Another solution to the commando wiggle

I was talking to buddy down the road from me that builds triumph choppers and cafes. He likes to get rid of his remaining Norton parts (and knowledge). Anyway he was telling me about how he used to fix the commando handling problems. He would cut the rear iso tube off a donor cradle, notch the bottom rear of the cradle, under the swingarm and weld the spare Iso tube into the cradle; along with tabs on the frame to bolt it to. Shim it up like the others and you are goo to go.

I am wondering if anyone around here has tried it or seen it done. Pics would be great!

I have half a inclination to try it out next time I have my bike in pieces.

Cheers

John

Clever place for extra isolastic which don't bounce like the front to convey vibes. By far I found stabilizing the rear cradle against swing arm wagging it give best bang for the handling bux vs head or breast stays.

Would be curious if you describes what upsets you about Commando handling.

You mean a third iso? Like the VR880?

Ha I have gotten used to it, lose is fast right? It did take working up to it tho, learning the capabilities of the bike and gaining confidence on my part. I learned to ride on a cdo, been on plenty 2 wheeled toys and horses so it wasnt a huge learning curve. The advice from the old timers helped a bunch, go in Fast, brake hard, be sure to be in the right gear Before the corner then load her up and hang on.

I make my buds on gixers and R6s real nervous in the corners, but they aren't racers and would have a cow if their shinny plastic bikes were ever laid down. I look at it as part of the learning experience.

-john

swooshdave said:

You mean a third iso? Like the VR880?

Click to expand...

It would be such. I guess I should take a closer look at the 880, that didn't come to mind talking about it. It has been awhile since I last took a close look at one.

here is an alternative solution to the dreaded commando wiggle. seems to work ok

Dreer put his extra isolastic mid way under the frame. In general more rubber bearing area = less isolation.
That triangulated brace with all 3 rod eye's aligned the same way is a new one on me. I'm not sure I understand what I'm seeing, at least in regards to how the rods eyes on shafts work to resist sideways loads yet not transmit vibes.

Appreciate hearing John's cycle handling summary. I never had a cycle that turned by leaning before my 1st Combat and got 1st taste of hinged surprise a few weeks owning it having fun chasing with a 1100 in fairly short length turns or fairly mild ones up to 90 till we got to a long 270' sweeper marked 35 mph entered at 70 and tried to keep up into 80's for a flopping fish off deck scare. There was some wavy surface about mid way and that's all it took to upset the Combat but not the modern. Later I found wind gusts can upset Cdo hinging in long held sweepers. Its takes a bit of time it seems for resonance to build up though i've since learned a handful of other ways to onset hinged horrors below speed limits, flat tires and zig zags mainly. I took that insight with me to press moderns into their hinged zone too, they all will do it but moderns hit harder at faster speeds and freq its harder to predict and recover, but faster than un-tamed Cdo before it does.

The way Peel is tri-linked I have not been able to upset her in any way going in way faster and held lower longer than I can on modern like SV650 or Ninja and a whole bunch of other sports bikers trying to prove how obsolete my Combat was. The new boxed swing arm on Peel allows for bracing its side loads on back of Zplate with swash pads. The trouble with such secure neutral handling is it invites you into ridiculous rates as such low effort to control but there is a point where both tires can not stay in such loads, then slides begin or new ways of handling faster turns developed. Also you tend to run up the butts of traffic and cops around blind bends and braking while leaned sucks.

This brings me to mystery of if there's a state of being too rigid vs too flexy. Is there a happy compromise? I think there is in the isolastic Commando with its little helpers.

Seen one on ( under ! ) a Black 850 at Pukekohe the year Williams was there , pointed out by the owner , in fact .
TT100s on it , Says he lives miles up a dirt ( gravel ) road , and it doesnt mind it at all .

Looking at the rear area of the frame ( rear Iso Mt. ) its somewhat ' Triangulated 'so should have good longitudeinal &
Torsional Ridgidity there . This Guys was up under ( behind I guess ) the gearbox.Not protudeing down obviously .

SO , . . . If ' We ' absorb the torsional / longitudeinal ' Twist ' here , rather than through the head steady , it puts the
whole load distribution / Load Path equation into a new ballpark . Leaveing the front to primarilly laterally locate the
transverse drivertrrain forces, and has the head steady on a picnic/ supurflous .

TRIANGULATION being , rather than a widely dispersed ' three points ' with the side loads transfered , and ACTING
( see head steady ) there , the torsion is absorbed at the rear triangulation .Leaveing the big long spine tube for
torsional forces from the ( front ) suspension .

Yes indeed , so , If your Commando , at times , has the disposition of a long beam , through axles ( Forward through
rear axle , Trans and Crankshafts , and front axle ) in the manner of stability or feedback , this contraption will
secure all the loads down there , so as the steering head rock , or side shake , is scarcely relevant to Line Holding ,
even on irregular surfaces . ( Almost as good as a 61 Bonne on the Dirt . :lol: 8) )

Id think it adviseable to keep it well aft , for the reasons mentioned . AND shim em all at 2 to 4 thou. centered .

swooshdave said:

You mean a third iso? Like the VR880?

Click to expand...

Any photos of the VR880 set up?

peter nelson said:

here is an alternative solution to the dreaded commando wiggle. seems to work ok

Click to expand...

Looks to be allowed to slide a limited amount sideways on the p/bronze brushes-am I correct?

I'd like to see a side plane drawing showing the swinging arc of the cradle at that attachment point.

The construction of this solution would have to allow for that exact arc for the system to be correct.

