Is a Front Vernier Iso-lastic Upgrade Worth the Trouble?

I did the front iso vernier conversion on my '74 MKII without issue and no pivoting of the engine. If you go for it, be sure to order the correct type conversion kit as the MkII frame is slightly narrower than the MKIII at the iso mounting tabs.
I also did the Dave Taylor Headsteady with MKIII suspensory spring. The original rubber type headsteady bits do fail over time but most dislike them b/c they permit too much side to side movement of the engine, no awy to adjust it. This can give poor bike handling as it tends to "hinge" the isolated rear half of bike during hard cornering. THe Upgraded steadys help reduce/eliminate that.

You need to prepare your bank account for Norton impact....I've spent more than $10,000 on my bike in first 4 years owning it and it was basically operational when I got it (have not restored it).

My advice, hold off on the shopping sprees until you've got it running and have ridden it for a few months. You'll know then what actually needs attention and whether this bike is for you.
 
Tornado said:
If you go for it, be sure to order the correct type conversion kit as the MkII frame is slightly narrower than the MKIII at the iso mounting tabs.
Click to expand...

It's the Mk3 front Iso. mount tube that is shorter to accommodate the wider Mk3 threaded adjuster so a pre-Mk3 model needs the vernier conversion kit Iso. with the thinner threaded adjuster.
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk
 
Tornado said:
I did the front iso vernier conversion on my '74 MKII without issue and no pivoting of the engine. If you go for it, be sure to order the correct type conversion kit as the MkII frame is slightly narrower than the MKIII at the iso mounting tabs.
I also did the Dave Taylor Headsteady with MKIII suspensory spring. The original rubber type headsteady bits do fail over time but most dislike them b/c they permit too much side to side movement of the engine, no awy to adjust it. This can give poor bike handling as it tends to "hinge" the isolated rear half of bike during hard cornering. THe Upgraded steadys help reduce/eliminate that.

You need to prepare your bank account for Norton impact....I've spent more than $10,000 on my bike in first 4 years owning it and it was basically operational when I got it (have not restored it).

My advice, hold off on the shopping sprees until you've got it running and have ridden it for a few months. You'll know then what actually needs attention and whether this bike is for you.
Click to expand...
I bought the bike running. and put a few hundred miles on it before the layshaft bearing locked up. Fortunately in low gear just after turning a corner. I had planned on doing the upgrade over winter anyway.

Is a Front Vernier Iso-lastic Upgrade Worth the Trouble?


I want the bike ready for travel by spring. Getting an early start will give me time to get everything sorted.
 
If your front ISO is original it's not doing you any favors. If you like the shimming process at least replace the innards with new rubber. The RGM vernier conversion can be adjusted in minutes and will give you the opportunity to try different settings.

Don't be one of those Commando owners that fixes a broken part, but fails to see that part's relationship to other parts/systems. As a part begins to wear out (fail) it passes an increasing amount of the stress it bears to other parts which makes them wear faster, they, in turn, pass their stress down the line, yada, yada.

Best,
 
Dan1950 said:
I bought the bike running. and put a few hundred miles on it before the layshaft bearing locked up. Fortunately in low gear just after turning a corner. I had planned on doing the upgrade over winter anyway.

Is a Front Vernier Iso-lastic Upgrade Worth the Trouble?


I want the bike ready for travel by spring. Getting an early start will give me time to get everything sorted.
Click to expand...
I'm glad I did the R.P.P.S. (Replace the Portuguese Piece of S***), aka the layshaft bearing prior to a failure....but got a few thousand miles riding beforehand. I did the whole job without pulling the GB from the frame. I followed the Mick Hemmings DVD on gearbox teardown/rebuilding and used his recommended higher spec ball bearing, not the popular roller type. Mick's guidance was that roller type here can increase bending stress on the layshaft, and he'd seen failures due to this (he's done hundreds of rebuilds). The ball unit with phenolic cage allows some flexing as per original design.
 
RoadScholar said:
If your front ISO is original it's not doing you any favors. If you like the shimming process at least replace the innards with new rubber. The RGM vernier conversion can be adjusted in minutes and will give you the opportunity to try different settings.

