I have a 1980 Darmah which was rebuilt around 7 years ago and hasn't been used since. The forks were very 'stiff' with little suspension or damping in evidence at all. I've checked that the wheel is fitted correctly and the legs are not twisted. When I drained the oil, there was around 180cc in each leg, but very discoloured and quite viscous - possibly 20 grade or more. The spring lengths were similar, but I can't find what the spec is, so have no idea if they are right or not. The spacers below the top nut which are supposed to be 35mm long were actually 55mm but had been marked by someone at 35mm, as though they had meant to cut them down. I cut them to the correct length and refilled the legs with 10 grade fork oil and they are much better, but still not great. The travel seems about right (can't be certain as the brakes are too weak currently to bottom them out- another job) but they don't really iron out the bumps. I'm thinking to try lighter oil and possibly removing the spacers altogether - the forks would still be slightly loaded without them, but any suggestions or advice would be appreciated.
185cc is correct tube length should be 600mm Forks should be fully extended with the weight of the bike on them ( not the rider) stiction is a problem with these forks and so is spring length if the springs have gone soft. If you dont want to cut tubes to give the correct preload, 2p coins do just as well
Also dont forget to expel the air in the tubes or you will get a lock. slacken the screws in the top nuts and bounce the forks as far as you can then tighten the screws again
Where am I measuring this from and to? The length from the top of the fork to the bottom is 800mm. Mine has 26mm compression with just the bike's weight, so I'm guessing the springs have had it. What do you recommend to replace them with? Are the YSS progressive springs any good?
