Type 2-10 Yamaha KYB 34-38 1976-78

  • 34mm RD400 1976-78
  • 36mm TT/XT500 1977-78
  • 38mm YZ250-400 1977-78

 Dirt and Street - KYB

This is the stock damping rod head. It is threaded on and held in place with a roll pin. It does not have to be removed from the damping rod to modify it.

As shown, the steel head has outlet ports exiting the sides. 

This is a side view. The top of the head must be machined off down to the bottom of the outlet holes.

The damping rod head must be machined off flat just below the outlet holes. This is best done on a lathe but can be done with a hack saw and a file if you are REALLY careful (don't blame me if you mess it up).

This is a cross section of the completed damping rod head. If you look closely near the top, you will notice there is still a lip from the head covering the end of the damping rod tube.

Here is another angle. Leave the roll pin in place.

Enlarge the original compression holes to 6mm (1/4") - 8mm (5/16") depending upon size of damping rod and add one more set above (left) at 90 degrees to the last set for total of 6 compression holes.Carefully deburr.

The new Top-Out Springs (FRST K3801) for 38mm forks are shown on the damping rod. They allow the use of modern rate springs and increase travel by 7mm.

The original Top-out Springs are below. The original springs very long top out springs require the use of additional air pressure. These are found in 36 and 38mm Dirt applications. Street forks have standard Top-Out Springs.

The adapter is a sleeve with a piston band, that goes between the damping rod and the Emulator. Notice: If Adapter is recessed that side of the adapter goes up, towards the Emulator. Some Adapters are not recessed, varries by kit and applicaiton. 

The main spring holds it all together.

Here is the completed assembly. Notice the new Top-out Springs as well as the Bottom-out Cone on the right.