Don't be one of those Commando owners that fixes a broken part, but fails to see that part's relationship to other parts/systems. As a part begins to wear out (fail) it passes an increasing amount of the stress it bears to other parts which makes them wear faster, they, in turn, pass their stress down the line, yada, yada.

Best,
Click to expand...
Well the bike came with 24 years of service history and was very well maintained. Other than the layshaft bearing and brake drum circlip issues, both of which are common hidden pitfalls as I understand, the bike is in pretty good nick. I just want to add some upgraded tp the numerous ones already present.
 
Dan1950 said:
Well the bike came with 24 years of service history and was very well maintained. Other than the layshaft bearing and brake drum circlip issues, both of which are common hidden pitfalls as I understand, the bike is in pretty good nick. I just want to add some upgraded tp the numerous ones already present.
Click to expand...
The "problem" with a few smallish upgrades at a time is, THAT list is never ending! One year you do two or three, then next year one or two, the next year three or four, and after about 10 years the first stuff you put on needs to be replaced again!
 
My Commando was restored with low miles post resto. Currently, I'm about 8 months in and $2500 further on in parts. Things that had to be done, but weren't predictable, as I worked through the bugs in the system. Just like you found with the GB, unfortunately. I doubt I'm finished.

However, it did not affect me riding the bike. Parts availability and delivery has been good. The support on here has been phenomenal.

I have a thing that I don't like to finish for the day with the bike not ready to roll. I missed that target on a couple of occasions, where I spotted some other issue that meant downing tools to wait for a part. But, on the whole, it was ready to ride when I wanted. So, just saying, Spring is a good target. But, if it's an important factor, keep some budget back, just in case. Despite that, my experience, fixes are generally quite quick, if the bike is basically sound. You should expect to be able to ride when you fancy.

My impatient upgrade was an Interstate tank / seat. I should have waited, in hindsight. I'm now over what I budgeted :cool:. Love my tank and seat though!
 
grandpaul said:
The "problem" with a few smallish upgrades at a time is, THAT list is never ending! One year you do two or three, then next year one or two, the next year three or four, and after about 10 years the first stuff you put on needs to be replaced again!
Click to expand...
I'm a bit OCD and I find that I do better if I go all out. That allows me to concentrate whereas when I do things piecemeal I spend a lot of wasted time getting restarted. I've done frame up (custom) builds which require assembly, check, teardown, reassembly, repeat and so on. I always did well getting through to completion albeit sometimes running late into the riding season. Usually I get a late start but this time I have the time and budget to get it done. As soon as I make some disassembly tools for the gearbox I'll be able to finalize my list. I want to start work in earnest after the 1st of the year. I have several small projects to work on in the mean time. Once the gearbox, is complete I will tackle the upgraded head-steady and front Vernier Isoelastic. After that I can concentrate on smaller projects and complete then one at a time.

One thing I'm not planning on doing is changing the appearance of the bike other than some cleaning and polishing of the aluminum. The bike is a well preserved survivor with all the little nicks and dings that give it character.
 
L.A.B. said:
It's the Mk3 front Iso. mount tube that is shorter to accommodate the wider Mk3 threaded adjuster so a pre-Mk3 model needs the vernier conversion kit Iso. with the thinner threaded adjuster.
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk
Click to expand...
Les
I've been wandering along for a while just using the "back off by 1 1/2 holes" to give the, apparently, correct 0.006" gap.
I believe you're a fan of using a feeler gauge.
So... I had a go today and could not fit a 6 thou gauge in, no matter how I tried (front iso).
So I backed the front bolt off, snugged the iso up then backed it off 3 holes. I could then get a 15 thou gauge into it - levering the engine over with a piece of soft timber. Then tightened the bolt and rechecked. Even with levering over (I must be doing it wrong) I couldn't even get an 8 thou gauge into it.
Then checked the MK3 manual (to see what I might be doing wrong) and it says...
Screen Shot 2022-04-15 at 8.19.20 pm.png
Can you offer any advice on what I may be doing wrong?
Otherwise I'll just go back to the 1 1/2 hole method.
Cheers
Rob
 
robs ss said:
I've been wandering along for a while just using the "back off by 1 1/2 holes" to give the, apparently, correct 0.006" gap.
I believe you're a fan of using a feeler gauge.

