The front suspension of the old R75/5 was in pretty bad condition. The headlight ears weren’t sitting straight due to perished rubber bushings, the aluminium fork tubes were pretty tarnished and the steering damper assemble under the bottom triple clamp where all rusted. The top plate triple clamp and the large central nut that the damper rod runs through had been painted black at some stage. These were originally plated steel (probably cadmium plated).
The goal was to replace all the seals and other worn components and bring the finishes up to much closer to how they would have been originally.
To get started I removed the steering damper assembly. This is achieved by unscrewing the large central damper and then removing the damper plate where it connects to the frame under the lower triple clamp.
Then the wheel was removed by loosening the lower fork cinch bolt on the left hand strut, removing the brake line and then unbolting the right hand axle nut and withdrawing the axle from the wheel. Don’t forget to remove the brake torque arm which connects the brake plate to the fork (essentially prevents the brake surface from spinning when the brake is applied).
I had also removed the mudguard the handlebars at this point.
I decided to keep the forks clamped in place in the lower triple clamp if possible as this would reduce some of the complication of reassembly. The upper triple clamp plate is secured with the central steering nut and a large nut at the top of each tube. However the tube top nuts are covered with caps which require a pin wrench to remove them. The pin wrenches I had didn’t fit so I had to improvise. The arrangement shown with two allen keys and a screwdriver worked very well. The top of the right hand cover was very badly scratched presumably from someone “improvising” in the past, but my technique resulted in no new scratches! Once the covers were removed I was able to remove the three nuts allowing the plate to be removed. I had to buy a new tool for this as they are very large nuts- a 38mm socket. My trusty cordless impact wrench removed them easily. The springs can then be withdrawn from the tubes. I kept these oriented so I can replace them the way they came out.
At this stage I was able to remove the headlight ears and the indicators. You should note how the indicator wire is routed through the ear into each indicator. Then I was able to remove the fork assembly from the frame head tube. I removed the steering bearings and inspected the outer races top and bottom. They weren’t in bad shape with some mild brinelling. I removed them using the Kukko puller I had bought for the last project.
The lower steering bearing was removed in a similar way to the r65 project. I first used a small bolt cutter to cut the cage and remove cage and rollers. Then the inner race was very carefully cut at two angles using a cutting wheel on the Dremel. When cut almost all the way through a sharp blow with a cold chisel was sufficient to remove it. The new bearing can be installed by heating it and using a piece of pipe to knock it into place.
The next step was to remove the sliders from the fork tubes. I did this on my workbench. The rubber plugs on the bottoms of the sliders were removed revealing the small nut for draining the forks. This nut also secures the inner rod assembly. Once it is removed and the forks drained, the large bottom nut can be removed using a huge socket. The copper crush washer will be replaced and is included in most rebuild kits.
The sliders can then be removed and the main seals at the top replaced.
To get the piston assembly out of the stanchion look for the little circlip and remove it. Then there are two threaded sections to remove. The photographs below show the various bumpers and bushes which need to be replaced and the correct order for them in the assembly.
To reassemble the forks in the frame is basically a reversal of removal. There were two washers which sit on top of the upper triple clamp which were missing on my bike. These are quite important as without them the large upper nut will bottom out in the stanchion thread without putting pressure on the plate. This will cause the headlight ears to not compress the indicators enough. I think it is one of the leading causes of droopy indicators. Be sure to measure that the amount of stanchion above the lower triple clamp is the same on both sides (160mm). It helps to have the front axle in the forks during this procedure to keep things even.
