Welcome to the Access Norton Forum. Login as a VIP member to remove the advertising banners.


Isolastic Conversion Kit

Classic Norton Commando Motorcycles.

Isolastic Conversion Kit

Postby soren » Sun Jan 03, 2010 10:22 am

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

Image

Image

Image
Ariel 1929
Nimbus 1937
Nimbus 1938
Nimbus 1942
Nimbus 1946
Nimbus 1953
BSA 1958 Tr
Norton Commando 1970
Triump Bonneville 1978
Triumph Daytona 1999
Aprilia Moto 6.5 1999
Aprilia Moto 6.5 2000
Triumph Sprint ST 2003
Triumph Thruxton 2007
Triumph Tiger 2009

soren
Posts: 9
Joined: Tue Dec 29, 2009 11:44 am
Location: Denmark

Re: Isolastic Conversion Kit

Postby mcns » Sun Jan 03, 2010 10:41 am

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

mcns
Posts: 114
Joined: Wed Feb 20, 2008 7:08 am

Re: Isolastic Conversion Kit

Postby soren » Sun Jan 03, 2010 12:57 pm

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
Ariel 1929
Nimbus 1937
Nimbus 1938
Nimbus 1942
Nimbus 1946
Nimbus 1953
BSA 1958 Tr
Norton Commando 1970
Triump Bonneville 1978
Triumph Daytona 1999
Aprilia Moto 6.5 1999
Aprilia Moto 6.5 2000
Triumph Sprint ST 2003
Triumph Thruxton 2007
Triumph Tiger 2009

soren
Posts: 9
Joined: Tue Dec 29, 2009 11:44 am
Location: Denmark

Re: Isolastic Conversion Kit

Postby mcns » Sun Jan 03, 2010 2:58 pm

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

mcns
Posts: 114
Joined: Wed Feb 20, 2008 7:08 am

Re: Isolastic Conversion Kit

Postby Ron L » Sun Jan 03, 2010 3:21 pm

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.
Ron L
'73 MkV 750 Roadster
'74 850 Interstate
P11's
some Nortons in boxes
Access Norton VIP Paying Member
Ron L
VIP MEMBER
Posts: 2555
View Photo Album - Images: 1
Joined: Fri Feb 27, 2004 5:37 am
Location: Ohio

Re: Isolastic Conversion Kit

Postby ludwig » Sun Jan 03, 2010 3:41 pm

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 )
Si tous les dégoûtés s'en vont , il n'y a que les dégoûtants qui restent ..

ludwig
Posts: 1818
Joined: Wed Aug 30, 2006 3:57 am

Re: Isolastic Conversion Kit

Postby bsaboss » Sun Jan 03, 2010 4:19 pm

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.

bsaboss
Posts: 66
Joined: Fri Sep 11, 2009 10:49 pm

Re: Isolastic Conversion Kit

Postby daveh » Sun Jan 03, 2010 6:42 pm

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.

daveh
Posts: 905
Joined: Tue Jan 22, 2008 5:03 pm
Location: Dublin, Ireland

Re: Isolastic Conversion Kit

Postby lynxnsu » Mon Jan 04, 2010 12:58 pm

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)
User avatar

lynxnsu
Posts: 318
Joined: Tue Sep 18, 2007 5:03 am
Location: flanders

Re: Isolastic Conversion Kit

Postby rustynuts » Mon Jan 04, 2010 3:16 pm

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!

rustynuts
Posts: 9
Joined: Wed Nov 18, 2009 4:51 pm

Re: Isolastic Conversion Kit

Postby Seeley920 » Mon Jan 04, 2010 3:24 pm

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.
Ridden, not polished!

Seeley920
Posts: 493
Joined: Tue Jan 06, 2009 5:58 am
Location: Beds. UK

Re: Isolastic Conversion Kit

Postby mcns » Tue Jan 05, 2010 7:21 pm

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

mcns
Posts: 114
Joined: Wed Feb 20, 2008 7:08 am

Re: Isolastic Conversion Kit

Postby soren » Wed Jan 06, 2010 1:04 pm

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
Ariel 1929
Nimbus 1937
Nimbus 1938
Nimbus 1942
Nimbus 1946
Nimbus 1953
BSA 1958 Tr
Norton Commando 1970
Triump Bonneville 1978
Triumph Daytona 1999
Aprilia Moto 6.5 1999
Aprilia Moto 6.5 2000
Triumph Sprint ST 2003
Triumph Thruxton 2007
Triumph Tiger 2009

soren
Posts: 9
Joined: Tue Dec 29, 2009 11:44 am
Location: Denmark

Re: Isolastic Conversion Kit

Postby Andy » Wed Jan 06, 2010 1:29 pm

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
60 A10
72 750 Commando
75 850 Commando
79 850T3
81 XT500
84 ETZ250
93 R100GS
00 Thunderbird Sport
User avatar

Andy
Posts: 50
Joined: Tue Apr 14, 2009 4:34 am
Location: Germany

Re: Isolastic Conversion Kit

Postby nortonspeed » Wed Jan 06, 2010 2:44 pm

Seeley920 wrote: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 :!: :!:
User avatar

nortonspeed
Posts: 591
Joined: Sun Jun 29, 2008 6:50 am

Next

Return to Norton Commando Classic Motorcycles

Who is online

Users browsing this forum: ashman, Bing [Bot], jaydee75 and 4 guests