QuestionMark,
I recently purchased a 1997 Kawasaki Vulcan 750 from a dealer. I've only had it about 3 weeks, and it has been in the shop for about 2 of those weeks. I am just learning how to ride a motorcycle. The first night I had it, my boyfriend was teaching me the basics. I was going very slow learning how to balance, use the controls and just getting a feel for the bike. I did this for about an hour and a half or so. I took it around the block twice, and then it just died. The headlight went out and the ignition wouldn't turn over anymore. I charged the battery, but the headlight never came back on. I ended up replacing the battery, the bulb and checked all the fuses and it still didn't work, so I took it in to be fixed. They didn't know what was wrong with it, but got it working again after a few days. When I asked them what was wrong, they said they didn't know, but it's working now. I asked what happens when it happens again, and they just said it shouldn't.
So, I got my bike back and was out for my second lesson Friday night. I was just doing figure 8's in a parking lot and didn't leave 1st gear. After about 15 minutes the bike died again. Headlight went out and battery seemed to die. Somehow, we got it started. My boyfriend took it around the block, getting it into 4th gear and then brought it back. I continued to do some more turns in 1st gear and was about to take it on the road when it just died again. Both the headlight and battery; the ignition doesn't turn over. I had to jump the battery and rode the bike home about 2 miles. Once I pulled it in my driveway, it stopped working again. The shop had to come load it in a truck and take it away to be fixed again. This is supposed to be a Kawasaki dealership, but my faith in their abilities just isn't there. Do you have any idea what the problem could be. I was figuring that by driving it slowly for an ample amount of time might be draining the battery. If that's the case, that needs to be fixed anyhow, because if I get stuck in traffic, I'm screwed.
Thanks So much for your help! I really hope that this can be figured out.
AnswerHi Jody,
Riding slowly is not an issue with the charging system. If the charging system is in good condition it will work at low speeds/RPM.
I have a 1987 Honda Magna VF700C in my shop with a similar porblem. The owner sprays WD-40 over the entire MC prior to winter storage as a protective barrier. So far, I have found WD-40 in many electrical multi-connectors and control switches. I began the process of separating, inspecting and cleaning connectors late Sunday night.
I suspect a correded electrical connector or a defective wire in the wiring harness to be the source of the problem.
Electrical diagnosis can be frustrating and time consuming. The Kaw dealership may not have much patience with such a problem when they could be making money on other work.
Does the problem occur when the handlebars are turned? This may indicate a broken wire of other electrical short within the wiring. Slack in the wiring around the steering stem (neck) is pulled tight when the bars are turned side to side. Check for wire chaffing, broken or loose wiring, or other defects. Check for a loose connector. You might be surprized with a simple fix.
Check all electrical connectors for corrosion. Connectors must be clean and tightly connected to ensure low resistance and good conductivity.
Use dielectric grease on all connectors to prevent corrosion and water shorting.
Visit the following websites for more information:
www.vroc.com
http://forum.motorcycle-usa.com
www.dansmc.com
Send me your email address as requested. I'll return several tech files that will help you or someone other diagnose the problem. Standing by...
Respectfully,
Mark Shively
(sample tech file)
Charging System
The charging system consists of the alternator (rotor/stator), rectifier, voltage regulator and the battery. Problems with the charging system of these older bikes is rare in bikes of 350cc and less, moderate in bikes from 500-650cc and very common in bikes of 750cc and over. It will require a manual to do a good job in this area and if you don't have one anyway, get one(Clymer is good). Here is a breakdown of what the parts do:
• alternator: produces an alternating current by passing a moving magnetic field (rotor) through a nonmoving or static (stator) winding of wire. Gasoline is thus converted from a chemical energy to a mechanical energy (within the engine) to an electric energy (within the alternator). This energy is then sent to the rectifier.
• rectifier: converts alternating current (AC) to direct current (DC). Early rectifiers simply took half of the energy (single wave), and sent it to the battery. Since alternating current travels in both directions, the early rectifiers simply grabbed the energy going in one direction and set it on. Later rectifiers use a diode group to grab both directions (full wave) of current and combine them into one direction and sent this on. Later rectifiers were much more efficient but more prone to failure.
• voltage regulator: governs the amount of current coming from the alternator and limits it to about 14-15 volt. This is usually combined with the rectifier to make one piece of hardware. If too much current is generated, the regulator sends it to the ground or frame.
• battery: stores energy and is the main place to dispense energy as needed, to plugs and lights.
A sign of a bad charging system is when the headlight blinks or strobes at idle or when there is a marked increase in headlight intensity when you gun the motor. All bikes show some increase in headlight intensity with higher RPMs but if it goes from dim to bright, it is probably the charging system.
I will tell you in advance that finding why your battery does not charge is a hard thing to do! This is the procedure I follow to try and solve this problem.
1. Make sure the battery is good! Use a volt/ohm meter to see if it is providing near 12 volts. If it reads 10 volts or less, replace it. If it can hardly crank over the engine, replace it. Motorcycle batteries are not real good providers. They can go bad even if you take real good care of them. The small thin lead plates within are not as vigorous as a car battery ones and can be damaged easily.
2. Using your manual, read on how to connect your volt/ohm meter up to your bikes alternator. First check if there is an electrical leak in the wiring of your stator. The insulation of the miles of coiled copper wire can deteriorate and cause the wire to short and thus not provide the extended length of wire needed to pick up the energy from the magnetic field. If a short is detected, it must be replaced ($ ouch).
3. Start the bike and using your volt/ohm meter test the output of the alternator. It must be within the specs of your manual. In the 750cc, the alternator portion of the engine is low and sticks out, just waiting to be smacked when the bike goes down. If your bike has been dumped or impact has occurred to this portion of the engine, you may lose your charging power. The rotor is a magnet and can lose power with an impact.
4. Using your manual, read on how to connect your volt/ohm meter to the rectifier. With the bike running, check its voltage output. It should be within specs (14-15 volts). Now here is a problem, the rectifier converts AC into DC and this conversion requires that some of the electrical energy be converted into heat energy. You can locate the rectifier because it has heat dissipating fins located near it. Unfortunately this heat can cause a failure in the unit which can not be detected except under load (blasting down the road) conditions. So..... the rectifier may read good at idle or high RPMs in the garage but it fails on the road! Many shops will swap rectifiers if they are suspect and test ride to see the result. For us home mechanics this is not possible!
5. I have found that the voltage regulator is rarely at fault. But you can still test it by following the method outlined in the manual. The test consists of using two batteries in series and a variable resistor. In effect you try to put over 14 volts across it and see if it stops this too high voltage.
