The following table is the shim stack for a 1989 YZ250.

I am making the assumption that the stack is the stock configuration

but I am not the original owner. The stock stack was for a 155 lb rider

with a 5.2 kg/mm spring. Dimensions are in inches.

Quantity
Nut End Of Shaft
Comments
1
Nut
This end considered up
1
Backing Plate
Check Valve
2
.005 x 1.260
Check Valve
2
.028 x .747
Washer
1
.012 x .865
Shim High Speed Rebound
1
.012 x .942
Shim High Speed Rebound
1
.010 x 1.023
Shim High Speed Rebound
1
.010 x 1.100
Shim High Speed Rebound
1
.010 x 1.178
Shim High Speed Rebound
4
.010 x 1.338
Shim High Speed Rebound
 
1
.004 x .945
Shim Low Speed Rebound
1
.010 x 1.338
Shim Low Speed Rebound
 
Piston
Port with raised inset goes down
 
6
.006 x 1.495
Shim Low Speed Compression
1
.004 x 1.101
Shim Low Speed Compression
1
.004 x .905
Shim Low Speed Compression
 
1
.010 x 1.495
Shim High Speed Compression
1
.010 x 1.416
Shim High Speed Compression
1
.010 x 1.338
Shim High Speed Compression
1
.010 x 1.259
Shim High Speed Compression
2
.010 x 1.181
Shim High Speed Compression
1
.010 x 1.124
Shim High Speed Compression
1
.010 x 1.102
Shim High Speed Compression
1
.010 x .905
Shim High Speed Compression
 
1
Base