Isolastic solution and handling improvement

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Here's the idea:

A Commando owner got tired of the isolastic "hinge in the middle" feeling. He removed his isolastics and filled the cavities with a liquid compound that solidified into solid rubber. This stuff is available from industrial suppliers and comes in various hardness’s. The bike handled noticeably better and there was some increased vibration because of the firmer rubber. The cast in rubber is more or less permanent and side slop is pretty much eliminated (no more adjusting & replacing isolastics). I can't say which hardness it was from memory but I think it was polyurathane and came from here:
http://www.bjbenterprises.com/

Now - suppose you did the same thing and added my lightweight pistons & longer rods to take care of the vibration. (Go to http://www.jsmotosport.com)

You would have the best of both worlds - better handling and a smooth ride. There would still be some vibration dampening to protect the frame because there would still be some rubber (albeit firmer) to isolate the motor. For everything to work you would have to make sure your swing arm spindle was tight.

So what would be the interest out there? Is anyone willing to pursue this as in “do this to your own Commando”?

Jim
 

grandpaul

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I don't have time to do it to one of my Commandos, but I'll gladly do it to any client's bike that wants it done.
 
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jseng1 said:
Here's the idea:

A Commando owner got tired of the isolastic "hinge in the middle" feeling. He removed his isolastics and filled the cavities with a liquid compound that solidified into solid rubber. This stuff is available from industrial suppliers and comes in various hardness’s. The bike handled noticeably better and there was some increased vibration because of the firmer rubber. The cast in rubber is more or less permanent and side slop is pretty much eliminated (no more adjusting & replacing isolastics).
Jim

Care to provide more detail as the specific compound that was used?
 

click

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swooshdave said:
jseng1 said:
Here's the idea:

A Commando owner got tired of the isolastic "hinge in the middle" feeling. He removed his isolastics and filled the cavities with a liquid compound that solidified into solid rubber. This stuff is available from industrial suppliers and comes in various hardness’s. The bike handled noticeably better and there was some increased vibration because of the firmer rubber. The cast in rubber is more or less permanent and side slop is pretty much eliminated (no more adjusting & replacing isolastics).
Jim

Care to provide more detail as the specific compound that was used?


I'm sure I saw a link to the product earlier but it has now been removed?

Kevin
 
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I got your pistons Jim and soon one of your Norris D+ cams,
but I want nothing to do with anything that still transmits any thing
but pure traction texture to pilot and chassis.
A poured rear isolastic might work a treat to prevent doughnut
sag and may not transmit much up-down front engine vibration
but I'll only run soft or even trimmed thinner front doughnuts thankyou.
Its frustrating reading the ongoing efforts to improve Cdo handling
while allowing frame and teeth roots to endure.
Its so solved with proper linkage Ms Peel's goal is to demo it in spades.
Some chassis are too flexy and others too rigid, one is just right.

BTW what race classes only allow factory frames?

hobot
 
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hobot,

I am fitting some of Jims gear also, namely the piston and rod set up in 9:1 compression for an 850. Can't wait to feel the improvement, what is your take on the lighter reciprocating weight?
Also had a look at the front iso today, I trimmed my front mount, by mistake and was looking to bush it back up. But it looks like I will need to either buy a new engine mount or try and get the std MK111 ends.

Cheers Richard
 

rvich

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I would be willing to try something like this on my basket case rebuild but I am probably two years out.

I watched the video, and have been wondering ever since if I might end up going to the lightweight pistons and rods on the rebuild.

I guess if the gang wants to see results sooner they could donate toward a professional rebuild on my bike to speed things up!

In reference to the rubber compound, I have a packet from 3-M sitting in my office that turns to solid rubber when it is mixed. I got it from the local electrical supply. I will have a look at it and report back.

Russ
 
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hobot said:
Its frustrating reading the ongoing efforts to improve Cdo handling

hobot

And this coming from the man who has screwed, drilled, bent, torched, welded and sometimes ruined parts on a commando to get more power and better handling?
 

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hobot said:
BTW what race classes only allow factory frames?

hobot

As far as AHRMA classes that you might run a Commando in, only Vintage Superbike is restricted to frames from factory production bikes. The Commando would run in Middleweight Superbike, with up to 890 cc allowed, or in Heavyweight if larger. 750 Sportsman calls for "pre-73 production type (period tubing type)", but also allows Trackmaster, Champion, and some Rickman frames. You regularly see Commandos in the Bears class and Battle of Twins classes, but they aren't restricted to the factory production frame.

Ken
 
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Responding collectively to scope of responses.
A few confusing issues over lap and blend in this instant thread.
1. better engine performance and safety with less mass jerking.
2. better pilot and chassis endurance, performance and safety with less vibration.
3. better handling of higher sustained tire loads.

a. factory isolastic Commando should not vibe past 2300 rpm

b. factory isolastic Commando can not sustain corner loads of
more rigid modern or non-isolastic Commando powered cycles.

c. better handling rigid mount Cdo's, can suffer frame fractures and
pilot control errors from the vibration static.
Did we forget how central an issue the reports of smooth operation are on Jim's pistons or offset cranks? The manners of performance delivery Matters!

d. unknown to most but Gravel riders and Road Skier's is that
the chassis-suspension-power pulses-tire hysteria and molecular surface
electrostatic charges go in and out of resonance cycles that
if not damped can escalate in a heart beat to splash out of control.
Most of this is not sensed till maxing out everything, then they
dominate and can hit so fast its hard to know what went wrong first.
Not so on my linked isolastic Commando, everything is separated
into its individual influence with little or no confusing inter-reacting
interferences on resonance. Yum oh yum oh yummy - backing into tights is
easier and more refreshing than legal speed touring but both states give
same smooth isolation from anything that don't matter or
pleases you to feel in spades.

