Hello everyone.
When you work on your motorcycle, most jobs involve loosening and tightening screws, bolts and nuts.
I think the bolt you loosen and tighten most often is the drain bolt when you change the oil.
If the drain bolt works loose, oil leaks out. If you overtighten it, you can damage the crankcase.
So when you tighten bolts and nuts, it is very important to use a torque wrench and tighten them to the correct torque.
That is why I use a Tohnichi torque wrench for my maintenance!
...That all sounds very knowledgeable, but the truth is that until recently I had not been using it correctly. So here is the correct way to use one.
First, this is the torque wrench I use.
It is a Tohnichi QL25N-MH.
Its adjustable range is 5 to 25 N·m.
I originally bought it for engine work, so it is a model for fairly low torque settings.
And I used to hold it...
...like this, and tighten until it clicked, and that was that.
But one day I was looking at Tohnichi's website and found a page on how to use their wrenches correctly. I learnt one thing after another that I had not known.
For the details, please see the manufacturer's own website.
https://www.tohnichi.co.jp/download_services#type_2
That is Tohnichi's download page (in Japanese).
Look for the document on how to apply force, loosening, and tightening left-hand threads (No. 19).
Source: Tohnichi website (in Japanese)
According to this document, with a signal (click) type wrench like my QL, the torque changes depending on where you hold the handle. The correct way is to hold it centred on the line on the grip (the effective length line).
That line is the part marked with the red arrow in the photo above.
(To be honest, I thought this line was just decoration... It actually has a purpose.)
Hold the wrench centred on this line, and pull at a right angle to the wrench (within ±15° up, down, left and right). Also, stop as soon as it clicks.
These days I hold the wrench centred on the line on the grip, and I stop as soon as it clicks. I use this torque wrench for oil changes and for removing and refitting the fairings on my XR BAJA and X-ADV.
Tohnichi also has an English website (Tohnichi America) with technical information on torque: Torque Technical Data (Tohnichi America)
Tohnichi's website was full of useful information,
for example about how to tighten screws and bolts, and about axial force (clamping force).
I suspect there are many other things in motorcycle maintenance that I don't know, or that I thought I knew and believed were right but are actually wrong.
This taught me how important it is to check things properly with a reliable source.
The torque wrench I use is the Tohnichi QL25N-MH.