So... I had a go today and could not fit a 6 thou gauge in, no matter how I tried (front iso).
Click to expand...



Yes, because of the play in the Iso adjuster threads, the gap is likely to close up when the through-bolt is tightened, the "back off by 1 1/2 holes" method, to me, isn't reliable so the gap should be checked with a feeler after the bolt has been fully tightened.

robs ss said:
So I backed the front bolt off, snugged the iso up then backed it off 3 holes. I could then get a 15 thou gauge into it - levering the engine over with a piece of soft timber. Then tightened the bolt and rechecked. Even with levering over (I must be doing it wrong) I couldn't even get an 8 thou gauge into it.
Click to expand...

Yes, you should only lever to check the gap with the bolt tight. If you lever with the bolt loose you may get a false 'wide' measurement.

850 Mk3 manual, F13, 4. The bolt is slackened after checking the gap if adjustment is required.
Is a Front Vernier Iso-lastic Upgrade Worth the Trouble?
 
L.A.B. said:
Yes, because of the play in the Iso adjuster threads, the gap is likely to close up when the through-bolt is tightened, the "back off by 1 1/2 holes" method, to me, isn't reliable so the gap should be checked with a feeler after the bolt has been fully tightened.



Yes, you should only lever to check the gap with the bolt tight. If you lever with the bolt loose you may get a false 'wide' measurement.

850 Mk3 manual, F13, 4. The bolt is slackened after checking the gap if adjustment is required.
Is a Front Vernier Iso-lastic Upgrade Worth the Trouble?
Click to expand...
So, how many holes do you find is necessary to back-off in order to get 6 thou with the bolt tightened (30 ft/lb)?
 
robs ss said:
So, how many holes do you find is necessary to back-off in order to get 6 thou with the bolt tightened (30 ft/lb)?
Click to expand...

As I don't actually use the 'holes' method then I couldn't say.

You could set it to 6 thou with the bolt fully tightened then slacken the bolt and count how many holes it takes to go back to zero play?
 
robs ss said:
Les
I've been wandering along for a while just using the "back off by 1 1/2 holes" to give the, apparently, correct 0.006" gap.
I believe you're a fan of using a feeler gauge.
So... I had a go today and could not fit a 6 thou gauge in, no matter how I tried (front iso).
So I backed the front bolt off, snugged the iso up then backed it off 3 holes. I could then get a 15 thou gauge into it - levering the engine over with a piece of soft timber. Then tightened the bolt and rechecked. Even with levering over (I must be doing it wrong) I couldn't even get an 8 thou gauge into it.
Then checked the MK3 manual (to see what I might be doing wrong) and it says...
View attachment 94366
Can you offer any advice on what I may be doing wrong?
Otherwise I'll just go back to the 1 1/2 hole method.
Cheers
Rob
Click to expand...
The backlash in the adjustment threads gets pushed to one side when the through bolt is tightened. The backing off amount must accommodate this. I just checked gap after nipping up the through bolt, loosen & adjust as needed. 2 or three tries got me right there.
 
Craig said:
Yup , why not …. I thought everyone just went ahead up upgraded the ISO’s , along with a modern head steady ….. surely I wasn’t alone doing it that way …
Click to expand...
Well call me old school, but I’m not one who has converted. Box section top mount from an 850 added as my ’72 head steady did crack.
 
L.A.B. said:
As I don't actually use the 'holes' method then I couldn't say.

You could set it to 6 thou with the bolt fully tightened then slacken the bolt and count how many holes it takes to go back to zero play?
Click to expand...
I just did that on the front - after a fair bit of mucking around (that RH bolt head on the front isn't easy to get to) found (on mine) that actually 2.5 holes from "snug" gives 6 thou, when torqued up - which would suggest that I've been running on a bit under 4 thou (1.5 holes).

There must be different versions of the Mk3 manual because my clip (#33 above) is from a manual, as is (I presume) yours in #34 above. Quite different instructions!

Anyway - next is a ride test and then maybe further adjustment (of the rear).
Cheers
 
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