2-11 Marzocchi 40mm

    Flat-Top

    BMW R80GS/R100GS 1987-97

On this fork, the left and right fork legs are different.The right leg has a Standard Rod that creates both compression and rebound damping. The left leg has a tapered rod and creates Compression Only.

This kit has only one Emulator. It gets installed on the Standard Rod in the right leg. It will create both compression and rebound damping.

The tapered Compression Only rod creates a very small amount of compression damping through most of the stroke and really is only effective near bottoming. We will not make any modifications to the Compression Only leg other than spring rate and oil.

Note: If your forks have ever been rebuilt before the tubes and/or damping rods could be reversed. The sleeve with the check valve must be paired with the rebound rod.
 

COMPRESSION ONLY LEG - Remains stock. Take the left fork leg off the bike and disassemble it. An air impact and a long Allen socket helps a lot. For stubborn Damping Rod Allen Bolts, use a drift and beat on the head of the damping rod bolt to jar the thread loose (I know, it seems a little cave man but it works).

Remove the internal circlip in the bottom of the fork tube to remove the aluminum sleeve and damping rod assembly.

You can identify the compression leg because the damping rod is tapered its entire length and has a piston ring with triangular faces. The sleeve in the bottom of the compression fork is plain (it doesn’t have valving in it). You will not be modifying the compression leg. If the components are correct you may reassemble it.

STANDARD LEG (stock) (should be the right leg) - Gets modified for the Emulator.

When removing the sleeve at the bottom of the fork tube there should be a check valve, plate and spring.

Make note of the order and orientation for reassembly. The image below does not show this detail – sorry. (If you have this fork and can send us a picture that would be cool.)

STANDARD LEG (modified)

Drill four 8mm (5/16”) additional compression feed holes in the damping rod so you end up with 5 holes. The existing hole is already larger than 8mm. When drilling new holes, space them lengthwise at 10mm (7/16") increments above the existing holes (exact placement is not critical). Each set of two holes must be perpendicular to the last set to maintain rod strength.

After drilling, chamfer and deburr the compression holes, inside and out.

The image below has the old Adapter without a Piston Ring. We have found that the damping is more consistent with a Piston Ring. The new one has one.

Consult your DVS Setup Sheet and set up the Emulator valving. When assembling the fork leg be sure to install the Adapter then the Emulator.

Follow the  Standard Emulator Installation Instructions for Preload and Oil level instructions.
 

COMPLETE THE ASSEMBLY

When assembling the fork leg be sure to install the Adapter then the Emulator.

Follow the  Standard Emulator Instructions for Preload and Oil level.