The torque wrench is necessary for the work that the tightening torque of the bolt and the nut is decided. Clicking!If you can use the preset type wrench to tighten until you feel the response, you can feel the quality of maintenance has been improved. However, do you know the correct way to use this preset type??
There is a proper tightening torque for any bolt or nut.
Since the camshaft is pushed by the reaction force of the valve spring, it is important to control the tightening torque of the fixing bolt of the holder that holds the cam. If the bolts are over-torqued for fear of loosening, it is easy to damage the female threads in the cylinder head. The Kawasaki Z1 series, one of the most popular out-of-print bikes in the world, has many examples of damaged female threads.
The standard tightening torque is determined by the size (thread thickness) of the bolt and nut, and there are also cases where the torque is specified for each tightening point. The type of bolts and where to use them can be found in the service manual. The flange of the exhaust pipe is warped when the muffler is repeatedly installed and removed.
When tightening screws such as bolts, nuts and screws, do you ever wonder how much force to apply??The main premise is to fix the parts, so it is out of the question to loosen them due to under-tightening, but it is also a mistake to tighten them with a lot of force just because you think it is good if they do not loosen. Over-torquing may cause damage to the female threads, and in some cases may lead to damage to the part itself.
If it is a combination of iron bolt and iron nut, it is often acceptable to over-torque to a certain extent, but if the counterpart of the iron bolt is aluminum material, for example, the cam holder bolt which is fixed to the cylinder head, care should be taken. If you apply a torque of more than 20Nm to M6 bolts, which are commonly known as bolts with a diameter of 6mm, there is a greater chance of damaging the female threads on the aluminum cylinder head. If it is the first time to install and remove a new part, it may be able to withstand it, but if it is repeatedly installed and removed, it will become fatigued, and at some point, the female threads may stick to the bolts with a "slippery" response and lick them.
In order to prevent such problems.Appropriate tightening torques are set for bolts and nuts according to their thickness.The torque is the same for all bolt nuts. Basically, the principle is to use smaller torque for thinner bolt nuts and larger torque for thicker bolt nuts. It is a matter of course, because the motorcycle manufacturer determines the strength required for each part when designing, and sets the bolt and nut accordingly. Nevertheless, if you apply a torque that far exceeds the set value, it is no wonder that the bolt is destroyed.
The torque wrench replaces the force to tighten the bolt or nut with a numerical value. In the service manual, the tightening torque of each part of the body is described, and the standard torque is specified even for the part which is not especially specified. It is up to the motorcycle user to decide which bolts and nuts to use the torque wrench on, but if you use the torque wrench to objectively check the tightness of a standard M5 or M6 size bolt, you may find that the tightness is surprisingly light. In other words.A lot of riders unknowingly work in overtorque.That's what I'm talking about.
- Point 1. Bolts and nuts have appropriate tightening torque according to their size.
- Point 2 - If you tighten the bolt and nut without being aware of it, there is a high probability of over-torquing.
Preset type torque wrench to increase the satisfaction of motorcycle tinkering
The tightening torque changes as the distance from the bolt to the grip changes. Torque wrenches are generally designed to achieve the set torque by applying force to the center of the grip and should not be held off center.
The torque wrenches are preset (pre-set) type There are several types, including beam, dial, and digital types, but the basic thing to remember is thatEvery torque wrench is a precision measuring instrumentIf you use a spanner or a screwdriver, you can throw it. It is not to say that you can throw a spanner or a screwdriver, but you need to be more careful in handling than normal hand tools because they have a built-in mechanism to measure torque.
There is a difference in the measurement method depending on the type of wrench, but the preset type is familiar to many riders and Sunday mechanics because they can set the torque by turning the grip part at the back end of the wrench, and when the torque reaches the set torque on the target bolt or nut, it will let them know with a click sound and response. This type of wrench is familiar to many riders and Sunday mechanics. If the wrench can let you know that it is at the correct torque, you will be able to ask yourself, "Will this amount of force be enough? ......?You don't have to worry about overtorquing and breaking your bike.
The tightening force to the bolt or nut changes according to the distance from the bolt to the point of force applied to the tool. Even if the force applied to the tool is the same between a short length spectacle wrench and a long type wrench, the force applied to the bolt will be different. On the other hand, the force required to obtain the same tightening force is also different between a short wrench and a long wrench. Therefore, the length of torque wrench and spectacle wrench must be the same in order to replace the 10Nm of tightening force you experienced with the torque wrench with the spectacle wrench. However, after you have experienced the tightening torque that the torque wrench tells you several times, you will be able to understand the amount of force even if the distance from the bolt to the force point changes. In order to get such knowledge, it is beneficial to use torque wrench for tightening work.
Depending on the product, torque wrenches have a range of torque that can be measured, such as 5-25Nm, 20-50Nm and 50-100Nm. If you want to do engine maintenance, you need 5-50Nm (if you want to remove and install flywheel and clutch center nut, you need more than 100Nm), and if you want to do body work, you need upper limit 100Nm. If that is the case, one wrench will not be able to cover it, so you will need several wrenches with different measurement ranges.
- Point1・There are several types of torque wrenches according to the structure and the method of torque measurement.
- Point2・Preset type torque wrench which clicks at the set torque is the typical type of torque wrench.
The tightening torque is increased with each "click" transmitted to the grip.
The specified torque of the swing arm pivot was 90Nm, so I put a preset torque wrench set to 90Nm on the torque tester..8Nm, which was almost the same as the set value, but it clicked twice in succession.!and the second time you click on it, 98.At 8Nm, it was about 10% higher than the set value, and when it was clicked three times, it reached 109Nm, 20% higher. When purchasing a torque wrench, people tend to focus on the error of the product itself, but there is no point in using a torque wrench if it over-torques by 20%. There are many users who unconsciously click their wrenches on and off, but it is important to know that every time they do, they are over-torquing.
Preset torque wrenches have a spring and cam inside to let you know when the set torque has been reached with a click and a response. When the torque is set, the spring is pushed down and pressure is applied to the cam. When you tighten the wrench, the cam is tilted and when it is balanced with the pressure applied by the spring, the cam collapses and the wrench clicks.
When the torque is set, the spring is contracted in the same way as the preload adjustment of the front fork, and the spring is pressurized in advance to increase the repulsive force. Therefore, if the set torque is small in the measuring range, it clicks with little force, and if the set torque is large, the force applied to the wrench must be large.
There is an important point that should be observed about this click and response. It is"A click when the bolt is tightened.!is only one click."That is to say. Some riders and professional mechanics use torque wrenches and click!However, there is a possibility that the torque measurement will be ruined by this method.
It's been proven in tests using a torque checker.The actual tightening torque is higher the second time than the first time and the third time than the second time.The reason for this is due to the construction of the preset torque wrench, which compresses the internal spring when setting torque. The first time the torque is applied, the camshaft collapses with the preload of the spring. The third time, the actual tightening torque will be higher.
As an example, click three times with a torque wrench set to 90Nm.!You may think that 10% or 20% is not a big deal, but it is. If the default torque is higher than the set torque, the torque wrench will be useless.
Click twice or three times with the intention of double-checking.!and click when using a torque wrench, understanding that the tightening torque is increased by clicking!is always important to finish in one go.
- Point 1・The actual tightening torque increases with each click of the preset type torque wrench.
- Point 2 - Click only once to tighten to the set torque.
