rdpsychoStart it up: CPR for a dead MCrdheader

by Lee Meyer

At one time or another, most of us have experienced the problem of our favorite machine not wanting to start. Of course, this usually happens with amazingly bad timing. Let’s go over some possible routes to getting the beast up and running again.

First of all, we have to come up with the specific problem. Just saying “It doesn’t start” is way too vague to make a proper diagnosis. Let’s begin with the simple and go from there.

When you turn the key to the ‘on’ position and neither the instruments nor the oil and neutral bulbs light up, check the main fuse, the battery connections and the battery itself. If these are all fine, take a look at the ignition switch. Using the wiring diagram in the manual and an inexpensive test light, you can quickly rule the switch good or bad.

Let’s say the key is turned on, and you get plenty of lights, but nothing happens when the starter button is pressed. The engine does not turn over. When you press that button, electricity does not travel directly from it to the starter. The starter draws way too much current for those tiny button wires to handle. They would melt nearly immediately. The button operates another switch known as a relay or solenoid. The solenoid has two big wires or cables attached to it, one positive from the battery and another going to the starter. Also attached are a couple of small wires from the starter button. (Keep in mind that there are variations of this.) When the starter button is pressed the solenoid connects the large wire from the battery to the large wire from the starter motor.

Now that we know what is supposed to go on, here is how to trouble shoot it. I like to rule out starter motor problems first. There are a couple easy ways to do this, and they usually involve a few sparks&emdash;don’t freak out. Locate the solenoid by following the positive cable from the battery. Grab a screwdriver, (Insulated! See This Old Bike on next page.-editor) locate the terminals on the solenoid to which the battery and starter cables are connected and cross or jump the terminals with the screwdriver. Key on or key off, the starter should turn the engine over. If it doesn’t, the starter is either dead or not hooked up a la a loose wire on the starter. Check that next. If your starter is easily accessible, you can use some jumper cables attached to a battery to test it. Hook the positive jumper to the nut that attaches the wire from the solenoid. Then simply take the negative jumper and ground it (touch it to the engine). The engine should turn over. If it doesn’t, you have a dead starter.

If all is okay, look at the solenoid. Grab a plastic handled screwdriver and hold it firmly at the metal blade end. With the key switch in the ‘on’ position hold the starter button in with your free hand and tap or whack the solenoid a couple of times with the screwdriver. It may be stuck, and this might free it up. It also tells you that it needs to be replaced. This technique does not always work, however it is a fairly common solenoid diagnosis trick.

Now, let’s look at that little button out in the weather all by itself. The small contacts behind the button get dirty and corroded. This is a common problem that affects my own bike intermittently and annoyingly. Eventually I will deal with it. You can take the switch housing apart with a screwdriver and spray it out with contact cleaner while you work the button. Be careful of contact cleaners that harm (melt) plastics. If cleaning does not help, replace the switch.

Okay, you get lights, and the engine turns over well, but it doesn’t fire at all. This may sound goofy, but check for gas. You do not want to know how many times I have had customers get their bikes towed into the shop and get charged the minimum one hour of labor to buy a gallon of gas. They got calls from me telling them in the nicest way that gas is much cheaper if they go to the gas station themselves. If there is gas in the tank, make sure it is getting to the carbs by pulling a fuel line off the tank to check fuel flow. Use a catch can for the spilled fuel, and try to avoid the gas bath. If gas does not come out of the petcock, make sure it is set on ‘prime.’ If there is no ‘off’ setting, it is either plugged up with goo or shot or both.

If you have fuel going to the carbs, but it still won’t start, it is time to check for spark. Pull the plugs and look for signs of fouling like wet, black carbon, etc. Put the plugs in the plug caps and lay or hold the plugs against the engine head or block while cranking the engine over. Be careful holding the plugs by hand. If they do not ground well to the engine, the juice might find a better route through you. Yikes! Also, certain ignition systems can be damaged if the plug is not well grounded. You should have a strong visible and audible spark on all cylinders. Sparks on half the cylinders would indicate a coil or coil wire problem. If there is no spark at all, it’s time to chase through wiring diagrams and various connectors. Some bikes, Hondas for example, use the handlebar on-off switch to disable the ignition only. These switches can become corroded or dirty and disable the ignition when in the ‘on’ position.

There are a gazillion makes and models of bikes on the road, so I cannot cover all of the possible starting problems. Hopefully though, this column gives some ideas on how to deal with the more common problems. Dirty or corroded switches are often the culprits in a no-start and so are sticky relays and solenoids. I assumed the bike was recently in good running condition, therefore I did not go into carburetion or fuel injection…very lengthy issues.

If anyone has comments or questions please feel free to write, e-mail or whatever. I will answer or respond to all. Good luck.

-Doc

M.M.M.

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