Front Iso - strange?

seattle##gs said:
With the motor resting on the iso, the gap at top is smaller than the gap at the bottom so I split the difference.
Click to expand...
Not if you have (as I have) a properly adjusted pair of Mk3 springs on the top iso (Dave Taylor)
If I loosen the through bolt, I can slide it back and forth with my fingers.

...and thinking again, even if you don't have the springs, what you said is not correct.
Downward vertical load will deform the rubbers in the large tube but the iso washers themselves see no vertical load. The gap will be the same top & bottom - unless you have something else going wrong.
 
Have reassembled and done a forty mile ride and am happy with the result!

I should mention how I have stopped a recurrence (for other's sake)
I noticed the the left hand "abutment" (the outer "nut" on the left) had an empty threaded hole for a grub screw.
I also noted the outer 6mm of the inner iso tube was not threaded. https://andover-norton.co.uk/en/shop-details-2/16710/isolastic-rubber-front-mounting
So, noting the position of the grub screw hole when fully tightened, I filed a substantial flat in the 6mm.
Then found a button head screw to fit in the grub screw hole and cut/filed it to suit.
Used loctite blue on this screw and - hey presto it will not come loose again.
Now... what's next? (...as we know with these machines that we love - there's always a next)
Cheers
 
I use the AN version on MK3 and their version for pre-MK3.

I tighten the set screw very tightly and with blue locktite, but every time I wonder why I don't just use locktite on the stationary end as I can't imagine why I would ever need or want to remove the stationary end. AFAIK, AN does not sell the individual parts for the pre-MK3 front so there's really no reason to ever unscrew it. They do sell the individual parts for the MK3 but don't say which are different from pre-MK3 and which can be used to replace parts in the pre-MK3 kit.
 
L.A.B. said:
I searched 'vernier'.
Click to expand...
I guess I should use search for more than part numbers! I generally go to the basic year I'm looking for and I checked them all before I posted - that's why I said AFAIK.

Simon can expect a "suggestion" email when he arrives Monday! He generally fixes/has fixed anything confusing that I tell him about.

Now I'm wondering what the difference is - I have both and have installed both and have never looked into which parts are different in the MK3 and pre-MK3.
 
L.A.B. said:
The pre-Mk3 mount tube is longer so the pre-Mk3 adjustable collar is thinner.
Click to expand...
According to AN, the only difference is the abutments and adjuster collars. The web site is being updated so it's easy to find them in the drawings and lists.

MK3:
06.5514 (Abutment)
06.4665 (Adjuster Collar)

Pre-MK3:
06.5514/1 (Abutment)
06.4665/1 (Adjuster Collar)
 
To close my side of this thread - I was dreading what I might find in the rear iso - much harder to fix!
Good news, there was a grub screw fitted and, even better, there are witness marks on the inner tube that show nothing had moved.
Cleaned it all and re-installed (very tight) with loctite 243 (blue)

Now, onwards and upwards!
Cheers
 
seattle##gs said:
With the motor resting on the iso, the gap at top is smaller than the gap at the bottom so I split the difference.
Click to expand...
A late response, but if you have a correctly adjusted Mk3 spring on the top iso then there is no vertical load on the front iso, so the gaps are the same. You can retro-fit the spring to earlier isos.
I've given up on measuring "gaps" and now using number of holes loosened from "snug" on the vernier adjuster. 3/4" 20 TPI and 8 adjustment holes gives 6 thou per hole. No squeezing the cradle over to get a feeler gauge in. The gap is what the gap is - thread pitch does not lie.

Just have to learn what the "good" number of holes (front and rear) is good for your bike at the moment. Currently for me 2.5 holes at the front and 2.0 holes at the rear is good. I check and adjust every 500 -1000 miles.

Also - why is the adjuster hole on the front 11/64" while the rear is 5/32"? I presume mine is some sort of "standard" (AN?). Best tool for the rear is a 5/32 drill bit, bent at the blunt end (about 30 degrees) with tape over the sharp flutes. Similar for front, though straight will do.
Cheers
 
Last edited:
Mine is 2.5 front and rear. Before I adjusted them a couple of months back they were 2.5 F 2.0 R and had some intrusive vibes ie they didn’t recede @ 3k. Now they’re gone and since the new rear tyre especially the bike handling is sharp so I’m happy as is.
 
Just caught up on this thread. I have hemmings vernier isos and like the idea of using brass grub screws. Does anyone remember the thread of the grub screw so I can buy some? Thanks in advance.
 
ilikevelos said:
Just caught up on this thread. I have hemmings vernier isos and like the idea of using brass grub screws. Does anyone remember the thread of the grub screw so I can buy some? Thanks in advance.
Click to expand...
The search button is your friend 😜

YING

Post in thread 'Hemmings Isolastic Adjuster'

Stephen Hill said:
Does anybody know where you can source the Hemmings style nylon tipped set screws?
Last time I bought them (years ago) it was from Mick.
Click to expand...
Stephen,
Go to McMaster-Carr.
M4-0.7X5 nylon tip stainless steel hex socket set screws
Comes in packets of 5
Mike
 
The nylon tip is only for protecting the thread right ??

If it were me I'd use a standard grub screw ( flat bottom with just a light " gripping " serration on it " and place a disc of annealed copper between the screw and the thread.

This will allow significant tightening to be achieved but without the thread being damaged - the copper deforms to take on the shape of the thread.

I used this method decades back when building high speed precision wrapping machines where large numbers of gears, cams, rockers and genevas etc would be attached to shafts and subsequently locked into position ( multiple adjustments usually ) whilst setting them all up for timing / position / function. ( all driven by big triplex chains usually )

When all was finally " timed and tested each component would be drilled and reamed for a taper pin to allow future dismantling when something somewhere would break - something would always break if the product was made too hard or soft.

Anyway when future dismantling was needed all was easy as the copper disc would prevent any galling on the shafts meaning they would simply slide / rotate off.

^^^ Don't see why It couldn't work for someone in this application

edit : I may have mentioned this on another occasion, apologies if any repetition.
 
Grandad said:
If it were me I'd use a standard grub screw ( flat bottom with just a light " gripping " serration on it " and place a disc of annealed copper between the screw and the thread. This will allow significant tightening to be achieved but without the thread being damaged - the copper deforms to take on the shape of the thread.
Click to expand...
This is basically what I did with my Hemmings adjusting set screw. Instead of a copper disc however, I used a 3/32 inch diameter annealed copper ball and a set screw that has a nylon locking patch that is on the threads. I then ground the end of the set screws flat.

When the set screw is tightened against the copper ball, the ball flattens out and conforms to the threads it is pushing against. As long as you use that same threaded hole, this flattened copper ball will last a long time. If you choose to use another threaded hole, just go ahead and use a fresh, new copper ball.

I've had very good success with this set up. As for the set screw (grub screw) size it is M4 x 0.7 and 5 mm long.


Peter Firkins
 

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