Service

SERVICE

Paul Dean

Mislead about lead

I have a 1998 Kawasaki KLR650 with 3800 miles on it. I bought the bike in Colorado Springs, Colorado (elevation 5000 feet), in May of 1999. I am an Army retiree residing on a somewhat remote island in the Philippines that is only about 150 feet above sea level. There is no pollution at all on the island and thus no unleaded fuel is available. The closest station that carries unleaded is 40 minutes away by ship/boat. Other than me purchasing a 55-gallon drum of the stuff every month and shipping it to my island, is there anything that I could do to the KLR to allow it to run leaded fuel without damaging the engine? The bike is stock except for a SuperTrapp IDS (Internal Disc System) muffler.

Chris Rea Guimaras Island, Philippines

To run leaded safely in your KLR, all you need to do is dump some of it into the fuel tank. I would suggest using at least 89 octane, but that’s about the only stipulation. In fact, racing fuels, which are commonly used in latemodel motorcycle engines, employ lead to boost their octane ratings up to the levels required for competition.

Problems can arise when the situa-

tion is reversed—when an engine designed to run on leaded fuel is fed unleaded. Lead is not only an octane booster, it also acts as a lubricant for the valve stems, valve guides and valve seats; in an engine designed to rely on such lubrication, the absence of lead in the fuel can cause quick and excessive wear in those valvetrain components.

Trouble can, however, result from the

use of leaded fuel in an engine designed for unleaded when the exhaust system involves any kind of catalytic convertor. The by-products of combustion created by the burning of the lead additives contaminate the catalytic material, quickly rendering it ineffective. Your KLR650 does not have catalysts in its exhaust system, so no problems will result from its use of leaded fuel.

Taking it to the limiter

I have a 1995 Honda Shadow ACE 1100 with 52,000 miles on the odometer. I live 25 miles from work and ride it every day. I had some straight-shot pipes installed and the carbs were jetted at the same time. For the most part the bike runs fine (it doesn’t like to start when the temperature is below 30 degrees, but neither do I) except that when I rev it real high or am trying to race someone at full throttle, it cuts out. When I let off the throttle just a little bit, it runs fine again. It acts like it is either starving for fuel or choking on it. I asked my mechanic and he said that the bike has a rev limiter on it. If this is true, is there a way to take the limiter off or work around it? Except for the pipes and a K&N air filter, the bike is pretty much stock. Troy Smiddy

Clyde, Texas

Yes, the Shadow ACE does have a rev limiter, but your engine’s inability to run properly at full throttle has nothing to do with it. The behavior you describe is a classic symptom of an excessively rich mixture at full throttle caused by main jets that are too large. When you back off the throttle just a little, the slides in the carburetors drop slightly, which also

lowers the needles in the slides down into the needle jets just far enough to begin restricting the flow of fuel, thereby leaning out the mixture.

I can’t offer any specific rejetting recommendations because I don’t know which straight-shot pipes you are using or the size of the main jets in your carbs. All I can suggest is that you replace the main jets with the next-smaller size and then check their effect on the bike ’s performance at full throttle. You might need to drop down more than one jet size before the engine performs as it should. Just be certain to get a good full-throttle plug reading every time you change jets to ensure that the mixture is not lean enough to cause engine damage.

That’s what friends are for

I’ve got an unusual problem with my 2000 Harley-Davidson Dyna Low Rider. I loaned the bike to a friend of a friend, a guy who claims to be an experienced Harley mechanic. He said he wanted to take some measurements of the new disc-brake system that Harley is now using on all the 2000 models to see if he could adapt it to a custom he’s building. He promised he wouldn’t ride the bike, but to make sure he couldn’t, I didn’t

leave him the ignition key. When I got the bike back, the odometer had the same mileage as when I left it with him. But ever since then, the rear brake pedal feels mushy, and brake fluid keeps seeping from the seam in the rear caliper. This guy claims he never messed with the caliper and refuses to fix it. I don’t want to take the bike to the Harley dealer for fear that they’ll void my warranty just because I allowed someone to cause a problem with the brake. Got any ideas about what I should do? Frank Penn

Athens, Georgia

Certain Harley dealers are known to be mercenary, but I doubt that any of them would void your entire warranty just because someone tampered with the rear brake. They might make you pay for repairs to the affected components, but canceling your warranty would be an unreasonable act. If that were to happen, a phone call or a letter to Harley’s customer service department in Milwaukee would be in order.

Besides, the problem with your rear brake doesn’t seem all that serious. The caliper is a two-piece unit with two hydraulically activated pistons in each half. The assembly is held together with

three bolts, and fluid travels between the caliper halves through two small orifices that are sealed with O-rings. Apparently, your friend ’s friend took the caliper apart and, when reassembling it, either failed to tighten the bolts properly or damaged-or perhaps even omitted altogether-one or both of the O-rings. And in the process, he permitted air to enter the system. The solution is simple: Remove the caliper, undo the three bolts and install new Orings. Reassemble the caliper, tightening the three bolts to 28-38 foot-pounds of torque, then reinstall the caliper and bleed the rear-brake system. A firm rearbrake pedal should reappear and the weepy caliper should be gone. Then, all you ’ll need to do is remember not to loan your bike to strangers.

