Production Racer Head Steady Setup?

hudson29 said:

bwolfie said:

After removing the powdrecoat form the mating surface and tightening the center bolt fully, I had .015 clearance. So scrape off the powder coat and take a measurment. THen shim with factory rear iso shims as required.

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For those of us who are just a little thicker than average, can you be more specific as to where to remove the powdercoat from and where to add shims? Also, where do you take the measurement? What constitutes fully tightened? The manual was somewhat breezy on these topics.

Vintage Paul

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I drew arrows!

Flo said:

Right, the cups fit over the ends of the tube on the main bit. The shims go inside the cups to shim out towards the soft washer.
So remove all paint from the end faces of the tube. Place cups onto tube & make sure the inside of the cups nare up against the tube.
Place yer soft washers onto spigots on end bits, threads bolt through 1 end bit, then through middle hole on headsteady, then place on other end bit & do nut up.
When done up, you should be able to rotate the cups. Then get a feeler & shove in between soft washer & cup. Thats how much clearance you have.
For example, if you have .023" clearance, then you would need to put .013" of shims inside the cup to shim it out from the tube, to get .010" recommended clearance. In my case I would put .020" 'cause I would be happier with .003" clearance.
Got writers cramp now!
P.S. As Mr. bwolfie just said while I was writing this.

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+1 on the clearance. I prefer that iso as "snug" as possible. FWIW, I was fortunate that when I purchased my bike, it had the third iso on it already, holding that part in one had and having a known original PR head steady in the other, there is zero difference nit-picking every part of it. When the Dave Taylor unit was available, I switched out to that piece and ran it for a few years. I have since switched back to the iso...and sold the Taylor part. I wouldn't hesitate to recommend a rose joint set up, but for me, I like the feel of the iso...and the period correctness.

Am I missing something here? I mean the CNW head steady looks to be the best engineered answer out there to me, am I wrong??? I know I gotta save up for it, but the bikes paid off, so I look at buying the parts as sort of a trade off to a monthly note, anyway ...allowing up and down movement while keeping side to side play at Nil is the whole idea right .....or does the CNW transfer too much engine vibration? Cj

cjandme said:

Am I missing something here? I mean the CNW head steady looks to be the best engineered answer out there to me, am I wrong??? I know I gotta save up for it, but the bikes paid off, so I look at buying the parts as sort of a trade off to a monthly note, anyway ...allowing up and down movement while keeping side to side play at Nil is the whole idea right .....or does the CNW transfer too much engine vibration? Cj

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No, you are correct, the Comstock design headsteady is probably the benchmark for headsteadies. But people like choices and variety.

Paul
If after removing the powdercoat from the end of the tube you still have a clearance problem the fix is easy. Slide a thin 1/2" washer onto the bolt against the iso rubber steel liner and then bolt the unit up. ie the washer is fitted inside the steady. You should then have excess clearance and will have to shim the end caps.
Ando

ando said:

Paul
If after removing the powdercoat from the end of the tube you still have a clearance problem the fix is easy. Slide a thin 1/2" washer onto the bolt against the iso rubber steel liner and then bolt the unit up. ie the washer is fitted inside the steady. You should then have excess clearance and will have to shim the end caps.
Ando

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You need to add similar shim/washers behind the side plates for the bolts that thread into the frame and where the plate attaches to the clamp or the side plates will be canted. Or, in the case of the original Norvil product, bent. Then, when you mount it up to the frame you'll find that the quality control of frame construction didn't extend to making sure that the threaded bosses that the plate bolts to were dead nuts equal length from the centerline. If you don't keep the plate square to the iso unit it will not have equal gap all the way around.

BTW, the picture you posted has the clamp in the back, it's reversed. There was a reason the original Norvil unit had slotted holes for the head bolts.

I think this may be the answer to why they dropped the iso headsteady from the the bike when it went into production. It wasn't financial, it was because they are nearly impossible to set up. It may also explain why they used those ridiculously soft PTFE washers too.


http://www.norvilmotorcycle.co.uk/techtalk06.htm

Sorry, the head steady of the production racers was never meant to go on production bikes. The drawing we have was done by Peter Williams in 1969, i.e. definitely not in the planning phase for Commandos. Peter drew what was needed in the race team, nothing for production motorcycles- that wasn't his job.
I have ridden most of my Commandos over the years with the Production Racer (vulgo "Norvil") type headsteadies, and run my current signal orange shortstroke Roadster with one of ours (Andover Norton's), redesigned by my son Tim. No problems whatsoever with setting it up, and maintenence is minimal. Then again, our bodies are zink plated, not plastic coated, and we have learned a lesson or two from other people's attempts. Ours have two elements in them, not just one, and are more stable probably than the one element variety.\

The bike runs like it was on rails, most noticeable in 80-90mph bends and VERY different to standard headsteadied Commandos. Confidence-inspiring to the point where one is tempted to willfully upset the handling!

