Type 2-7-0 Husqvarna CR250 1972 
 - 35mm

1972 - Thick Piston Ring Stock

This is an "RT Only" installation. It requires extensive machining.

1972

The 1972 is a bit different than the 73-74. The stock 1972 has a check valve in the bottom of the chrome tube. It has a series of small holes running the length of the damping rod and the rod itself is tapered.

 

Click on the image on the left to open the .pdf for specific machining instructions. This doc explains what to do to 1972 models. 

Be sure to bore the ID. The stock ID is way too restrictive and will cause harshness if not drilled.

Drill the two existing large compression damping holes to 6mm (1/4") and add 1 more sets of holes (4 holes total) at 10mm increments above the stock holes. Each set must be at 90 degrees to the last set. See .pdf.

Fill the top 3 sets of small holes with weld or JB Weld or other good epoxy. It is best to prepare for epoxy or welding by cutting a chamfer with a countersink so there is fresh metal. file and sand the high spots evenly with the existing surface. Do not remove existing metal from the damping rod surface.

 

 

 **Critical

The ID of the damping rod must be drilled out to 9.5mm (3/8") to a depth of 175mm from the top. This is best accomplished on a lathe.

 

Stock on top.

 

 

Mod on bottom.

 

It is vital that FEGV AD3005 P Emulator Adapters are used with FEGV 3001 Emulators.

Below is the completed assembly.