Hello Mark,
the sliders and stanchions on the original Monolever fork may well be worn out due to the inevitable wear and tear, but also due to damage, neglect and bad servicing by previous owners. These forks were designed an manufactured in the 1980s. They still work sufficiently if maintained properly, but the Paralever forks from the 1990s are superior in every aspect: The damping system is supposed to be much more sensitive, the stanchions are 41mm and they do not wear out the sliders.
I am currently working on a Monolever which has received such an R 100R fork, but the bike has not been launched yet (still waiting for the body parts to be painted). In a few weeks I will be able to provide first-hand information
What I can tell you right now is that
- the Y-spoke wheel and the Monolever front axle fit perfectly
- the Monolever brake calipers fit perfectly (However, my bike has the R 100R brake disks, so you have to check whether the Monolever brake disks have the necessary offset
- you can also use the R100R four-pot calipers (along with a 15mm master cylinder)
If you are not keen on riding a bike that is 100% original, I would suggest using the R 100R forks.
best wishes
Alfons