Kick-Starting An Old Motorcycle
Up until the mid-seventies, most motorcycles were kick-start only, but electric start became increasingly requested by riders, and eventually became standard equipment on most street machines.
Part of owning a classic motorcycle is learning how to start your bike in as few kicks as possible. Although the techniques for kick-starting an old motorcycle are basically the same, every bike is a little different - even the same makes and models can be slightly different.
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For an engine to start, it must have compression, spark, and fuel. Engine timing (when the valves open and close in relation to piston travel) needs to be correct, and of course, nothing damaged or broken in the motor.
Know Where The Compression Stroke Is
Before turning on the ignition switch or opening the fuel valve, slowly kick on the kick-lever until you "feel" the compression stroke. This would be Top Dead Center - when the intake and exhaust valves are closed, and the #1 piston is coming up to compress the air/fuel mixture.
Remember the phases of a four-stroke internal combustion engine - intake, compression, power, exhaust. With experience, you will feel it in the kick lever, it's at the top of the kicking arc. If you're not on the compression stroke, the bike's not gonna start.
Kick the bike over two or three times with the fuel and ignition switch off. This is to get the engine primed with oil. Then turn on the fuel valve, the choke or enrichener device, and ignition switch. Twist the throttle once or twice, find the compression stroke and kick. A well-tuned motor should start in several kicks.
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Fuel on, one or two twists on the throttle, ignition on and kick. No choke or enrichener should be needed.
Try Standing Over Or Next To The Bike
Motorcycles can be started while being straddled, but that takes experience. Put the bike on the stand, balance yourself with your left foot on the left foot-peg, and kick with your right foot. This kicking angle requires less effort. For high-compression, big-displacement engines, you'll need to get more power into the kick. Try standing to the right of the bike using your left foot to kick. If you don't weigh much, it gives you better leverage to kick down with. When I was a teenager, this technique helped me to kick-start bikes that were bigger than I was.
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Gerard from Rolling Thunder Cycles suggests resting your left knee up on the seat while kicking the bike over. He explains that this places all the weight from your left side "above the action", and if the engine were to kick back you'd be more likely to be shoved upward instead of hyper-extending your right knee.
Keep The Bike In Tune
It is true that a kick-only engine is more finicky to start than an electric-start engine. If your bike has ignition points, check the gap frequently. Check the gap and look at/clean the spark plugs. Also, if your motor is modified, it's very important to find a carburetor that works well on your bike.
Back when I was riding my 1972 XLCH Sportster, other Harley riders used to mock my 40mm Mikuni (Japanese) carburetor, but it worked well. To my delight and their surprise, the bike started consistently on the 1st or 2nd kick.
Use A Lighter Grade Oil
Chances are you won't be riding your classic bike for hours in hot weather, so a 60w or 50w grade of oil won't hurt the motor and will make the bike easier to kick. I put 70w oil in my electric-start XLH Sportster, but used 50w oil in both my kick-only 1974 Triumph Trident and XLCH Sportster.
If the Bike Still Doesn't Start
If the engine spits out the exhaust-pipes while you're kicking, you're getting closer. Try holding the throttle all the way open when you kick. You may have flooded the motor. Remove a spark plug and see if it looks wet or smells like gas.
Since kickstart bikes don't use a battery for starting, it can be in pretty bad shape without you knowing. Check the connections, and the fluid level. Top off with water if necessary, and allow to stand awhile before charging. Put a small trickle charger on it overnight.
Starting a Bike with Manual Advance
Many pre-sixties motorcycles did not have automatic timing advance. Usually it was controlled by a cable from the left-hand grip to the distributor. To start a bike with a manual advance, such as an old Linkert-equipped Harley, try the following. With ignition off, turn the gas on, full choke, and retard the timer (twist left-hand grip). Give two full kicks, one click off on choke, then turn on the ignition switch. One good kick may start it. If it does, advance the distributor. Open the choke as soon as it warms up.
If it takes more than a dozen kicks to start your bike, look for another problem. Start at the spark plugs - if the plugs are wet, the motor is getting gas. To check for spark, you can either take off your points cover and see if the points are sparking, or remove one spark plug and ground it to the frame or engine. Then kick the bike slowly with the ignition switch on to see if you're getting spark.
Kick-starting an old motorcycle is part of the classic motorcycle culture. Some of these tips and techniques should help newer riders with older machines. Once starting procedures are learned, they become second-nature to you. And wear a good pair of boots - you should be anyway.