as opposed to riding around town. I’ve cleaned the electrical contact on the rear wheel, but this has not solved the problem. A service technician I’ve spoken with claims he knows a modification to solve this problem that involves drilling holes into the face of the instrument panel for better ventilation, along with some electrical trickery to increase the signal strength from the sensor to the analog readout. He won’t reveal his secrets but is willing to perform them for about $100. This problem is very annoying, and I know it exists in other BMW models. Any suggestions?

Stephen M. Joern San Diego, California

Do not allow your technician friend to perform his so-called “magic ” on your instruments; the modifications he suggests are appropriate for earlier-model BMW instrument packages, hut are not suitable for your K-bike unit, which is not equipped with a special Gore-Tex seal that is necessary to keep excess moisture out of critical areas. Instead, the only sure, permanent solution for your intermittent speedometer problem is to replace the entire instrument package with an improved version.

In 1989, BMW issued a Service Information bulletin that addressed chronic K-bike instrument failures. The company allotted its dealers a 24-month period in which to call in customers who were having any such problems w ith their '85 through '88model K-bikes and swap their old instruments for new ones. If your bike was not part of this upgrade, or even if it was and this condition persists, you should contact BMW's service people in New Jersey and inform them of your problem. The phone number is 201/307-4000. Have the last seven digits of your Beemer 's serial number ready before you call.

Losing your bearings

My 1984 Honda 750 Interceptor has what sounds to me like a serious mechanical problem. At temperatures of 30 degrees and below, and at speeds of 35 mph and above, the engine or transmission emits a loud shrieking noise. This noise is persistent whether or not the engine is under load. The only remedy I’ve found is to reduce speed to below 35 mph, which causes the noise to stop. I’m thinking this is a transmission problem instead of an engine problem, but I’d appreciate any help you might be able to offer.

Alan Brokenshire

Fairbanks, Alaska

Your thinking is probably correct, for it is highly likely that the noise is emanating from the output-shaft bearing right behind the countershaft sprocket. Such a noise could occur if the bearing is excessively worn, or if it has been damaged as a result of a failed countershaft seal that has allowed dirt or chain debris to get in between the rollers and the races. The subsequent wear or damage to the bearing usually involves the creation of flat spots on the rollers or tiny dents in the races. Either condition can cause the rollers to skid and chatter at certain speeds—especially in cold temperatures, which cause the rollers to fit more loosely in the bearing-resulting in a loud, high-pitched shrieking noise.

In this case, the remedy will be rather expensive: You'll have to remove the engine and split the crankcases to replace the faulty bearing.

Spin doctor

After several torturous months of faithfully short-shifting my Honda CBR900RR in accordance with the break-in recommendations, I’m finally ready to spin The Little Motor That Could; but how much will it take? Redline on the tach is 11,000 rpm, but the owner’s manual suggests not to turn it faster than 13,000 rpm, referred to as the “red zone limit.” Any staffers there at Cycle World have experience in this area?

Alan B. Jones Fullerton, California

It’s important to understand the difference between redline rpm and maximum safe operating rpm; the two are very different.

Redline is the maximum rpm the manufacturer feels you should use when the engine is being run under power. The engine will not self-destruct if you exceed redline rpm by, say, 1000 or 1500 rpm; but doing so is generally a waste of time because once the engine-in stock tune, at least-has gotten that far past its horsepower peak, it is making progressively less and less power with every increase in rpm. It therefore will accelerate much more quickly if upshifted to the next higher gear. Matter of fact, most production streetbikes today are equipped with electronic rev-limiters that will not allow the engine to be run, under power, farther than about 500 or 750 rpm above redline.

But a rev limiter can’t prevent an engine from being revved even farther if the rider downshifts while traveling at too great a speed for the lower gear being selected. And that’s what the owner’s manual is referring to with the “red zone limit.’’ It is telling you not to allow the engine to exceed 13,000 rpm under any circumstances, even during downshifts, lest you run the risk of seriously damaging something in the engine. □