Dilemma is how to tame the 360's oscillations yet not suffer
hinged handling upset dangers.

If an isolastic Commando existed that flat disappears to pilot
and chassis by 2200 rpm and its wimpy factory frame could deform,
take up tire conflicts while storing energy from tire traction, power pulses,
road texture, wind buffet/lift/drop and pilot input fuzziness, along with a lighter low BF flywheel, to become totally neutral, only responding to pilot's single actions to change lean angle or aim, regardless if sliding one or both tires
yet allowing 5-10% tire hook up into>through>out of turns, then >>
there would not be much market for expensive rigid chassis and requirement
of heavier cranks to protect frame and pilot just for a little extra
incremental corner handling. One well placed linkage is all that I need.

Britbiker220, you can search my decades worth of posts and
no where will you ever see me mention mass reduction for
extra handling, just to pick-up falls, drag out of ditches and load
up after break downs Plus to get better acceleration and braking
both in corners and straights. Peel's plan is to embarrass the tires
off world class elites on tracks that even they can't reach 150.
My proven tool of choice is a factory isolastic Commando
with a Watt's like handling tamer and about 3x's torque power.

I can hardly imagine what lighter wheels and full street tires
and fancy shocks with active suspension will be like, but
didn't need any of that to put down more power than
hot moderns once they got near 45' lean, pashaw.

So best wishes repeating same old ideas and attempts to solve Commando
handling issues with poured formed isolastic dampers, extra isolastic vibration
transmitting mounts, rigid ringing chassis, steering dampers and extra flywheel gyroscope.

Hm* Peel might even-could make her iso's slack or firm on demand.
Jim brought up idea to replace rubber doughnuts completely so how would
hobot do it?
Rods can not support engine weight, springs might but what kind?
I've spring suspended my big megaphone when rough riding over whelmed
the small Lords mounts. They should be very progressive in rates.

Don't forget that to get Commandos to go silent in usable range,
rubber mass was removed. So what's expected when more is added?
 
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Can't you get a similar result just by using Mk3 Isos and running them a bit tighter?

Vibration can be tuned by crank balancing. I run 72% on my engine that runs in a featherbed , rigidly mounted. Very little ( by Norton standards) vibration.
 
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Can't you get a similar result just by using Mk3 Isos and running them a bit tighter?
Vibration can be tuned by crank balancing. I run 72% on my engine that runs in a featherbed , rigidly mounted. Very little ( by Norton standards) vibration.

You Had To Pay People In Past to Ride a Tightened up By Even Half of Factory
Isolastic Gap Just To Get a Tad Better Handling. Now can't even pay Police or
Racers to ride em, just a few addicts left racing among their own limited kind.

Featherbed rigid mount-BF report is valuable report to me.
This thread jack boot stomps to the core of my Commando insanity nerves.
If I feel any vibration or sense of a Commando's mechanicals under me
then Ms Peel was fun while she lasted failure to be parted out gone.
If Peel can not get a full gear ratio ahead of bikes between entry
and exits then I'll have to cow tow eating Peel's tires to every doubing
Thomas smirker sneering smearing distracter that warned me.

Yoose guys ain't yet mentioned the joys of the nuances of valve train resonance on pilot golggi tendon and spindle cell nerve stress-strain sensors in processing of connective tissue coordination that monitors and reacts to the tire hysteria and phase changes known as traction, which actually comes in bundles of quantum packets of indeterminacy with probability waves to collapse down at last instant to spike a big bang out of there.

That's me story and sticking to it to the very end.

hobot
 

rvich

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I have been talking to the techs at 3M about this idea. Of their product line the Urethan Windshield Adhesive is the choice for motor mounts. Untested for it, no data on it, they just know it has been used for similar applications with positive results. Here is a link for information:

http://solutions.3m.com/wps/portal/3M/e ... 8HT14PGTgl

It has a Shore A hardness of 50-55. I am still educating myself about Shore A and Shore D (In the past I have only been concerned with Shore Sea). The Scotchcast 2130 that I mentioned in a previous post is a two part urethane with Shore A hardness of 80. I am guessing it is too rigid for this application. I am thinking about getting a tube of the windshield adhesive and mocking up an isolastic mount. I could figure out how to hook it up to the paint shaker or something to test it out.

I have also been wondering about using the stock isolastics and encasing them with something like the above to form a single unit. Why? Because we can!

Russ
 
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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.
 

rvich

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MexicoMike said:
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. 8)
 
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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? ;)
 
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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.

Isolastic solution and handling improvement
 
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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
 
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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!
 
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