Isolastic Conversion Kit

soren · Jan 3, 2010

Hi everybody out there
I am wondering, am i a total idiot or what is wrong. I am rebuilding my 1971 Commando, i got far with assembling the bike, but now i have dismantled it again, why ?
Because i discovered a problem with the isolastic mountings. I will try to explain: As i hope You can see at the attached pictures, the gap between the tube and the axle in the LH side is too much. The axle is 12,62mm and the tube is 14,62mm. The abutment on RH side has same hole size as the axle, but the adjuster at the LH side goes outside the tube and therefore too large, what is the problem ?
Best from a cold, cold Denmark
Soren

mcns · Jan 3, 2010

There is no problem. I to thought the same when I called Les Emery and asked him why that was, he said thats they way it works, and it does.
The only thing I didnt like was the harder style rubbers that came with it, so I just opened to 15 thou and its pretty good there, when take my hands of the bars at 70mph my 71 rides straight as pin.

cheers

soren · Jan 3, 2010

Thankyou, but i really can`t understand, why is it in that way, then i will also have trouble with my centerstand, but if You say so i will try fit the whole again

Best Soren

mcns · Jan 3, 2010

The way les explained it to me is when you torque to your 25 foot lbs it centers itself.
That is your back iso, you will notice on front the gap will be on the opposite side.
What I dont understand is why your centerstand wont work?

Best from a hot,hot arizona

cheers

Ron L · Jan 3, 2010

So the entire force of the motion of the power unit will be tranmitted to the stud only at the threaded adjusters? It would seem this would cause the tube to flex the 2 mm and possibly cause fatigue and failure at some point.

I just checked three vernier Iso mounts I have on the shelf, and they all are a snug sliding fit on the stud, so this must be a trait of Les Emery's stock. To me, this would not be acceptable.

ludwig · Jan 3, 2010

I am with Ron L .
this is unacceptable .
I would remove a few mm of the threaded tube and make a press in bush with top hat to centre the bolt and spread the load over a larger surface .
For the bush , I would use stainless steel for hardness .
(and I am not too surprised LE sells stuff like this )

bsaboss · Jan 3, 2010

I've just checked an original rear Mk3 isolastic and a pair of new replacements (front and rear) and in all three the mounting bolt is a nice sliding fit through the centre of the isolastic mount. I'd send them back and buy correctly made ones from someone else, or else make up a sleeve as has been suggested.

daveh · Jan 3, 2010

Soren — I cannot see the photos you have posted but as I understand it, the engine bolt is a sloppy fit in the inner part of the isolastic tube. This is indeed unacceptable and you are right to have your doubts. I had the same problem with a new isolastic mount from Norvil. Instead of sending it back and having to wait for at least two weeks, I made a steel tube that is a light press fit in the isolastic tube. The internal diameter is now reduced, and the engine bolt is a snug sliding fit. If you have a lathe or have access to some suitable tubing, you could do the same. Otherwise, send it back to Les Emery.

lynxnsu · Jan 4, 2010

I run 3 isolastics on mine and I spaced them all out with shims between the adjusters and the frame .I cannot remember how the original mk3 worked or better how it was fitted but if you think about the way the old system worked with large shims between the cups (read adjusters ) and the cradle , that had NO gap between caps (yes ....adjusters ) and frame
btw Les Emery is to be avoided like the pla.... (read dirty disease )so I would not rate his mechanical expertise very high(he used to have pete lovell for that and that was a nice bloke (as in not a rip-off)

rustynuts · Jan 4, 2010

I would agree too. Knowing what I have learnt over the years, I would only buy modification parts from people like Mick Hemmings and Norman White. They have both been developing and building successful race machines for the best part of 40 years and know a thing or two about what falls apart after a long thrashing and what doesn't.

I have the Hemmings vernier isolastic conversion. It is well made, easy to fit and unsurprisingly doesn't have any large gaps where there shouldn't be any!

