they go by size not year
No, a cylinder from a 2001 YZ125 will not fit a 2004 YZ125. Although both models share the same basic engine design, there are differences in the cylinder and porting that can affect compatibility. It's always best to use parts specifically designed for the model year of your bike for optimal performance and reliability.
Yamalube motor oil.
No - the bore for the cylinders are different
well on my 87 yz125 i take the drain plug out of the bottom of the motor to drain it then put it back in... then there is a little black like cap by the kick starter where you put the oil back in i use gear saver for mine...
whenever it is fulli use 1 and a half quarts in my 03 yz125
BR9EG NGK(resistance type) is what the owners manual says to use
i have a yz 125 and i use 40:1 so 125ml to 1L
No. The first use of Nikasil by Yamaha on the YZ appears to have been on the 1989 YZ125. One really easy way to tell is to use a magnet. Nikasil over an aluminum bore is non-ferrous where as the steel sleeve obviously is. If the magnet sticks, it is a steel liner.
Hydraulic cylinder use a liquid medium, often some type of viscous oil, in the cylinders and can be subject to higher pressures then pneumatic cylinders which use air or some other gas and work under a lower pressure.
All cars that use i4s, v6s, i6s, v8s, v12, w12, etc all have cylinders, because they use the same kind of engine as the vast majority of cars. The only modern car that I know of that doesn't have any cylinders is the Mazda RX-8, which uses a different kind of engine called a rotary engine (GOOGLE IT)
The number of cylinders in an airplane engine can vary widely depending on the type of aircraft and its engine design. Small general aviation aircraft often use piston engines with 4 to 6 cylinders, while larger aircraft may have engines with more than 12 cylinders, particularly in radial configurations. Jet engines, on the other hand, typically do not have cylinders as they operate on a different principle, using turbine technology instead.
Hydraulic cylinder use a liquid medium, often some type of viscous oil, in the cylinders and can be subject to higher pressures then pneumatic cylinders which use air or some other gas and work under a lower pressure.