Are Isolatic Upgrades any Good

Hello all, I have a 1969 Commando I am just about to start rebuilding.

I have read a lot on this site about Isolastic upgrades, various makes of upgrades (Vernier or shim), later variations from the factory etc. etc.

Where as I appreciate the setup and maintenance advantages of the upgrades, but .... do any upgrades give significent advantage in operation over the standard 1969 factory setup.

I plan to restore the engine in standard tune.

Thanks ..... Richard

The older non-venier ones are difficult to adjust.

The main advantage of the later style is adjustment. They all function the same when set up properly.

tribonnie said:

Hello all, I have a 1969 Commando I am just about to start rebuilding.

I have read a lot on this site about Isolastic upgrades, various makes of upgrades (Vernier or shim), later variations from the factory etc. etc.

Where as I appreciate the setup and maintenance advantages of the upgrades, but .... do any upgrades give significent advantage in operation over the standard 1969 factory setup.

I plan to restore the engine in standard tune.

Thanks ..... Richard

Click to expand...

The isolastic headsteady is an improvement over the standard rubber bushes and side plates.

The performance of the vernier isolastics and the stock shim set up is about the same ( the aftermarket rubber may not be exactly the same spec...). Adjusting the rear isolastic is a bit of a pain because it is hard to get at it. The front is right there and easy to reshim. I just went with the adjustable rear on my bike.

Greg

+1 on the isolastic headsteady but suggest you can take it to another level by taking a look at what Herb Becker has done on several of his Commando race bikes. Besides changing the combination of rubber doughnuts in the iso units he supplements with two pairs of teflon rubbing blocks, one at the head steady (no doughnuts necessary there) and one beneath the trans. This set up gets a bit complicated as these are one off items and unless you have the ways and means of a machine shop it is probably best to stick with off the shelf enhancements. Do a search for Doug McRae on this forum and you should be able to find a good narrative with pictures of the Herb Becker modifications.

Colorado Norton and a few others have nice off the shelf head steadies, iso style and heim joint styles.

The vernier retrofit kit I bought was made of Stainless, and plates had a concave face to them (a machining pitfall), AND a horrid record groove surface finish which I thought would be detrimental to longevity of the Teflon washers.


I contacted the seller, asked if they were all like that, or did I get a poor example. He was rather put out, and his answer was "over and out". Very impressive. So I set to work RE-working them to make them usable... here you can see the outer edges coming into a polished state.




It took a lot of work to get A) the face FLAT, and B) a reasonable surface finish that would not eat up the Teflon washers. I didn't take a picture of the finished parts, in too much of a hurry.
Normally, I avoid Stainless like the plague, but this is a GOOD application for it.. carbon steel will rust when rain/wash water collects inside the boot. Iron oxide gobbles up bushes, whether bronze, plastic or Teflon.

If avoiding the helm joint link path, check out Ludwig's 300 lb Commando thread for a view of about best example of rubber type steady that not complex per say as its so minimalist in contruction. My upgrad on two pleasing Combats is to bevel 45" angles on the big front cushions leaving about 1/3" inch contact rim, yum. The looser the gap is set the more sloppy the handling but the tighter set the higher the isolation rpm, so adjustable can dial in to your taste and keep it that was as wear occurs. Also not bad idea to stuff two more big cushions in rear.

Good work polishing flat your shuffler-washer surfaces. I now believe that the jointed headsteady makes a huge difference in P.T.F.E. or even super slippery Teflon washer life as all those sideways forces are nixed. Try leaving the rear iso dustcovers off entirely. Yah.

In the bit of information I gleaned during my rebuild, there are 750 isolastic rubbers and 850 ones which are stiffer. So if you buy new ones, use the 750 nomenclature. Since you're in the UK it will be easy to call Mick Hemmings and for not much money, you can buy the Hemings vernier isolastic kit, it's about the easiest way to get rid of the shims and no machining of parts necessary, plus you use all your old parts. The Norvil one requires all new parts. Head steady are lots of options, the 69 version is prone to breakage. The 850 boxed style is adequate. I'd suggest a DIY heim joint type or if you can fabricate or get someone to do it, the ludwig one is about as easy as it gets. Lots of people seem happy with the Dave Taylor one, but I don't care for the way it clamps to the frame. If you can afford it the CNW one is real nice.

Also if your bike is early enough, you will need new tubes for the donuts, plus the circlips which were absent on the 68/69 version. There's even an earlier one with outer tubes, just get rid of that arrangement if you have it and go with the 71 arrangement. http://www.oldbritts.com/1971_g9.html

Dave
69S

I found the pic after fully polished

One of the reasons I converted my Norton to a Featherbed frame, balanced crank and steel mounts no more problems and a better handling bike to boot

Ashley

Thanks everyone, I think I will initially stick with the standard setup. I am new to Nortons (might guess from my user id) so maybe re-shimming etc is the best way to learn this isolastic stuff.

thanks again .... Richard

tribonnie said:

Thanks everyone, I think I will initially stick with the standard setup. I am new to Nortons (might guess from my user id) so maybe re-shimming etc is the best way to learn this isolastic stuff.

thanks again .... Richard

Click to expand...

