Hard vs Soft Isolastic Rubber (2009)

[dynodave]

IIRC the "Hemmings" adjusters originated from a fellow in SW USA. How they came into Mick's posession was not explained or brought up as unscruplous. He may have bought the design and the rights to patent it.
I like that concept and would probably buy a set to try out. I don't seem to need to adjust the shims much on my commandos since I use them more as a touring bike rather than a ricky racer canyon carver.

 

[swooshdave]

IIRC the "Hemmings" adjusters originated from a fellow in SW USA. How they came into Mick's posession was not explained or brought up as unscruplous. He may have bought the design and the rights to patent it.
I like that concept and would probably buy a set to try out. I don't seem to need to adjust the shims much on my commandos since I use them more as a touring bike rather than a ricky racer canyon carver.

How could you patent them? They are just the MkIII verniers but a quarter inch longer, no?

 

[bsaboss]

Does anyone have recent experience of fitting the (new, softer) AN Mk3 rubbers, and if so did they smooth out at 2000rpm as DD suggests the originals did/do? The other issue that I have read about (and experienced) with some aftermarket sets is the internal diameter of the steel tube is too big and they are a very loose fit on the mounting bolt. Hopefully the AN ones are a nice slide fit on the mounting bolt?

 

[850commando]

Would that be the Norvil ones made with some off the shelf std metric tube that fits where they touch which is no where.

yeah that norvil.

yes i know that AN provides these as factory items. My point is that a certain supplier was substituting Norvil parts for the AN which was not discovered until after they were installed and vibrated at all rpm.

 

[DogT]

I don't think the 'Hemmings' adjusters are the MkII type. I remember going over all this stuff years ago and decided there were at least 3 or 4 types of verniers, the 'Hemmings', the MKII, the Norvil and maybe even the 850 style. The 'Hemmings' adjusters replace the original 69/70 end caps with an adjustable one. As to who made the 'Hemmings' adjusters I remember reading about it but never came to a conclusion, I only know I bought them from Angie and there was no issue installing them.

As far as the donuts, I remember there were 4 that went into the front adjusters and 2 of them were tight and 2 of them didn't even touch anything except the center tube. The also just floated in there being held in with some clips.

 

[850commando]

How could you patent them? They are just the MkIII verniers but a quarter inch longer, no?

quote"
A little interesting history to add to the mix:

In the early 90s, while on a ride back home from a Four Corners Norton Rally here in the southwest USA, Brian Tyree of New Mexico was loping along the highway musing about isolastics.

He thought to himself, self couldn't I go home and machine a set of threaded adjustors?

He did so, got a US patent, and went to England to meet with Mick Hemmings to handle the marketing.

Now, I live in Albuquerque along with Brian, and this is the story he told me many years ago.

The first sets of threaded adjusters had a nylon tip on the securing allen bolt, and this could randomly tighten down right on the leading edge of a thread, thus sheering off the nylon, and of course being on the thread's edge have little holding power.

When I talked to Brian about wanting a set back then he told me he did not make them and I would need to order from Hemmings. When i got my set way back then, the isos kept tightening to no clearance because of the above.

I mentioned this to Heinz Kegler and Heinz and I removed my threaded isos and Heinz milled off a couple of unneeded threads, creating a flat spot for the allen bolt to come down on securely. Heinz also felt the holes and the allen bolts were a little too small so he bored out my iso holes and put in larger allens to bear on the newly milled flat spots, thus eliminating the need for the nylon tips. Problem solved, now when set the allen bolts the isos do not move, can't loosen or tighten.

I have no idea if these improvement of Heinz's have been incorporated into the threaded isos you guys are buying nowadays. But if not, that is the solution.

Just a little history for your idle reading!"

John Schmidt

 

[swooshdave]

quote"
A little interesting history to add to the mix:

In the early 90s, while on a ride back home from a Four Corners Norton Rally here in the southwest USA, Brian Tyree of New Mexico was loping along the highway musing about isolastics.

He thought to himself, self couldn't I go home and machine a set of threaded adjustors?

He did so, got a US patent, and went to England to meet with Mick Hemmings to handle the marketing.

Now, I live in Albuquerque along with Brian, and this is the story he told me many years ago.

The first sets of threaded adjusters had a nylon tip on the securing allen bolt, and this could randomly tighten down right on the leading edge of a thread, thus sheering off the nylon, and of course being on the thread's edge have little holding power.

