[DIY small classroom]Precautions for starting a long-term abandoned vehicle


When there is a chance to get a motorcycle that has not been started for many years, in order to confirm the content of the renovation, the first thing to do is to determine whether the engine can be started.

However, before connecting the battery and pressing the start button, some preparations are absolutely necessary. Although it is just a few small actions, it is very important for engines without oil film protection.

Never believe the saying “you can ride normally a few years ago”


When restarting a motorcycle that has not been riding on one side for a long time, remember to spray lubricating oil into the cylinder that has no oil film protection. Even if the cylinder is rusty, as long as it is not too serious, you can usually start the engine by using lubricating spray and manually rotating the crankshaft.

Because the inspection or insurance has just expired, someone asks to help repair a motorcycle that hasn’t been ridden in years, or is asked, “This bike is free for you. Would you like to take over?” For the rider of the car, he should feel very lucky!

Park in the open and cover the motorcycle cover or park the car in the garage. Although the parking environment will cause completely different damage to the motorcycle, the key to resurrecting a motorcycle that has not been riding for a long time is the engine state .

When the piston is worn or the crankshaft is damaged or other serious damages, even if you are mentally prepared to know that the motorcycle is going to be overhauled, you will usually be confused when you hear “It was possible to ride normally before”.

There is no abnormal sound, no white smoke, normal riding, etc., which are usually added to the original owner’s own subjectiveness. Therefore, when making judgments, avoid accepting what others say.

After switching to a brand new battery and pressing the start button, I found that the car was in worse condition than I thought, so I have heard instances of frustration. In order to avoid an empty game, first check whether the crankshaft can rotate smoothly.


• Be careful when you want to resurrect a motorcycle that has not been started for a long time.
• Don’t try to start the motorcycle by connecting the battery directly as soon as you get it.

Depending on the storage condition of the motorcycle, sometimes the inside of the engine may already be rusty


The farther away from the oil pump, there may be a delay from when the engine is started to when the oil pressure is delivered. If there is a height difference, the problem will be more serious. If it is a vertical engine, it needs to be fully oiled near the camshaft. The photo uses SUPER ZOIL spray that can be used as oil when the engine is assembled.

Usually, you may think that even if the engine has not been started for several years, the inside of the engine will still be protected by the oil film, but in fact, the case of being corroded by moisture in the air is not uncommon.

Even if the engine of a normal motorcycle is disassembled, sometimes red rust has appeared on the surface of the cylinder liner. This degree of rust can be regarded as slight rust on the surface of the cylinder liner. As long as some rust is removed by pressing the piston ring, the engine will usually operate normally; however, if the rust is severe, the piston may even become stuck.

The reason for the rust inside the cylinder is not only the extreme condition of being soaked in water, even if it has never been soaked in water, as long as it is parked in a high temperature environment, moisture will be generated inside the crankcase. For a four-cylinder engine model, as long as the intake and exhaust valves of a certain cylinder are open, it may cause moisture inside the cylinder.

Therefore, if you start the motor directly if you are cold, it may cause friction in the rusty area, and may also damage the internal parts of the engine without oil film protection. Therefore, before the oil pump sends the oil to other parts for lubrication, it is necessary to apply some oil on all moving parts.


• One of the intake and exhaust valves of a four-cylinder engine may be open.
• Even if the motorcycle is parked indoors, the cylinder may rust.

Lubricate the cylinder and camshaft with oil and then rotate the crankshaft


Before starting the motor, you can put the ratchet plate on the bottom of the crankshaft and turn it by hand to determine if the piston is stuck. If it feels like something is stuck, it means that a certain part of the engine may have rusted.

When you want to check the engine where the cylinder may have been corroded, and the oil on the rotating part may have been dried up long ago, the spark plug hole, camshaft, rocker arm, etc., just take off the outer cover, and the oil may be within reach. Anything that will drip onto the top of the engine needs to be sprayed with oil or lubricating spray first. If it is a spray-type engine oil, use a spray that is suitable for use when assembling the engine and has higher pressure resistance than the anti-rust lubricant.

After the oil has penetrated, you will slowly turn the glove on the bottom of the crankshaft by hand. If the crankshaft cannot rotate normally, it may be that the piston and cylinder liner are rusted and stuck, or the inside of the engine is damaged. You must be clear at this time Realize that the motorcycle must be disassembled for inspection and maintenance.

On the other hand, if the crankshaft can rotate smoothly, then the first stage will pass smoothly. Then do not install the spark plug starter motor to rotate the crankshaft. If it is determined that the speed is faster than the manual speed and can rotate smoothly, use the pressure test Meter to measure compression pressure.

If it is a four-cylinder engine model, comparing the compression pressure of each cylinder can give a sense of the current status of the motorcycle. For example, even if there is only a little rust on the intake and exhaust valves, it will cause the tightness of the valve seat to deteriorate, and the compression pressure will be lower than other cylinders.

If there is not much difference in compression pressure between cylinders, a spark plug can be installed for testing. But if the motorcycle has not been ridden for a long time, sometimes it is necessary to clean the carburetor or disassemble the parts for maintenance.

As mentioned above, as long as you know what preparatory work needs to be done in order to avoid engine damage, you can play a great role in getting an old car that has not been started for a long time.


If there is no strange feeling in manual rotation, please unplug the spark plug and start the motor to let the oil reach every corner of the engine, and then perform the compression pressure test.

If the actual measured value of each cylinder is greatly different, the tightness of the piston ring and the intake and exhaust valves can be judged. If the piston ring gets stuck due to moisture inside the cylinder, the compression cannot be maintained and the compression pressure drops.


If the carburetor is not corroded, check the spark of the spark plug, and then install the cylinder head to confirm whether it can start the engine.

Whether the carburetor is blocked, whether the spark plug can produce sparks, whether the cylinders and cams are rusty, if you directly start the engine without first confirming these conditions, it will be useless.


• Directly lubricate the spark plug hole and camshaft
• Use a club or ratchet wrench to turn the crankshaft
• Measure compression pressure

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Information provided by “Webike magazine”
“Webike Taiwan” editorial department compiled

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