I agree with the learning curve and re-shimming as needed but whether you go full blown vernier or standard, there is nothing like good fresh rubber in there to work with and to get a good feel and feedback with the shimming that you do.

Hi Richard,
Vernier isolastic adjusters are worth putting on if your taking bike to bits. they are easy & quick to adjust when tunning clearances to suit your riding preferences. The modern head steadies are much better than the standard original setup if you want tighter handling. You have a choice of Norvil head steady from Mick Hemmings, Fair spares, Andover Norton etc or the Dave Taylor type that I use from RGM Motors in Cumbria. There are also some other types but these are the main 2 available in the UK.
Also tyres make a big difference to handling. I have found Avon Roadriders make the bike handle much better than the original Dunlop TT100 that I used for years.
Also I have to say again today that joining the Norton Owners Club is well worth it as there are lots of interesting bits of info regarding improving your commando on their website & some info is only available to members.
However THIS site is brilliant for getting good info if you need it, with a wealth of knowledgeable people to help you.
Good luck & maybe see you at some Norton Rallys.

Don,

I have a pair of 19" original Borrani WM 2-rims on my 750, useful advice on tyre widths with roadriders, the bike is currently fitted with a pair of 4.10 Roadrunners and the tyres look pinched. I have not got the bike running yet and as the tyres are at least 10 years old, they will be replaced shortly.

Verniers are very handy for the rear - not quite what I'd call a MUST - DO, but pretty close. The fronts are fine as oem IMO since they are quite easy to deal with though certainly verniers are even easier. The fronts require adjustment more often than the rears but I put in all new iso rubbers/shims more than two years ago and have not had to re-adjust the fronts (or rears) yet so it's not like it's a frequent requirement. I set mine at .006 and have been very pleased with the handing/vibration.

FWIW, on my bike, A set of swing arm clamps and new swing arm bushings made a much greater improvement in handling than the new ISO rubbers/any clearance changes. IMO swing arm clamps ARE a "must-do!"

Yep adjustable sure nice labor saver to narrow down gap in stages to get best compromise of vibe threshold vs handling threshold and long term maintenance of this nice state. Swing arm collars are good mainly to prevent spindle bush deforming wear and slop and then secondarily helps somewhat better handling before isolastic-frame Hinge onsets > if fun fool enough to press long held lean loads to actually run into handling limits that makes *untamed* racing C'do's very very rare but for stock cycle classes. Isolastic shimming is a pain so tends to get neglated over the long haul. Pay back takes some years or decades to notice of course.

Replaced the front & rear isolastics with the adjustable Verniers and installed a MK3 Headsteady for my 72. Major improvement. Much better ride and less vibration overall. Glad I installed these upgrades. Was worth the money & time.

Vernier's are GOOD

Is it just me or are vernier iso rather hard to adjust to point of both bending the probe and wallowing out the holes? I've two sets that are buggers to adjust, one common off the shelf steel version in factory cradle mount, the other anodized 7071 TS in custom alloy cradle, first one crashed on but not the second one. The supplied probe would bend about the time the adjuster moved so modified a hex wrench that didn't fit quite as well so the holes tends to wallow on torque required. There is some bedding in & rubber softening/sagging interval before reaching a stable state of good low isolation. Also note tire pressure as that's mainly what the iso work against so harder tires give better engine isolation but transmit more road texture shocks. Air borne is worst as almost full vibes hit instant tires leave surface and once I instantly diagnosed a rear blow out 50 mph as I left hwy to enter paved 2ndary rd, .5 sec of engine vibes then about normal straight ahead but glanced to be sure and slowed down d/t turns to deal with rest the way home, w/o much engine vibes. Strange critters these isolastic animals. I have used lots of different old and new tires with a handful of slow leak events that are first noticed in vibe sense then slight wind gust sense then fight it to side of road sense, to have a firm opinion now that your really can't tell much, diagnose or evaluate isolastics and handling w/o both tires in great shape and air balanced, nil clutch wobble and chains adjusted well and decent shape and head steady in neutral as possible alignment. Even dang muffler mounts and header clamps can feed back at some frequencies. I am addicted to the smooth onset and going around turns briskly and tell ya I'm really pleased with beveled front cushions and two or more extra's in the rear in two Combats so far. One pretty crooked yet so more dicy to get adjusted and thought I'd have to diddle the front at frist but just got better and better over couple 1000 miles ao I'm glad I didn't diddle it too soon and deal with the above adjusting question again. I carried wrenches to loosen iso's and diddle front and rear up and down every few miles for dozens of miles to get a sense of what I liked - mostly close to factory gap.