When I talked to Brian about wanting a set back then he told me he did not make them and I would need to order from Hemmings. When i got my set way back then, the isos kept tightening to no clearance because of the above.

I mentioned this to Heinz Kegler and Heinz and I removed my threaded isos and Heinz milled off a couple of unneeded threads, creating a flat spot for the allen bolt to come down on securely. Heinz also felt the holes and the allen bolts were a little too small so he bored out my iso holes and put in larger allens to bear on the newly milled flat spots, thus eliminating the need for the nylon tips. Problem solved, now when set the allen bolts the isos do not move, can't loosen or tighten.

I have no idea if these improvement of Heinz's have been incorporated into the threaded isos you guys are buying nowadays. But if not, that is the solution.

Just a little history for your idle reading!"

John Schmidt

This should answer your question.

 

[dynodave]

How could you patent them? They are just the MkIII verniers but a quarter inch longer, no?

NO
Look in any pre MKIII parts book.
Seems you're not familiar with what you are talking about. The "Hemmings" adjusters are to replace ONLY the front engine mount collar/front engine mount tube cap holders on the early/pre MKIII isos. Repeat for the rear.
The other common upgrade (IMO garbage) is the single piece tube with molded rubbers AKA MKIII style...this is NOT the "Hemmings" type.

This should answer your question.[/QUOTE]

I'd be willing to measure the rubber compression rate. Only then would I even consider trying the MKIII type on a pre MKIII bike.
However this video is still NOT showing a Hemmings/Tyree unit for use on individual component ISO's.

Does anyone have recent experience of fitting the (new, softer) AN Mk3 rubbers, and if so did they smooth out at 2000rpm as DD suggests the originals did/do?

Please reread my post.
DD has NOT made any claim about any MKIII style iso's. My original MKIII vibrates horribly compared to my unmodified original combat.

 

[dynodave]

snip
As far as the donuts, I remember there were 4 that went into the front adjusters and 2 of them were tight and 2 of them didn't even touch anything except the center tube. The also just floated in there being held in with some clips.

In the front ISO, the big rubbers are the main carriers of the load. The smaller buffers are for when you overload the bike with either a pack horse camping load( fat chick) or you over stress the drive train with such as a hole shot. Only then is when the secondary buffer come into play by increasing the compression rate. The approximate 50% commando balance factor keeps the engine vibes from banging the buffers during normal cruising.

 

[dynodave]

Some light on my terminology?

MKIII iso = molded rubbers on a pipe/tubing without respect to shims or vernier adjustment.
Original 75 norton was with vernier adjustments and rubber stick was quit stiff and vibrated a lot.

Vernier = threaded/screw type clearance adjusters, adjustment locked with set screws.

Hemmings/Tyree = vernier short for original/early discreet component ISO's.

Aftermarket vernier MKIII style = bad and good quality (if possible) for earlier (pre MKIII) bikes.

 

[Onder]

So if I have the adjustable ends ( I got them from Mick) Can use the current AN one piece rubbers and tube
06.6126 ? This is the MkIII piece but they offer the kit for all Commandos which seems to use it.
The heart of the question is: which set up gives least vibration?

 

[DogT]

The Hemmings adjusters I got have the small grub screws (Allen screws on this side) with the nylon tips. There are no flats to bear on. I haven't had any issues with mine, but I only have about 2K on them. I thought they looked a bit sparse for what they did and thought drilling out a few for a larger Allen screw would be a good idea. I'd heard that before.

I though the Hemmings adjusters would fit on any model, but I've been wrong before. All it does is make the collar to frame distance adjustable. They were dead simple to install, just replace one collar. One on the front and one on the rear.

I thought maybe what DD says about the 2 loose donuts in the front was probably what was going on. There was no other reason they'd be like that. The ones I took out were molded to the tube, there were no clips holding things in place. Kinda ruined them getting them out. I still say they are softer than what I replaced them with although the design was essentially the same.

 

[elefantrider]

Your problems were that the verniers are a bad design it’s that you got them from the wrong supplier.

And no, not all of them are the same. Never make that assumption.

That was not my problem with it. Read again.

I was talking about how they don't really offer any advantages for me over the MK1 shim system.

I bought mine 25 years ago before AN had a a kit or anyone even had an internet site.

MK1 shim systems are a little lighter, and use independent rubbers. Pull out one bolt and the mount is completely free. Faster and easier to R&R and align.

