Install Fork and Seat Locks
I show how to remove these here:
There are two different size fork lock cover plate nails. The 1983 uses the same nail that secures the /5, /6 and early /7 VIN plate to the front of the steering head:
- Part # 51 25 1 242 647 NOTCHED NAIL – 3X9 (from 09/81)
The /5, /6 and early /7 fork lock cover plate nail is larger diameter and longer and will not fit the cover plate nail hole for the 1983 bikes.
- Part# 07 11 9 944 651 NOTCHED NAIL – 4X10 (to 08/81) <– DO NOT USE
Here is a short video showing how I install the locks
VIDEO: 1983 BMW R100RS Install Fork and Seat Locks
Install Fork Lock
The fork lock mechanism includes the tumblers, a cover plate and a special “nail” to secure the cover plate.
The fork lock mechanism requires the key to be inserted into the lock to install it into the hole in the steering head.
With the key in the lock I catch the screw on the edge of the tumbler on the side of the slot the blade moves through and then turn the blade of the tumbler counter-clockwise to align the blade with the slot so I can slide the tumbler into the hole.
The tumbler will come out of the hole if you turn the key. The lock cover plate is what prevents the lock from coming out. It is secured by a special “nail” that is driven into a hole on the face of the tumbler housing at the 2:00 position.
Install Seat Latch Mechanism and Lock
The seat latch mechanism has a housing and cover plate secured by two long Phillips head screws that screw into tapped holes in the sub-frame. Inside is a spring, a pivot pin, a pivot arm and a button that operates the mechanism.
The seat lock includes the lock, a retaining ring and a small Phillips head screw to secure the retaining ring on the backside of the lock. There is a pie-shaped section of the retaining ring that fits over the threaded hole on the backside of the lock where the Phillips head screw goes.
The keyed tumbler has a ridge that aligns with a notch in the hole in the sub-frame.
I install the lock first.
I assemble the seat latch mechanism before installing it in the sub-frame. I lubricate the button with some wheel bearing grease and install it through the hole in the housing so the shoulder of the button is inside the housing.
I insert the pivot arm so the hole in the arm aligns with the holes in the top and bottom of the housing with the ends of the arm sticking through the slots on the ends of the housing. The finger on the arm butts up against the backside of the button.
The pivot pin fits through the spring and slides through the holes in the top and bottom of the housing. The pin is secured by two snap rings. But one of my snap rings broke from corrosion when I removed it. I use a piece of garden wire to make a replacement snap ring. I remove the green plastic coating, put the wire in one of the grooves in the pivot pin and twist it tight leaving the twist ends of the wire exposed. I orient the pin so the wire is on the bottom. If it fails the pin will stay in place with the top snap ring keeping the pin from falling out.
The spring has a leg on one end that fits against the pivot bar. The over end butts up against the cover plate. When the plate is attached with the two long Phillips head screws it compresses the spring.
I insert the assembled latch mechanism around the lock. I install the back cover starting with the Phillips screw next to the lock and thread the screw in a couple turns. Then I push the back cover plate toward the housing to compress the leg of the spring. You may have to use a small screw driver to encourage the leg to slide along the cover rather than dig into it. I insert the Phillips screw near the button and tighten it down and then snug up both screws so they are tight.
After assembly, I press the seat latch button and observe the movement of the pivot arm through the holes in the top of the sub-frame and the seat latch housing that the pin on the bottom of the seat goes through. The bar should not be visible in the hole when the button is pushed all the way in.