Otherwise, as the cradle attempts to rotate from the engine's vibration, it's being forced around an irregular path at that rear point, which would result in some significant stresses on all the other isos, and wierdness in the swingarm's forced path.

UNLESS you remove the top steady, as Kenny Dreer did. Triangular is so much easier than quadrilateral.

At this point i-me-myself think/feel/find Ms Peel Watt's like linkage is the best solution, one rod below cradle and one rod above cradle so up/dn motion puts them in conflicting bind to hold cradle in vertical plane and distance between them front to back tames the rear patch levering through rear iso to slap the front mount silly side to side which in turn slaps the forks to oscillate then self magnify into hinged handling horror. This interlocks the power unit with the frame like over lapping intertwined forks. I found mainly the rear rod stopped the weave upset but still felt front tire following road texture wobble annoyance but front link eliminated that. Then could only feel the wind gust eddies off fork tubes and headlight, then top 3rd link eliminated even that mild sense of a loosely constructed sloppy light bike in the breeze sense for huge massive inertial stability sense like an over loaded Goldwing. Uncanny beyond belief!

There is some danger to Peel's set up as there is NO UPSET WHAT SO EVER NO MATTER HOW FAST AND LOW YOU THROW HER OR HOLD HER DOWN IN ANY TURN so there is NO NEED TO SLOW DOWN OR REDUCE POWER in any turn WHICH THEN PRESENTS IN YOUR FACE HAZARDS IN BLINDS that require handling antics beyond phase two steering that keeps both tires or even one tire on the surface, but then while air borne the bike flys off at a tangent and acceleration of water skiier hard pull on wrists fantastic high- disapears and vibes like crazy till landing again. Bike also twists in mid air on it/pilot's CoG like it does on THE Gravel so the extra sharp turning radius just temps one into turning every turn into faster accelerating decreasing radius wonder land. If ya are thinking flat tracker style wide lazy crossed up tire spin turns then you are totally missing the wild tunnel hull sharp boat turning ability, but w/o any sense of wave and wake roughness.
Closest sensation to Ms Peel I've got is slalom water skiing on mirror smooth water in narrows the trees over hang from both sides. There is not enough traction in snow skiing to hook up edges to compare the G's developed.

Maybe other better ways to tame a Commando but OH MY GOD I sure couldn't stand to find out and still don't know how much harsher Peel can take it d/t the dangers in public blinds to find out. The main effort to ride Peel like this is breath control and eye focus muscles on the zooming things straight ahead until the last instant. Flabbergasting Fabulous !

peter nelson said:

here is an alternative solution to the dreaded commando wiggle. seems to work ok

Click to expand...

That is clever, it would also be the perfect solution for a featherlastic. The for-aft length should be long enough that it wont make much difference to the ISO rubbers.

grandpaul said:

I'd like to see a side plane drawing showing the swinging arc of the cradle at that attachment point.

The construction of this solution would have to allow for that exact arc for the system to be correct.

Otherwise, as the cradle attempts to rotate from the engine's vibration, it's being forced around an irregular path at that rear point, which would result in some significant stresses on all the other isos, and wierdness in the swingarm's forced path.

UNLESS you remove the top steady, as Kenny Dreer did. Triangular is so much easier than quadrilateral.

Click to expand...

Well stated. Brings us back to the teflon/poly pad sliding system.

The late oil guy Gerry Bristow gave me his teflon swash plate top steady, because it transmitted buzz. Its 1.5"pucks on under tube and two similar pucks on head with adjustable spacing. It has witness marks to back up my front iso motion witness marks. I've not installed it as tried top rod link first and found it isolated fine if left slack adjusted.

I've put on at least 1000 miles on factory Trixie w/o head steady to get very unpleasant upset on first crossing of double yellow in a clear sight turn, but after I realized how dangerous factory iso's are w/o the 3rd helper, I just backed off to normal fast riding w/o an issue. On new tires I have no problem to keep up with Wes in a huff > unless leaned over on broken/wavy injured frost heaved surface. Then I'd crash at the surprise horror at speed, just glad I discovered the limit ahead of time as it took 20 miles of riding and forgetting about missing head steady completely to get alerted. So unless taking chances on holding leans at illegal speeds on rough or windy conditions I doubt anyone would notice head steady missing. Its not needed at all on Peel with 2 cradle links but for the wind fork jiggles and mild road texture fork twitch removal.

Gerry's head steady, essentially ready to install, is offered for cost to ship for others to experiment with and get back to us.

Just to update this thread - my high speed weave went away when I wore out my fat Avon and went to one a bit narrower.

Hi, a mate and fellow C'do owner had several bikes starting in the '70's and still owns an 850 now.
As a frequent rider and over big miles ,and a fitter machinist, he recognized the problem early, and installed a permanent web between the plates , similar in size to the welded swingarm spindle. handles perfect.
He has one still in his current bike, so will get a pic and post for you
Regards Mike

here is a pic of one
this is the difficult way , some (like ludwig) have done it easier and with the same results , only without the drawbacks , like the adjustments
it consists of an ertalon block , fixed to the frame , but adjustable to just rub on the cradle
easy and it works

Does this increase the rpm of isolation?

as i set mine rather tight it does vibrate more , low and high rpm
however the bike is ridden over longer distances (550 km a day secundary roads ) so it is not breaking me to bits
Ludwigs bike is ridden over longer distances but his isos are not that tigfht i believe (should ask that himself )
mine is build to blow off japs , so 500km is enough , any more and i will be blown of the bike . it did weave before the mod so it does work