To V or not to V

I’m trying to replace the 110/90H16 and 140/90H15 Dunlop Elite 491 tires on my Great Old Machine, a 1986 Yamaha 700 Fazer. Ed like to use V-rated tires, but I can only find H-rated tires in the Fazer’s original sizes. Would it be safe to use a 120/80V16 in the front and a 150/90V15 on the rear? Eve asked several mechanics if these would be a good fit, and they all say, “I’m not sure.” Help! I need new rubber! Mark Verry

Wernersville, Pennsylvania

You have a couple of options here. First, Avon sells a V-rated front tire in your Fazer’s original size—a 110/90VI6 AM20 Super Venom-and recommends mating it with an H-rated 140/90H15 AM21 Roadrunner. Installing a V-rated 150/80V15 on the rear would be a safe choice, but its increased circumference would also effectively raise your final gearing by as much as 4 percent, which is roughly equivalent to bolting on a two-toothsmaller rear-wheel sprocket. That would lower engine rpm at any given road speed and take some of the snap out of the Fazer ’s acceleration.

But your worries about speed ratings may be for naught. An H rating means a tire is capable of surviving sustained speeds of 130 mph at its maximum load rating, while a V-rated tire ups that limit to 149 mph. Your Fazer’s absolute top speed, as measured by radar gun in our May, 1986, road test, is only 134 mph. So, unless you load your Fazer to or beyond its maximum GVWR (Gross Vehicle Weight Rating)—which is 980 pounds with the original-equipment tires-and run it as fast as it will go for miles on end, the

speed rating of the tires is not relevant to your riding needs.

True grip

I ride a ’92 Ducati 907 i.e. that has about 16,000 miles on it. Fately, every time I apply the front brakes, I feel a noticeable pulsing through the brake lever. The harder I brake, the more severe the pulsing. The bike has done this since new, but not as dramatically as in the last 1000 miles or so. The bike has never been dropped or in an accident. The runout on both front rotors is .005-inch. The thickness of one rotor is .160-inch, plus or minus .003-inch, and the other is .155inch, also plus or minus .003-inch. The brake pads are new, as are the tires, which were just balanced, and the brake lines are braided stainless steel. Thanks for any input. M_FITZGIBB0NS

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Your 907 needs new brake rotors. According to Ducati ’s tech people, runout exceeding .003-inch is excessive and reason enough in itself to warrant rotor replacement. On top of that, the minimum recommended rotor thickness is .177-inch, a standard your Duck’s discs fail to meet by as much as .025-inch.

Before you bolt up those new rotors, however, use your dial indicator to check the rotor-mounting bosses on the wheel for the trueness of their surfaces. Even one measly thousandth of runout in that area will be amplified to three or four thousandths out at the extremities of the rotor. Make sure those bosses are true, even if you have to remove the wheel and have the bosses remachined.

It’s those long winters

I have a 1997 Suzuki TF1000S. Does it hurt an engine to rev it up to the rev limit in neutral or in gear while doing a burnout? I’m talking about holding the throttle wide-open and allowing the rpm to bounce off the rev limiter like a dragster that has its rpm limit set for an optimum launch. I have done this, especially when showing off. TL Steve

Kitchener, Ontario, Canada

The purpose of a rev limiter is to keep an engine from revving high enough to inflict damage on itself Before the invention of rev limiters a couple of decades ago, engines could keep revving higher and higher until something either broke or stopped functioning properly. The aftermath ranged from simple valve float that caused no serious problems to catastrophic failures such as bent valves, broken pistons and snapped connecting rods.

Different rev limiters work in different ways. Some retard the ignition advance so dramatically that the engine cannot spin any faster; others kill the spark to some or all of the plugs; and many fuelinjected engines limit rpm by cutting off the supply of gasoline to the injectors.

Done infrequently and for a length of time that does not exceed a second or two, your showoff practice of letting the rpm bounce off the rev limiter should not damage the engine. But were it my TL1000S, I wouldn’t do it at all.

VFR=vibe-free riding

Regarding your response to J.C. De Hoyos’ Service letter (“Intercepting the vibes,” March, 2000), I have a ’98 VFR Interceptor that used to vibrate in the 5500-7600-rpm range. The vibration was significantly reduced by synchronizing the injectors, a 15to 20-minute job that results in a major improvement.

I would recommend it for any 1998 and newer VFR. Albert.Oakley

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Inform J.C. De Hoyos to check the bottom exhaust-system bolts on his ’98 VFR800 Interceptor before he modifies everything else. netters2

Posted on America Online

Thanks for the tips. 1 'm sure that Mr. De Hoyos and other 1998-2000 VFR owners greatly appreciate your feedback. □

Got a mechanical or technical problem with your favorite ride? Can't seem to find workable solutions in your area? Maybe we can help. If you think we can, either: 1) Mail your inquiry, along with your full name, address and phone number, to Cycle World Service, 1499 Mon rovia Ave., Newport Beach, CA 92663; 2) fax it to Paul Dean at 949/631-0651; or 3) e-mail it to CWlDean@aol.com. Don't write a 10-page essay, but do include enough information about the problem to permit a reasonable diagnosis. And please understand that due to the volume of inquiries we receive, we can't guarantee a reply to every question.