Joe

JOe
What do you mean by one element and two element? I have a Norvil HS on my bike; do you class that as on or two element?
thanks

The original design by Peter Williams relied on two rear isolastic "bushes" (the elements with the metal tubes bonded in) in shortened form pressed into the main body of the head steady. This we copied for our head steadies. A lot of headsteadies I saw went the easier & cheaper route of putting just one "bush" in. The two-bush variety stabilizes the whole assembly more than the one-bush version, but makes it more difficult to slim everything down enough to fit the headsteady under standard production petrol tanks. These have a narrower "tunnel" for the top frame tube than the original production racer tanks.
What you have I do not know. The name "Norvil" these days covers a multitude of sins. Is it a genuine one, a Fair Spares "Norvil" one, a Norman White one, or a Mick Hemmings "Norvil" one? Only with the genuine article of a genuine 1970s production racer I know for sure it has two elements. The others I simply don't know/can't remember.
Joe

I believe the Hemmings Norvil variety is actually made by Norman White.
It uses a single central rubber bushing (at least the Norman White version does).

rpatton said:

ando said:

Paul
If after removing the powdercoat from the end of the tube you still have a clearance problem the fix is easy. Slide a thin 1/2" washer onto the bolt against the iso rubber steel liner and then bolt the unit up. ie the washer is fitted inside the steady. You should then have excess clearance and will have to shim the end caps.
Ando

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You need to add similar shim/washers behind the side plates for the bolts that thread into the frame and where the plate attaches to the clamp or the side plates will be canted. Or, in the case of the original Norvil product, bent. Then, when you mount it up to the frame you'll find that the quality control of frame construction didn't extend to making sure that the threaded bosses that the plate bolts to were dead nuts equal length from the centerline. If you don't keep the plate square to the iso unit it will not have equal gap all the way around.

BTW, the picture you posted has the clamp in the back, it's reversed. There was a reason the original Norvil unit had slotted holes for the head bolts.

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Thanks for this, I'll keep an eye on the plates being square. The triangular plates have a long side & a short side. Which goes forward?

Vintage Paul

swooshdave said:

hudson29 said:

If I were to guess the powdercoating may be too thick here. There shouldn't be any at all here. He mentions there may be production QA issues here too. If he can post the production spec for that part you'll know how far off it is.

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Thanks for this picture, it made it quite clear where the powder needed to be removed. Dan, one of my cronies came over last night and with the handy dandy Dremel removed the powder just in that area. We made a couple of very thin shims but ended up with no shims at all, the clearance probably being .008. It is had to say for sure as the black plastic biscuit is somewhat grippy and that made it hard to judge the resistance. I think we will try this just this way and see how it goes.

From running the motor & riding the bike, how will I be able to tell if the setting is too tight or too loose?

Vintage Paul

I'm chiming in a little late here, but I have some positive experience with the original PR top iso. I raced my PR for quite a few years with the original PR isos, including the top one. I started racing it in stock forrm with the original K81 tires and 750 engine, and eventually ended up with a 920 engine and period 18" slicks. It was always very stable at speed, and particularly good in high speed sweepers. I never had any handling issues with it, except when parts broke (rear axle, swingarm, front fork slider). It didn't turn in as quickly as modern bikes, but neither did most of the other race bikes of the period. The only maintenance I ever did on the isos was to regularly check and adjust the clearance. I ran them well under .010" clearance, but still loose enough that I could turn the plastic washers. I did experiment with running them really tight, but all I got was more vibration, with no change in the handlilng. The newer linkage setups that seem so popular here might be even better, or might not. I haven't tried them, so can't say. I can say that properly set up triple isos work quite well, certainly good enough to run with the AMA Pro Twins bikes back in the day.

Having said that, I think I'll still try the linkages on my street bike next rebuild, just out of curiosity.

Ken

Paul,
You might want to put a little silicone or rubber lube on the black rubber bush so that it is able to center itself. Over time they all seem to glue themselves to the inside of the tube but at least it makes setup easier.