At the time, I remember the guys pushing Vernier mount conversions said you could adjust them tight for twisty roads, and then loosen for cruising the highway.

But how many people actually do that??

Not me.

 

[L.A.B.]

So if I have the adjustable ends ( I got them from Mick) Can use the current AM one piece rubbers and tube
06.6126 ?

No, not unless the adjuster end of the tube was cut/machined off (or both ends unless the Mk3 threaded 'fixed abutment' is used) as the Hemmings adjusters have threaded sleeves that replace one Edit: collar whereas the threaded section is an extension of the 'tube' on the factory Mk3 (and pre-Mk3) Vernier conversion kit.
Hemmings kit (front and rear, rear on the left):

 

[swooshdave]

No, not unless the adjuster end of the tube was cut/machined off (or both ends unless the Mk3 threaded 'fixed abutment' is used) as the Hemmings adjusters have threaded sleeves that replace one Edit: collar whereas the threaded section is an extension of the 'tube' on the factory Mk3 (and pre-Mk3) Vernier conversion kit.
Hemmings kit (front and rear, rear on the left):

Thank you for actual pictures instead of chastising.

 

[TopgunPeter]

I assume the kit from RGM wasn’t from Andover?

It was embossed with RGM.

 

[TopgunPeter]

I've just restored a '72 Combat and fitted a new front Vernier from RGM and found it vibrated far more than I would expect. I've had to 'tinker' with the mounting a lot and have ended up with going back to some old, soft rubbers I had using pre-Vernier and this is now a lot smoother. One thing that has occured to me, in all my 'tinkering' is that the pre-Vernier is not so bad to adjust side clearance and not much worse than Vernier. The great advantage of pre-Vernier is that it is SO MUCH easier to remove and replace the whole unit on the bike. Removing and replacing an Iso unit with Vernier is VERY difficult and can only be done by force which 'flexes' the frame tubes, which is worrying. The other disadvantage of Vernier is that you can only adjust the side clearance on the vernier adjuster side.

Addendum: I still wasn't happy with vibration and was getting a 'tingling' through footrests and bars so started looking at rear isolastics and found from the invoice that RGM had sent me a new set described as 'HEAVY DUTY' which is the only set they sell. I decided to look at the rubbers again, which is not easy, and found these 'HEAVY DUTY' ones to be very hard indeed and it was clear they were the source of the vibration. I managed to get the two outer ones and the buffers out using a long threaded stud and replaced them with old soft ones. A test ride showed that the bike is beautifully smooth now just as I would expect of a Commando.
I'm now puzzled as to why such hard rubbers are sold because I can't see any advantage in them other than a tickover with less 'shake'.
This has all been very time consuming but I can now get back to fixing the oil leaks !

 

[850commando]

Addendum: I still wasn't happy with vibration and was getting a 'tingling' through footrests and bars so started looking at rear isolastics and found from the invoice that RGM had sent me a new set described as 'HEAVY DUTY' which is the only set they sell. I decided to look at the rubbers again, which is not easy, and found these 'HEAVY DUTY' ones to be very hard indeed and it was clear they were the source of the vibration. I managed to get the two outer ones and the buffers out using a long threaded stud and replaced them with old soft ones. A test ride showed that the bike is beautifully smooth now just as I would expect of a Commando.
I'm now puzzled as to why such hard rubbers are sold because I can't see any advantage in them other than a tickover with less 'shake'.

maybe RGM felt that a market existed for the harder iso's. i am inclined to think that they Or their supplier) did a poor job or reverse engineering the rubber durometer and delivered the hard iso's. ( if they buy from Les E. then i think therein lies the source of the offspec product)...

 

[kommando]

The Norvil ones are hard and moulded onto an oversized tube so are the worst (no surprise).

RGM were hard on the correct tubes but may not be hard now as RGM say they have gone softer but how soft.

Andover Norton current ones seem to be the better option hardness wise as recommended by Norman White but watch out for old stock as even Andover made too hard ones in the past. I have some current Andover Norton rubbers and they are slightly harder than a set of NOS MK3 never fitted, so scope for them to be even softer.

But if you have old soft ones pre vernier in good condition then get the Hemmings adjusters and use them, if they have developed a set to one side turn them round 180 degrees.

 

[swooshdave]

But if you have old soft ones pre vernier in good condition then get the Hemmings adjusters and use them, if they have developed a set to one side turn them round 180 degrees.

You might want to try 90 degrees.