MexicoMike wrote:Seems silly to me. How do you get this stuff OUT when it wears and needs replacing. Commandos with standard ISOS did the IoM at 100 MPH... IMHO it's another one of those solutions for which there is no problem.

Ah come on Mike! The IoM bikes didn't have lightweight pistons and rods from JS Motorsport either. Doesn't mean they wouldn't have wanted them. Some ideas should be explored simply because they exist! Otherwise we might still be sailing off the edge of the world when we go over the horizon.

OK, from an "amusing experiment" point of view - sure, why not.

FWIW, at least as far back as the ancient Greeks, the earth was known to be round and its diameter had been calculated. So we haven't been worried about falling off the edge of the earth for at least 3000 years. And even the Commandos are newer technology than that... or are they?

http://www.msnbc.msn.com/id/38545625/ns ... e-science/

"These vehicles appear to be the first mechanical systems which combine the use of kinematics, dynamics and lubrication principles," Rovetta said.
"The wheels feature a real tire, made of a flexible wood rim, which adapts to soil irregularities. Moreover, the six-spoke wheels are made from elastic wood. This absorbs uniformly the loads transmitted by soil irregularity, so that the vibrations are damped by the wheel itself like the intelligent suspensions in modern cars," Rovetta said. The result is a remarkable level of softness and comforter.

Once a poured in place isolastic installed, its just the start of a sliding scale of SHORE measure curing.

Re: Hard vs Soft Isolastic Rubber

Postby john robert bould » Sat Nov 21, 2009 1:16 am
On the subject of Rubber, My little friend Dennis Lawton.Lawton Sales Weston Nr Crewe makes these rubber Isolastic's. I have collected the compound which is of a specified SHORE hardness. Problem is after molding they continue to CURE. ie get harder . Heat . TIME and to a lesser degree LIGHT continues the curing action. Having Seen my pal Colin's Harley 883 sportster "Shaking" i would have a guess and say the Norton set up is quite firm compared to. SO ..as your New Iso are on the stores shelf...they are getting Cured, Harder ....Dennis also produce's Spitefire[plane] rubber parts...these are kept is black bags... Den keep's the rubber compound is freezers to hold back the CURING process...Make's you think what's happening on a hot summers day

Here's some more on isolastic dynamics to loss sleep on formed in place concepts.
http://home.clara.net/captain.norton/cnn2sec33.html


From: John Pinkham
Date: Mon, 6 Jun 94 17:35:40 EDT

Diagnosis:
Vibration: up to 3000 RPM
o Rear engine mount tight- remove 0.005 shim
o Front engine mount O.K.

From 3000-5000 RPM
o Front mount tight- remove 0.005" shim

From 0-5000 RPM
o Both Mounts tight.

Don't support the bike on the centerstand when servicing the isolastics.

From: Chuck Kichline
Date: Tue, 7 Jun 94 10:52:31 CDT

> Diagnosis: [Snip]
I believe the best (and classic) method is the "night ride" where the analysis and adjustment requirements of the system is diagnosed thusly:

1) All tests should be made at 1000rpm intervals. Each interval should be tested for ~ 30 seconds.

2) All tests should be made in appropriate gear for use at that rpm.

3) Rider will position himself in front of an automobile who has turned on their headlights and is driving at an appropriate speed.

4) The rider will examine the pattern made in the rearview mirror(s) by the headlights for diagnostic wave patterns.

5) Diagnosis:
Figure 8 below 3000rpm
o Rear engine mount tight- remove 0.005 shim

Figure 8 above 3000rpm
o Loose front engine mount.

Horizontal line 3000-5000rpm
o Front mount tight- remove 0.005" shim

Vertical lines 2000-4000rpm
o Loose rear engine mount.

Squiggles at all rpms
o All mounts loose.

Handlebars squiggle at all rpms
o All mounts tight.

Two rock-solid spots above 5000rpm
o Blew your engine, stupid!

hobot wrote:... Problem is after molding they continue to CURE. ie get harder . Heat . TIME and to a lesser degree LIGHT continues the curing action...Make's you think what's happening on a hot summers day

Relatively speaking, how significant is the "continued" curing on these isolastic buffers over a typical lifespan?

I suspect a MUCH more significant issue is actual physical wear / deterioration, especially on the old style units that ALWAYS show significant ovality on the I.D.

Perhaps the wear, over time, and the continued curing, over the same time, cancel each other out (to a degree)...

pommie john wrote:Can't you get a similar result just by using Mk3 Isos and running them a bit tighter?

It's my experience with the vernier isolastics that you can set them to be comfortably smooth or stiffen them up for tighter handling. Whatever point of compromise between the two is a personal preference. Obviously, the front mount needs more slack than the rear and the rear is more critical for keeping the swingarm aligned. It is nice, though, to be able to whip your tool kit out at a roadside stiop and experiment. Can't do that with shims!

Don't forget that part of this equation is the lightweight pistons and rods, which changes the balance and decreases vibration (see Jim, I wasn't asleep in class after all). So the lesser vibration allows you to tighten the iso's to get better handling without sacrificing as much comfort. So a solid isolastic isn't so much of a goal in itself.

I have to admit I wonder why not keep the stock isolastics and tighten them down to no clearance. And I would also like to point out to the nay sayers that there are a number of people who are proud of their heim joint hinge-effect prevention devices. There must be something to this.

So will turn this back over to the more learned in the group with these questions:
1.) Would it be necessary to bond a solid iso to the mounting tube? Or could it float?
2.) How critical does it become to have as little friction as possible between cap and collar?
3.) Would it be a benefit to pour the isolastic so that it were proud of the mounting tube by a small amount so that it would be compressed when mounted?

Russ

After Bob Patton's device this is just academic to Peel. Bob says he stuffed 6 big rubbers in back to control the time-sag factor on his link leveling.
I may try my own poured in place or machined cylinder rear iso cushion to see if anything extra good happens or intrusion of vibration. Do understand that whether one realizes it or not, the freq. of engine vibration over laps and interferes with the muscle and joint nerve position-load-motion-tension- sensors and processing, so pilot fatigue and errors creeps in when slightest mistake or lack of notice > SPLAT* I trimmed Peel's donuts to half narrowed edges. Ah.

I've seen old doughnuts go both ways, harden up or soften in decay. I guess it depends on how well maintained a bike, best ones too dry to soak iso's in oil.
I don't know elastic property - chemistry, just bring it up to be aware over time.

I can sure tell the effect of engine resonance on tire grip in a number of conditions. No one else is mentioning the advantage of dampened power pulses.
I think pulse hook up along with narrow tires combine wonderfully in Commandos.
360 cranks have widest pulses. The inline 4's big bang'rs have longer gap between their 'big bang' than 360's BUT their 'bang' is really a very hi freq vibe over 100 degrees or so. Only takes one excess at limits to crescendo into SPLAT* I find my iso Commando the most forgiving in grace periods to my excesses or laxes.
I think above is a big reason to retain the isolated power unit, IF it don't upset bike and pilot. You can not separate the piston pulse freq- crank configuration and balance factors from isolastic function in hot cornering to lazy pilot cruise.

What I would like to try beside beefing up the rear iso pivot point is to somehow restrain the leverage of swing arm on its cradle spindle area. Bob mentioned helms link to the swing arm itself tied to frame. That'd be a feat to ponder.

Peels set up ties both rear frame loops together and also the rear cradle plates to combine stiffness to resist chassis twist, yet I can feel chassis twist up, but so far never rebound but in one smooth predicable delicious release out of apex hardest at the point of least traction, flabbergasting impossible sensation to me.

hobot