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Well, what have I bought?
As part of my fettling/restoration of my 3½ I thought I'd renew the fork oil. Having removed the fork caps I noticed things didn't match on both sides.
The offside fork leg contained what looked like a pretty standard spring with the long shroud over the top. No shroud on the nearside as the spring is a larger diameter. Closer inspection shows the nearside spring to be progressive wound and 505mm long. The offside spring is constant rate and is 457mm long. The top spacers are both the same length and came to just below the top of the fork leg. The different spring lengths led me to conclude that all is not right lower down in the fork leg. Sure enough, different damper rods. I seem to have a standard damper rod on the nearside combined with the progressive (Hagon?) spring, meanwhile on the offside I have a standard spring (not sure what the correct length should be) with a mystery damper rod. Can anyone identify the damper on the left please? Edit to add: oops, I meant the one on the right. Now identified. Thanks Norbert

Currently faced with replacing one or both of the springs and one of the damper rods.
On the standard rod there is a spacer that has a counterbore. Does anyone know which way up this should be? I'm not sure if it's been assembled correctly.


Thanks and regards
Howard

The left one is the normal Marzocchi rod. The richtig one Paioli as mounted in the drumbrake forks. I supose that the stancions have different threads for the top screws? The bottom parts of the legs are both for drum brakes or discs?

Hi Norbert,

that's good information - thank you!

You're right -the thread is different at the top of the stanchions. I hadn't noticed that.
I had noticed that the stanchions are a different length though.
The stanchion with the Paioli damper has a finer thread and the stanchion is 10mm longer. The circlip at the bottom is further up the tube than on the Marzocchi one so that kind of compensates. However, the counterbore on the Paioli stanchion goes a lot further up inside. I now understand the longer sleeve at the bottom of the Paioli damper.
Anyway, I've bought a second hand Marzocchi spring, shroud, and damper rod from Mdina so that should make things equal again, or more equal than they were. I'll turn a new sleeve to enable the Marzocchi damper to fit the Paioli stanchion.
My fork lower legs are both Marzocchi disc brake items.
I did wonder about splashing out on Hagon progressives but that's always something I can do later on if I don't get on with the standard set up. Might be fine as I am very light - akin to the 'Italian Youth' that someone somewhere else said the Morini was originally set up for

Light weight champion for light weight bike
I would begin with 180 ccm of Sae 15, if riding a bit sporty. You allways can fill up to 200 ccm. But first I'd give the air pillow a chance

norbert wrote: ↑12 Dec 2024 23:46 Light weight champion for light weight bike

A lot of truth in that

I'll try what you say with the oil. Was torn between Sae 10 and 15

Thanks
H

Just to report back on this, as a very happy bunny.
I had my first ride out this afternoon since rebuilding the front end, and what a transformation!
The forks are now fitted with matching original springs but despite buying a Marzocchi damper rod to replace the Paioli item, I found it too problematic to install in the Paioli stanchion. In the end I reasoned that the damping characteristics would be pretty similar so decided to live with a Marzocchi damper in the Marzocchi stanchion and a Paioli in the Paioli stanchion for now.
I made up new, longer, top spacers that stick out around 3mm before the caps are fitted, so there is an amount of preload that was missing before.
New head races, cups and cones fitted (used but better than what were on there).
Following advice on here, I'm running the tyre pressures at 32 front/36 rear compared to the manual's recommendation of low 20s.
Finally, I dropped the spring platforms on the rear shocks to the lowest setting.

I think the problem with the bike as it was, was that the forks were sagging and the back end was jacked up, resulting in too steep a head angle.

The combination of preload in the forks keeping the front end up, and the slight lowering at the back has slackened the steering angle to where it should be and the absence of notchiness in the head bearings has eliminated all the nervousness and wandering in the steering. The nosediving under braking has also disappeared. The bike is now superbly stable and confidence inspiring, and a joy to ride. I would have been out longer but my hands were numb with cold. I remember those days - gritting my teeth afterwards as my hands warmed up. First impressions are that it handles better than the 3½ Sport I had back in the early 80s, which always felt disappointingly loose at the front. I think that was because I was young and foolish and didn't pay enough attention to suitable tyre combinations and suspension setup.

Thanks to all who have helped with advice on this, especially norbert

That's fine!
Nos you'll see that this bikes have had one of the best chasis in their category back n the 70ies. And it's still very noble