The valve clearance of a locomotive is very important, and over time, a poorly maintained engine can be seriously damaged. However, if you often go to find a professional technician to do it may be very expensive, many old drivers will adjust themselves, often play motorcycle riders, their tools are no less than the repair shop.

What is valve clearance?

The valve clearance on motorcycle and automobile engines is actually related to the clearance between the top of the valve rod and the CAM operating it.

The intake valves in the engine open to allow air and fuel to enter the cylinders, while the exhaust valves expel the burning gas. The gas heats up inside the engine, so there is a sturdy "seat" that acts as a heat sink when the valve is closed. If the valve is not completely closed at the time of ignition, and the expansion of the combustion gas pushes the piston down, the valve will be damaged, and the high pressure gas will seriously damage the valve, the seat, causing irreparable damage.

Why is valve clearance important?

If the valve clearance is set to zero, the valve can theoretically be set to be completely closed, but as the engine heats up, the parts expand; Without clearance, the valve will not close completely. This is why it is necessary to check the valve clearance while the engine is cooling.

How do I know when I need to adjust the valve clearance?

Incorrect valve clearance will result in poor driving and eventually serious damage to the motorcycle. The valve gap is too large to produce metal knocking sound, and the valve gap is too small to cause lax closure leading to air leakage. Generally speaking, when the engine is ignited, the valve bin should be adjusted when it makes a large clicking sound.

What parts are needed?

If you are lucky, when you check the valve clearance, you will find that they do not need to be adjusted. There are certain tolerances for the valve clearance, for example, on the ZX-6R G2, the intake valve clearance should be between 0.11 and 0.19mm, while the exhaust valve clearance should be between 0.22 and 0.31mm.

However, there is at least one gap that needs to be adjusted, focusing on the gap between the bucket and the gasket, because it is the most common gap in modern motorcycles, and you need to buy some gaskets. The problem is, you don't know what they are until you measure them, and unless your local dealer has them in stock, keep the motorcycle off the road for a few days. You may also need some washers. If you do need to replace the gaskets, you'll need some new engine oil to lubricate them,

What tools are needed?

It is highly recommended to do your homework before doing it, and only if you have a repair guide specific to your machine can you perform the operation procedure correctly.

A common tool for disassembling motorcycles

feeler gauge

micrometer

Torque wrench

Protective gloves

Make sure your gauge covers the dimensions you need to measure in 0.01mm increments, if you need to replace the gasket, because the camshaft bracket is very precise, you do need a torque wrench, and you also need a micrometer to measure the thickness of the removed gasket. They may have a thickness engraved on it, but there is not a clear scale on the car, but you should check them.

How to check the valve clearance on a motorcycle?

If you're lucky, some motorcycles come with hydraulic tappets that automatically set the clearance between the CAM and the valve (usually via the rocker arm), but these tappets are usually only used in low-speed engines, such as some Harley-Davidsons.

Screw and lock nut regulators tend to be found on small displacement motorcycles (such as the Honda Grom MSX-125) and only need to be adjusted with a wrench and pliers, or you can get a tool to hold the lock nut in place while turning the regulator.

This is the tool used to adjust the screw and lock nut valve clearance on Grom and previously owned service cars, although there is no room on the Honda air intake unless you remove the air box. Most motorcycles use buckets and shim, the CAM presses on the assembly, and the shim determines the thickness of the pair, which is what we will look at in this article. The bucket and gasket are then pressed down on the valve to open it.

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