Isolastic once again.

As you may remember, I overhauled the Isolastic on my Commando many moons ago. It was a very satisfying winter project that - as usual - took way too long even though I could have had it done in under a week if I'd had some free time.

The result was unquestionably a better motorcycle, an improvement measured in megaparsecs, simply put, a proper Commando.

Then Alessio decided to carry out the same upgrade on his Commando, going from the original shim type units, to the vernier adjustable that can be retrofitted to all Commandos.

Seeing as I had already done this on mine, we decided to try this together on his Fastback, which also has a belt drive primary and is therefore an almost identical set-up to mine.

Removing the primary was surprisingly quick and aided by the fact that almost everything that had to come off was barely finger-tight. Good grief!

We found an unacceptable amount of rust in the front mount, and although the rubber itself was showing some wear, I have seen much worse. The front mount itself came off the bike with no resistance, probably because Alessio's crankcases are the original ones and in all likelihood a hair narrower than mine (which are a contemporary reproduction).

A hydraulic press sure comes in handy for this (but isn't strictly necessary):

This particular bike is gradually returning to a "close to stock" look, and in that effort Alessio will be refitting the rear chain guard; to do that, he needs to go back to a 520 chain, and while we had the gearbox sprocket within reach, we replaced it with a new one (still 20 tooth). Again, the mainshaft nut came off with very little effort (i.e. worryingly it was barely more than finger tight).

Everything there is now back on, tight and properly secured.
Moving onto the rear mount, this is where things get trickier, and with one substantial difference from my Commando: Alessio's bike is a 1970 model, which means the center stand is mounted to the main frame, as opposed to the gearbox cradle as it is on mine.

Aside from the fact that he has actually removed the center stand altogether (you rebel, you!), we still need to consider a different way to support the engine-gearbox-swingarm-wheel as we separate that sub-assembly from the mainframe.

The exhausts being tied to both, we unbolted the Z-plates to let them move without the risk of damaging anything (or making things harder for ourselves).

The head-steady on this bike is the original type, made up of the same rubber mountings used for the silencers, as opposed to the actual Isolastic upgrade that's fitted on my Fastback. This too was unbolted to allow extra room to move, as were the ignition coils, rear mudguard, oil tank (actually removed), air filter, battery tray and rear shock absorbers. Yes, that is a lot of stuff, but the alternative would have been to remove the engine altogether and there was no way we were going to do that.

Because of the different position of the bracing tube on the 1970 frame, the operation to get at the rear Isolastic mounting was significantly trickier and harder than on my (1971) machine. This is something I was not expecting, although with some effort (see long list above) we managed to get it done.

Above: finally able to get at the rear mounting (only just), Alessio scrubs it clean of old rubber particles that were stuck on. The rubber mountings themselves were showing signs of compression (the metal tube being way off-center) and were probably not able to provide much in the way of cushioning anymore.

Below: the new unit in place (minus the dust cover).

The front Isolastic gets replaced on the bench and is obviously a much easier thing to do.

Meanwhile, these two keep guard on the shed:

Ferocious.
The grey one is (kind of) a Manx cat. He lost his tail in an accident but he has a good life nonetheless:

We can now begin to realign the mainframe and sub-assembly, bolting the front unit back on, the Z-plates with spacers, nuts, bolts and washers all accounted for, and finally the long mounting bolt/stud that links the whole motorcycle together.

Everything else that has had to come off or moved out of place goes back to its rightful place aboard the machine, ready to ride again at top speed. Fun fact: Norton Commandos are known to set off nearby seismometers due to the huge amounts of torque they unleash on the ground; however, thanks to the Isolastic system, the rider is unaware of the tectonic shift going on underneath the bike, and can concentrate on chasing the vanishing point to the next bend.

This was a good opportunity to give the clutch plates and basket a good clean; outside and in the winter sun:

Most of the plates were stuck together, the basket was predictably dirty (gearbox oil) and Alessio appears to be missing one friction plate, we'll look into that later on.

Below - Happiness is: wrenching on a motorcycle!

I'm glad we were able to get this done together, in a relatively short time and with no major mishaps.
Alessio now has to find the right setting/adjustment of the new Isolastic to suit his Norton and his riding style (hint: it's called a Fastback), and while adjusting the vernier units is certainly fiddly, it is far, far easier than dealing with shims.