Seeley920 · Jan 4, 2010

I agree totally, I've been saying it for years, if you want good quality parts avoid Les Emery for all you're worth. Mick Hemmings, Norman White or Steve Maney. Althouigh I haven't dealt with them for a while, RGM used to be OK too.

mcns · Jan 5, 2010

So i guessed I learned something from this thread, next time I have some time I will be making up some bushes for these.
I also noticed on les emery norvil head steady thay the stud is a loose fit. Does anybody know why he would do this, or is he on crack?

cheers

soren · Jan 6, 2010

Hi folks
Thankyou for all your replies, i have learned a lot. I have today bought a set from another manufakturer and it fits fine.
I will returns the others and hope to have my mony back :twisted:
Best Soren

Andy · Jan 6, 2010

Sören, so you are happy in the end!

Will you let us know where you bought it? What did you pay, how much was shipping to Denmark, whome can you recommend?
I plan to convert my 72 Roadster as well.

Cheers,
Andy

nortonspeed · Jan 6, 2010

Seeley920 said:
I agree totally, I've been saying it for years, if you want good quality parts avoid Les Emery for all you're worth. Mick Hemmings, Norman White or Steve Maney. Althouigh I haven't dealt with them for a while, RGM used to be OK too.

In my opinion Les Emery is not to blame selling this 'genuine Andover Norton parts' MK3 iso.rubber. Because of this topic I checked my recently bought MK3 isolastic rubber to find out it's no good either. Mind you it came all sealed in plastic including 'genuine Andover parts ticket and number'. So Andover is selling this inferior part itself :shock:
I am very frustrated by the lousy quality of so called 'genuine Norton parts'. Half of my newly bought parts I have to reshape to obtain a satisfactory fit. It's a fucking shame :!: :!:

daveh · Jan 6, 2010

nortonspeed said:
I am very frustrated by the lousy quality of so called 'genuine Norton parts'. Half of my newly bought parts I have to reshape to obtain a satisfactory fit.

Nortonspeed — I support you on that. And it's not just the fit, it's also the finish. Apart from the sloppy isolastic mount, I bought a new "Genuine" tacho cable and the plated ferrules began to rust within a matter of weeks, and the plating on a new rear brake stay and bush was poor as well. Not all Genuine Parts are like this, of course, but I am sure many of us have been disappointed and frustrated with their poor quality. It's about time we did something about it. If people don't say anything, the makers and suppliers won't get the message and there will be more disappointed customers. I don't believe the occasional individual complaint will be enough to make them improve. Ideas, anyone?

bpatton · Jan 6, 2010

I put a set of MkIII iso's on my '73 and eventually replaced them with Mick Hemmings adjusters. I too sleeved the inside of the tube. But what got to me about the MkIII's is that the tube is very thin and it will crush when you tighten down the nuts. If you don't use a torquewrench every time you button it up you'll get a different clearance. The metal tubes on the earlier buffers and rubbers are very stout and fit the stud/bolt well. By design the Hemmings iso's are adjusted with the nuts tight in place and they use the old style rubber stuff, which may be softer? Besides, it's a nice design, Mick Hemmings is an all around good guy, and Brian Tyree gets a couple bucks in royalties. Always slather the rubber parts with silicone grease so the mount/cradle will center itself and the the rubber won't glue itself to the outer tube, quite so fast.

mcns · Jan 6, 2010

So is it just me or are the humans who make these isos with sloppy fittings incabable of setting up a lathe properly, or just plain FUCKIN LAZY.

from now on all my parts will be coming from north america, NEVER AGAIN

cheers

kommando · Jan 7, 2010

Proably lazy in buying in the tube and just using nearest metric size is my guess.

soren · Jan 7, 2010

Hi Andy
Sorry i cant` tell You because, i was frustreted and in bad mood, so i went to the lokal dealer here and it was not cheap.
And just in a plastic bag without any label, so i dont know. It was not Andover part. But i could come further on with my project.
Best Soren

Isolastic Conversion Kit

soren

mcns

soren

mcns

Ron L

ludwig

bsaboss

daveh

lynxnsu

rustynuts

Seeley920

mcns

soren

Andy

nortonspeed

Guest

daveh

bpatton

mcns

kommando

soren

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