Fitting a Norvil headsteady

Having read some of the negative comments about Norvil headsteadies on this forum, I am a bit hesitant about posting this, but...
I have a Norvil headsteady that I am fitting, and can't quite figure out the process for shimming it, and am now wondering if I have got it assembled correctly. The instructions say to shim "as detailed in the workshop manual". Someone has replaced the other isolastics on my 1970 Roadster with Mk 111, so I haven't experienced shimming before. The headsteady is to be shimmed to 0.01 inches. Questions: should there be shims fitted to both sides of the headsteady or just one side? Where do I measure the 0.01 inches? Have I got the parts in the right order? I've attached some photos:



This shows the whole unit in place on the bike.

I have put the plastic washers directly behind the plates:



is that correct - or should they go inside of the steel cover?:



Where do you measure the 0.01 inches? Should shims be fitted to both sides or just one? The shims fit into the steel cap, and if I have them in the correct place abut the rubber, but only the outside part, so that they restrict movement of the outside, but allow the inner part of the rubber to move:



I don't see why the shims make a difference; won't the steel outer plate just push into the plastic washer wheb it is tightened up witht hebolts on the outside?

Questions: should there be shims fitted to both sides of the headsteady or just one side? Where do I measure the 0.01 inches? Have I got the parts in the right order?

It doesn't really matter if you put all the shims on one side. You slip a feeler gauge between the PTFE washer and the endcap.

I don't see why the shims make a difference; won't the steel outer plate just push into the plastic washer when it is tightened up with the bolts on the outside?

The way the mount is designed is that tubing that holds the rubber doughnuts and indexes the sideplates is made intentionally long. That way you can adjust by fitting shims behind the endcaps to bring them up to the right clearance for the PTFE washers. It's easier to do this off the bike. You do the same thing with your vernier MkIII's, bring things into tolerances.

A few tips: Assemble the whole mount off the bike with the clearance set. If it doesn't fit when you mount it you need to make adjustments to the mounts. Do everything with the bike off the centerstand and level. Ditch the sideplates that it came with. They aren't stiff enough. Nice smooth and flat stainless in 3/16" works. Use wide hardened washers on the allen screws on the motor. Plan on spending a lot of time getting it right. Do you have a lathe? The spacers that came with the kit on mine were too long, the mounting block was too narrow. In other words, it's a reasonably designed unit. The execution was awful. If you like to fettle, this is the one for you. If not, consider a Dave Taylor headsteady.

Bob,

thanks for your help on this one. I think I understand the concept of it now. So far as I can tell (I have mounted it and had one test ride, before taking the tank off again) the side spacers are the correct length, and I didn't have a problem with the mounting plate - but I will get some better washers for it - wide hardened ones as you say. It is disappointing to hear that the side plates aren't stiff enough, but I did wonder about that. I will have to talk to my friendly engineering friend.

Question: I assume that the ptfe washers fulfil a role of being a secondary damper of vibration. Presumably they will degrade over time? A gap of 0.01 inches is a pretty fine tolerance; which I would have thought will change fairly quickly as a consequence of vibration squashing and narrowing the pfte washer. Presumably that measurement has been set with that in mind?

Chris T said:

Bob,

thanks for your help on this one. I think I understand the concept of it now. So far as I can tell (I have mounted it and had one test ride, before taking the tank off again) the side spacers are the correct length, and I didn't have a problem with the mounting plate - but I will get some better washers for it - wide hardened ones as you say. It is disappointing to hear that the side plates aren't stiff enough, but I did wonder about that. I will have to talk to my friendly engineering friend.

Question: I assume that the ptfe washers fulfil a role of being a secondary damper of vibration. Presumably they will degrade over time? A gap of 0.01 inches is a pretty fine tolerance; which I would have thought will change fairly quickly as a consequence of vibration squashing and narrowing the pfte washer. Presumably that measurement has been set with that in mind?

Click to expand...

Believe it or not but after about 10 years of use it was the side plates that had worn just shimmed mine today but have similar issues about the mounting block being too narrow and the spacers too short. When looking at the design it has a problem in that when the shims are fitted there will be clearance between the side plates and the spacers so when it is tightened up the plates will bend... :!: Making the side plates stiffer confuses me as they would have to be made to a very close tolerance for the whole head steady to fit correctly..or maybe I have confused myself for the last 10 years

Hi Chris
0.010” seems to be right for the gap, but you have to tailor this to how much vibration you get between what you had, and the new Head Steady. This Head Steady will improve your handling with a slight increase in vibration. One thing you must look out for is how close the bolts running at the bottom tube fixing points (Under the Main Spine Tube) and your tank tunnel. I know from experience that the heads of these bolts buzzed a hole in my steel Roadster tank and caused a small leak. Not good over a hot engine. If you have an Interstate/Fastback steel or fiberglass I am not sure of. Maybe some one else who has a Norvil Head Steady in this set up can pipe up with their 2 cents. Long story short…after the leak repair I had to Peen in the steel inner well close to these offending bolts to give it some more clearance.
Hope that helps,
Regards,
CNN

Hi Chris

Just looked at your photos again is the first in the group showing the head steady fitted and tightened up if so is there a gap between the side plates and the front mounting......?

