Most people set their gauge at around 5 inches from the piston. This is because if you set it too close it will read very high i guess.jonashford wrote:regarding this 4 inches away from the piston measurement. What exactly does the mean??? straight line? when the piston is tdc or bdc?????
any one know for sure? Also does it matter how far in the probe is?
If I spend the extra for a koso id like to get it right, if I havent already!
It should be measured like this......take exhaust off just stick your finger up your exhaust port and see if you can feel the skirt of the piston (do this when engine is cold!

When measuring the pipe, the measurement should follow the angle of any bends.
How far the probe goes in can effect readings. There is no garaunteed method here but i would say anywhere between 10mm actually sitting inside the pipe to half the diameter of the pipe.
The main thing is that you know what your bike is reading when its running correctly so you can tell if its gone unusually low or high, as both these can spell potential doom!
EGT's can vary greatly between different set ups.
Timing can effect EGT's greatly as well! Lets say your running 16 degrees and then you advance to 19 degrees.......surprisingly, it is likely that your EGT temp will go down and your cylinder head temp will go up!
There are many variables, so get to know what your bikes normal EGT reading is.