Service
Service
EVERYBODY JUMP CARB UNLOADING CHECK YOUR HEAD ASK KEVIN
RAY NIERLICH
WAITING TO GET JUMPED
Q: I accidentally left my key on all night on my 2009 Harley-Davidson Road Glide, and now my battery is completely dead. Is it okay to jump it from my Dodge pickup or another vehicle?
NICK STEIN CYCLEWORLD.COM
A: It is always better to recharge a battery slowly, especially if it has been drained completely dead. If time or circumstance doesn’t allow, then jumping from another vehicle is a viable option. It really doesn’t matter what the jumping vehicle is; the most important thing is to not treat the process casually.
Connect the positive (red) terminal of the dead battery to the positive terminal of the good battery. On the negative (black) side of the process, the most important thing is to make your last connection cable to a good chassis/engine ground away from the battery. Why? Discharged and charging lead acid batteries can produce hydrogen, which is explosive. You may have heard of the Hindenburg. Many lead-acid batteries are sealed and the gas should escape, but the safest thing is to connect away from the dead battery.
If time allows, the best thing you can do is connect the jumper cables as described with ignition off on both vehicles and wait awhile before starting the jumping vehicle, and then wait awhile to start the jumped bike. Keys off, the two batteries will naturally attempt to even out the voltage difference (charging the dead battery) more gradually than if you were to immediately try to jumpstart the dead motorcycle. This extra time allows the dead battery to get at least some level of charge in it before expecting it to operate on its own again. If your truck battery is in good condition, it will not go dead charging the much smaller motorcycle battery.
Your bike’s electronics (alternators, ECUs, electronic ignitions, etc.) are designed to operate in a voltage range of typically about 9 to 16 volts DC. When you jump-start your dead bike right away, it will go from zero voltage to whatever the charging vehicle is supplying to the dead vehicle (usually 14.1 to 14.3 volts when running) in a moment. No problem here, but when the jumper cable is disconnected after starting, the reference voltage all your expensive electronics see instantly goes from 14.1 to zero, or close, depending on how impatient you have been. Then, the system sees a tremendous voltage spike once your alternator realizes it is no longer operating with a fully charged system and attempts to max out. Diodes and transistors—the key players in your motorcycle electrical system—don’t enjoy the experience, so remember patience is a virtue. Another option is to carry a compact lithium-ion jump-starter. CW staff has direct experience with the Weego Standard JS6 ($80; myweego.com), which has ample power to start any motorcycle. The same rules apply as jump-starting from another vehicle. Take your time to allow voltage to rise in the dead battery before starting.
THE ICEMAN STORETH
Q: I have a question about winterizing my carbureted Triumph motorcycles. I get different opinions from people I ask. I do use a fuel stabilizer. I fill the tank just before storage and add the stabilizer. Should I just run the bike a bit to get the fuel stabilizer down through the carbs, or should I shut the fuel supply off and run the bike until it dies thus emptying the bowls on the carbs? This would leave the carbs dry all winter. I live in Ohio and typically do not ride from December to mid-April.
RANDALL RUCKER
CYCLEWORLD.COM
A: Run the carbs empty. At least your bike has proper fuel petcocks, making this a simple task. If you must leave fuel in the carbs be sure to run it long enough for the stabilizer to be sucked through them. Using a stabilizer is way better than nothing, but sometimes vanish/corrosion problems can still occur. Minimize the air space in the fuel tank by topping off, as you are doing. If it isn’t too inconvenient, consider draining the fuel tank empty as well.
HELMET USE-BY DATE
Q: We all know about the helmet expiration standard at five years. No one has ever actually tested this. It’s all conjecture and theory. I’ve even asked Snell. Leading me to wonder where this came from. My guess is that it was some helmet manufacturer marketing or sales department, who’s just trying to sell more helmets. Who was the first person who proposed this idea, and why?
JEFF COBB BATON ROUGE, LA
A: You have but one brain, so let’s use it to think about this. Are you in grave risk if you don’t replace your helmet every five years? Probably not. To answer your basic question, we quote the Snell Foundation: “The five-year replacement recommendation is based on a consensus by both helmet manufacturers and the Snell Foundation” (read the whole statement at smf.org).
We are not aware of an aged-motorcycle-helmet impact-test study, but a bicycle-helmet study by MEA Forensic (meaforensic.com) found minimal degradation of EPS over time—based on impact performance testing it performed—using 770 bicycle helmets between two and 26 years old. So the EPS in a well-cared-for motorcycle helmet that hasn’t been exposed to chemicals or EPS-deforming impacts could offer adequate protection for more than five years. But comfort foam, straps, glues, and resins used in helmets could degrade over time—“could” being the operative word.
Helmet makers do us a service by developing new techniques and materials that make helmets lighter and more compact while offering similar protection. Yes, recommending five-year replacement may help sell more helmets, but new helmets offer tangible improvements outside of just EPS performance (removable, fitable interiors, quieter designs, improved aerodynamics, etc.), so periodic replacement is not a bad idea.
FEEDBACK LOOP
In the July 2017 printed issue Service column, a James McCracken wrote about hard starting on an ’83 Suzuki GS1100 and a '90s Honda CBR600F3 if they sit awhile. I had a ’79 CS850C for 27 years and 100,000 miles with the same problem. More than seven days sitting and it was crank, crank, crank. What I started doing was turning the petcock to “Prime” before putting on my hat, coat, and gloves. That made sure the carburetors were full of fuel and ready. Never had a hard-starting problem after that. Just remember to turn back to “Run” before starting so you don’t run out of gas somewhere down the road.
TERRY HERR CYCLEWORLD.COM
Thanks for the recommendation based on yoor impressively long experience with a relatively rare and interesting Suzuki. It can’t hurt to do as you say after long periods parked.
ASK KEVIN
VALVE CLEARANCE CHECK AND ADJUSTMENT
Q: My Suzuki S40 air-cooled engine requires checking the valves for potential adjustment every 4,500 miles. There are other motorcycles that need adjustment checks only after a much longer period of time. These mileage requirements can vary greatly depending on the make and model of the motorcycle.
Why are mileage requirements for valve adjustments so different on different motorcycles? How do the engineers decide on the valve adjustment mileage interval?
RON GLAUM
CYCLEWORLD.COM
A: Thank you for your interesting question. First of all, there must be some cold clearance in the valve train to allow for heat expansion of the valves in operation. If clearance becomes too small, valves may leak. If too big, there is valve clatter. We want that clearance to be just right.
As an engine runs, its valve train is subject to some wear of cam lobes and tappets-wear that tends to increase cold valve clearance. At the same time, so-called valve seat recession also takes place. When the valves are on theirseats, some local micro-welding of valve to seat takes place. When the valve lifts, the micro-welds are broken, creating wear particles. This loss of material causes the valve to everso-slowly seat more deeply, decreasing cold valve clearance. Valve train and seat wear can occur more quickly with use of aggressive cam profiles, which typically require stiffer springs, causing cam and tappet to wear from extra seat pressure. Same for seats, when higher rate springs shut valves harder. Ideally, the two gradual effects would pretty much cancel, resulting in constant clearance. If there’s more money in the budget to assure this desirable outcome on premium models than on lower-markup bikes, we can just chalk that up to a free market economy.
Kevin Cameron