Chris T said:

Bob,



Question: I assume that the ptfe washers fulfil a role of being a secondary damper of vibration. Presumably they will degrade over time? A gap of 0.01 inches is a pretty fine tolerance; which I would have thought will change fairly quickly as a consequence of vibration squashing and narrowing the pfte washer. Presumably that measurement has been set with that in mind?

Click to expand...

The PTFE washers stand up surprisingly well on the headsteady and the rest of the Iso's. They are actually a friction item rather than a vibration buffer.

plj850 said:

Believe it or not but after about 10 years of use it was the side plates that had worn just shimmed mine today but have similar issues about the mounting block being too narrow and the spacers too short. When looking at the design it has a problem in that when the shims are fitted there will be clearance between the side plates and the spacers so when it is tightened up the plates will bend... :!: Making the side plates stiffer confuses me as they would have to be made to a very close tolerance for the whole head steady to fit correctly..or maybe I have confused myself for the last 10 years

Click to expand...

You're right, that's exactly what will happen, it will bend, or be deflected out of square. You can get packs of various thickness sheets of stainless shim material to shim up the mounts under the plate where you need it. I think this is where the added vibration with this mod has come from.

I had plates made out of 3/16" stainless. Lapped flat, polished. Turned down the mounting bolts on a lathe to keep them away from the tank, ect... If you enjoy fettling, it's fun to get it right. In my view, this headsteady is to Amal's what Dave Taylor's headsteady is to Mikuni's. The Mikuni is a quantum leap up in design and execution. You'd have to be some kind of Luddite to ignore the advantages. Unlike Amals, (which have become a statement of fidelity to tradition), these don't even show. I have some issues with the design of Dave's unit. But in practice they work. To do it all over again, I'd get a Taylor headsteady and write the Norvil off as experience. I like linkages, I have one under my swingarm. they work great. Check out Dave Winship's multipoint linkage doc. on the INOA Yahoo site. (Files).

You're right, that's exactly what will happen, it will bend, or be deflected out of square. You can get packs of various thickness sheets of stainless shim material to shim up the mounts under the plate where you need it. I think this is where the added vibration with this mod has come from.

I had plates made out of 3/16" stainless. Lapped flat, polished. Turned down the mounting bolts on a lathe to keep them away from the tank, ect... If you enjoy fettling, it's fun to get it right. In my view, this headsteady is to Amal's what Dave Taylor's headsteady is to Mikuni's. The Mikuni is a quantum leap up in design and execution. You'd have to be some kind of Luddite to ignore the advantages. Unlike Amals, (which have become a statement of fidelity to tradition), these don't even show. I have some issues with the design of Dave's unit. But in practice they work. To do it all over again, I'd get a Taylor headsteady and write the Norvil off as experience. I like linkages, I have one under my swingarm. they work great. Check out Dave Winship's multipoint linkage doc. on the INOA Yahoo site. (Files).

Click to expand...

Hi Bob interested in your side plate mod am I being dumb :? but with the increase in side plate thickness how do the nuts contact the two tubes in the rubber doughnuts I guess you milled out the thicker plate so the nuts are recessed ?

plj850 said:

Hi Bob interested in your side plate mod am I being dumb :? but with the increase in side plate thickness how do the nuts contact the two tubes in the rubber doughnuts I guess you milled out the thicker plate so the nuts are recessed ?

Click to expand...

Hi PLJ850, The increase in thickness has no effect on the orientation of the plate to the rubber tubes and the mounts. I did give up a few threads on the main stud, but I think I turned it down when I was using the thinner plates. In any case it's been sufficient. In inside face of the plate is very smooth and even.

bpatton said:

plj850 said:

Hi Bob interested in your side plate mod am I being dumb :? but with the increase in side plate thickness how do the nuts contact the two tubes in the rubber doughnuts I guess you milled out the thicker plate so the nuts are recessed ?

Click to expand...

Hi PLJ850, The increase in thickness has no effect on the orientation of the plate to the rubber tubes and the mounts. I did give up a few threads on the main stud, but I think I turned it down when I was using the thinner plates. In any case it's been sufficient. In inside face of the plate is very smooth and even.

Click to expand...

Thanks Bob I was being dumb :roll:

Hi Bob Patton, I noticed an extra vent on top of your inletvalve cover. What benefit does it give? What is the inside bore? Where does the tube end? Thanks