On the Norvil plates the short side of the triangle goes in the front. Everybody has a different way to go about setting up iso's. I like to start off on the tight side and increase the gap till I see the vibes lighten up till it's acceptable. If you get to a 10thou gap and the vibes haven't calmed down then the headsteady might be binding somewhere.

Joe,
I've never seen one of the original Widowmaker frames so I don't know how they set up the early headsteady without the small cross tube. But I'd guess they would have had a pretty hard time putting an iso up there even if they wanted to. Another myth busted regarding dropping the iso heaadsteady for financial reasons.

Norvil has headsteadies in zinc coated and stainless. They have two shortened iso bushes in them. The side plates on mine were much too thin and needed replacing with thicker stainless. The overall build quality wasn't great.

Bob,
You are right, of course, that the Proddy Racer headsteady quite simply can not be installed with the early Commando frames. If you want to see a "widowmaker" frame my '68 Fastback still has it and it is not broken (yet). I did not let Bob Rowley ride it though, works tester in that era, who told me how to break it within a VERY short distance.
As I said, the original head steady drawing dates to 1969, the Commando was developed in 1967, the brace tube on which the head steady is fixed only came in after several months of production (but was there in 1969), enough said.
One of the reasons for doing an Andover Norton headsteady- which was never going to be a mass seller, though it sells surprisingly well- was the dire quality of the ones I had bought elsewhere. I just did not see myself willingly pay money for the quality I had learned to expect, so unscrupulously exploited the fact my son wanted one for his Commando and talked him into CAD redesigning one and organizing its production. Now we both have one on our everyday Commandos.
Joe

After messing around with the new head steady, we think we have a way to assure alignment. We used a couple of the steel iso shims to lock up the assembly while it is being assembled. After the bottom section is bolted solidly down, we can take the side plates back off and remove the steel shims and re assemble allowing the iso motion to work again. Here are a few pics of the steady mocked up on the motor.

Here is the old Mk III version we are surplusing


The head ready for the new head steady


Here is the new head steady trial assembled to check the fit




We'll need to shorten an allen wrench to tightened the top saddle mount to the frame but everything else looks pretty tidy. The bike may run in the next week or two and we shall see how it goes with the new head steady. It has been twelve years since I last rode it so I'm not really sure how to measure any improvement it might make or tell if it needs any more adjusting. We'll just push ahead and see what happens.

Vintage Paul

You need a ball-end allen wrench to get those tight, better than shortening one.

ZFD said:

The original design by Peter Williams relied on two rear isolastic "bushes" (the elements with the metal tubes bonded in) in shortened form pressed into the main body of the head steady. This we copied for our head steadies. A lot of headsteadies I saw went the easier & cheaper route of putting just one "bush" in. The two-bush variety stabilizes the whole assembly more than the one-bush version, but makes it more difficult to slim everything down enough to fit the headsteady under standard production petrol tanks. These have a narrower "tunnel" for the top frame tube than the original production racer tanks.
What you have I do not know. The name "Norvil" these days covers a multitude of sins. Is it a genuine one, a Fair Spares "Norvil" one, a Norman White one, or a Mick Hemmings "Norvil" one? Only with the genuine article of a genuine 1970s production racer I know for sure it has two elements. The others I simply don't know/can't remember.
Joe

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this is my home made norvil style headsteady
it has only one iso in it and i do not think it matters much how many rubbers are in it
the aim is to reduce LATERAL play , only allowing up and down and forward and rearward movements
The way i set mine up is to drill out the two threads into wich the rubbers screw into the frame
, then mount the whole headsteady on the engine-head , setting it so that you can just rotate the cups wich go over the tube . Then measure the gap between the hole (where the threads were ) and the sideplates and turn up spacers to fill the gap .then put a bolt through the sideplates , spacers and frame and tighten everything up DONE

lynxnsu said:

this is my home made norvil style headsteady
it has only one iso in it and i do not think it matters much how many rubbers are in it
the aim is to reduce LATERAL play , only allowing up and down and forward and rearward movements
The way i set mine up is to drill out the two threads into wich the rubbers screw into the frame
, then mount the whole headsteady on the engine-head , setting it so that you can just rotate the cups wich go over the tube . Then measure the gap between the hole (where the threads were ) and the sideplates and turn up spacers to fill the gap .then put a bolt through the sideplates , spacers and frame and tighten everything up DONE

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I would propose that the two rubbers allow the rubber to expand easier, possibly reducing the vertical vibrations.

Has anyone switched from the DT rose/heim joint version to the Norvil/Hemmings/White version or vice versa, and noticed a difference?