Center stands and Isolastics

I just had a friend tell me that storing a Commando on its center stand is hard on the Isolastics. Is this true?

Jonez69 said:

I just had a friend tell me that storing a Commando on its center stand is hard on the Isolastics. Is this true?

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Assuming that you are talking about the later models with the center stand on the cradle:

Probably somewhat true, but IMHO, the side stand is worse. The frame can buckle at the side-stand mount, especially on a MK3, the isolastics have uneven pressure on them, oil collects in the intake valve area with no drain, if left sitting long and wet sumping happens the stator studs can allow oil to leak into the primary as can the crank seal more readily than on the center stand.

On the center stand there's only the weight of the frame and things attached to it pushing down on the rear isolastic since the center stand is holding up the power unit and swingarm.

The internet has provided a huge number of things to worry about that NOBODY worried about back in the day. I characterize this as one of those things to continue NOT worrying about!

marshg246 said:

.. if left sitting long and wet sumping happens the stator studs can allow oil to leak into the primary ..

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??

Conversely, the 68-70 models supported by the frame have the weight of the power unit 'hanging' in the frame from the isolastics while on the center stand. This is more weight than the frame, tank, seat, etc. so these are probably more susceptible to distorting the rubbers over time. My experience has been that both have shown distortion in the rubber when disassembled after 40+ years. When I do a complete frame-up rebuild I replace the isolastics as a matter of course. Otherwise if vibration or noticeable sag is observed I recommend replacement. Just another part of Commando ownership.

Jonez69 said:

I just had a friend tell me that storing a Commando on its center stand is hard on the Isolastics. Is this true?

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I definitely think that is true.
Other than very short term, I put my bike up on a small scissor-jack on the lower frame rails - much easier on the rear isos.
I have also now taken to then putting the centre stand up (to save the spring)

Another "good" option would be to use a paddock stand.
Cheers

I have never relied on any stands when parked up on my 850 Featherbed I don't have a centre stand , I do have a clamp on side stand but the foot has broken off, but can still use it sometime, there is always something to lean the bike on, at home I use a car jack stand under the foot peg or 2 one under each foot peg they are set so just slide it under using 2 is good to check oil and having the bike standing straight, I do have my scissor jack but the stands are there and easier to just slide under the foot peg, been doing this for about 40 years now on my Norton.
I also use the car stands for my Thruxton when checking oil I have 2 machined round bars that slide into the hollow axel and stand the bike on them with the car stands, a lot easier than setting up the scissor jack, adjusting the arms and winding it up.
But then I don't have Isolastics to worry about, but long term sitting on Isolastics might have a problem leaving the bike on the stands.

Ron L said:

Conversely, the 68-70 models supported by the frame have the weight of the power unit 'hanging' in the frame from the isolastics while on the center stand. This is more weight than the frame, tank, seat, etc. so these are probably more susceptible to distorting the rubbers over time.

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My 1968 Fastback suffered badly from isolastic sag to the extent that the cradle was starting to eat into the cross bar that runs under the engine. The vibration through the bars was hand numbing. I stupidly got used to it, until a friend with a Commando rode it and pronounced it in serious need of rehab.

I lean mine against my shed wall it takes less room and easier to get more bikes in and out

If the iso rubbers need replacing, replace them. They are rubber parts; they age/wear out. I installed new ISO rubbers in 2008. They have been there ever since and the bike is always on its centerstand while in the garage, They still function perfectly but if they suddenly seemed to be in need of replacement, I'd consider "every 17 years" to be a reasonable replacement interval.

Do Isolastics harden with age? I replaced them 15 years ago. I seem to feel more vibration than I used to.

paddock stand

JimNH said:

Do Isolastics harden with age? I replaced them 15 years ago. I seem to feel more vibration than I used to.

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When you remove old isolastic rubbers from the housing the hole is no longer in the center. Presumably that would make the rubber on the compressed side denser and harder.

For my 850 Mk2, I made up a spring assisted head support, inspired by how ludwig did it.
It is set up in such a way that, with the bike on the wheels, the centres of the isolatics are in line with the holes in the frame mounting tabs.
So no static forces on the rubbers.
I got the feeling that for this bike from then on, the isolastics rubber shape change would be more due to prolonged periods of parking on the centre stand than from road use.
I park the bike in the garage on the side stand next to a wall, with a few blocks below the side stand so that it leans over just a little bit towards the wall.
No danger of accidently tipping over.

Something else I'll have to worry about!!

JimNH said:

Do Isolastics harden with age? I replaced them 15 years ago. I seem to feel more vibration than I used to.

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Harden: Yes, Flatten: Yes.