Y-1 and Y-2 Cylinder
TZR125 Track Bike > Cylinder/Head Changing's
There is not much know about the differences between the Y-1 and Y-2 cylinders on a TZR125 4DL engine
But it looks like they have a 1,5HP differences between them.
What I can measure, it seems that the Y-1 has a slightly aggressive port timing
But it looks like they have a 1,5HP differences between them.
What I can measure, it seems that the Y-1 has a slightly aggressive port timing
Its more in the 1,0mm's then in the 1,0mm's
Here you have the Y-1 and Y-2 cylinders
Here the Y-1 cylinder
You can see clearly the port's have been reworked
You can see clearly the port's have been reworked
This is relative common by a fresh hone.
But this is done at the factory, as it is a stock piston
But this is done at the factory, as it is a stock piston
Here the Y-2 cylinder.
You can see clearly the port's have not been reworked
You can see clearly the port's have not been reworked
This one uses the first oversize piston.
So logical the oem made work is gone
So logical the oem made work is gone
To see if could find a differences between them, made a port map off the two cylinders.
There are many ways to do this, I use the piston to keep the paper on its place.
Make my finger a bid dirty and rub gently agents the paper until it leafs a mark.
There are many ways to do this, I use the piston to keep the paper on its place.
Make my finger a bid dirty and rub gently agents the paper until it leafs a mark.
After making it a bid dirty, it leafs a nice mark
This is what I found with the Y-1 cylinder
This is what I found with the Y-2 cylinder
Here the difference between a Y-1 and Y-2 cylinder.
It is difficult to say if these differences are good for a 1,5HP.
Measurement that precise are hard to do, but it looks like the Y-1 cylinder has the better papers.
Measurement that precise are hard to do, but it looks like the Y-1 cylinder has the better papers.
Will see if I can find more info.