Head steady fitting

johnny Lagdon · Sep 26, 2020

Refitting a standard 850 box section head steady to a '73 850 bike that had sat for 10 years. I have replaced both m,ain iso's and have new rubber bobbins that screw into frame. when you sight down the flat of the bobbins to the sides of the deady steady box section, they do not line up, and the discrepancy either side is not equal. As my other bikes have after market head steadies I have no experience of fitting a standard one. should I add shims/spacers to get things to line up when the side plates are fitted?

Torontonian · Sep 26, 2020

The engine does not sit dead center to the backbone when viewed from above. Normal so the head steady plates are to the left a tad. There was a thread where it was discussed.

johnny Lagdon · Sep 26, 2020

Thanks, I have clearance both sides of the side plates when mounted to the screwed in rubber bobbins. Seems to me that there should be some kind of spacers or shims to make them level with each other, or when you tighten the nuts on the through studs it will distort the rubber between the bonded steel plates and prematurely damage them.

grandpaul · Sep 26, 2020

Do you have the spring & saddle rig? Proper tension on it BEFORE installing the bobbins, might be the best course of action, unless it's contrary to the shop manual...

johnny Lagdon · Sep 26, 2020

grandpaul said:
Do you have the spring & saddle rig? Proper tension on it BEFORE installing the bobbins, might be the best course of action, unless it's contrary to the shop manual...

No, but i cant see that the MK3 saddle and spring gizmo would make any difference to the air gap that exists in 2 parelel planes 90 degrees to fore and aft which is the pull of the suspensory spring device. the box section is 2 33/64" wide, and with the bobbins seated in the frame threaded lugs and the side plates mounted they are 2 23/32" apart. This leaves a gap of 13/64" distributed between the 2 sides.

Fullauto · Sep 26, 2020

Throw it where it belongs. Get the CNW head steady. Far superior.

SeeleyWeslake · Sep 26, 2020

The difference between fat & skinny bobbins?
IE there have been different width bobbins sold by various suppliers over the years.

kerinorton · Sep 27, 2020

Before making and fitting my Ludwig style head steady , I used to make sure those rubbers were equally under compression. You can add washers between the bobbins and the brackets.
Those brackets can bend though.

kommando · Sep 27, 2020

RGM do bobbins that match the original size, a lot are too narrow.

Peter R · Sep 27, 2020

kerinorton said:
Before making and fitting my Ludwig style head steady , I used to make sure those rubbers were equally under compression. You can add washers between the bobbins and the brackets.
Those brackets can bend though.

Can you please explain the Ludwig style head steady ?

gortnipper · Sep 27, 2020

Peter R said:
Can you please explain the Ludwig style head steady ?

L.A.B. · Sep 27, 2020

johnny Lagdon said:
Seems to me that there should be some kind of spacers or shims to make them level with each other, or when you tighten the nuts on the through studs it will distort the rubber between the bonded steel plates and prematurely damage them.

johnny Lagdon said:
the box section is 2 33/64" wide, and with the bobbins seated in the frame threaded lugs and the side plates mounted they are 2 23/32" apart. This leaves a gap of 13/64" distributed between the 2 sides.

Tightening the nuts on the through-studs will compress the rubber mounts slightly as the plates will tighten down parallel to each other and I've never known it to damage the mounts.
It does mention in Norton Service Release N3/51 that tightening the fittings pre-loads the rubber mounts.

B+Bogus · Sep 27, 2020

Leave all the fasteners loose until it's all assembled.
When fitting my DT headsteady I had fun discovering just how much the motor can move by sitting on the bike with the stand up and leaning it left & right.
When the bike is on the centrestand the motor is already under stress, and not sitting in its neutral state.
Agree that the standard headsteady isn't the best, but Johnny is already familiar with that, I suspect

johnny Lagdon · Sep 27, 2020

B+Bogus said:
Leave all the fasteners loose until it's all assembled.
When fitting my DT headsteady I had fun discovering just how much the motor can move by sitting on the bike with the stand up and leaning it left & right.
When the bike is on the centrestand the motor is already under stress, and not sitting in its neutral state.
Agree that the standard headsteady isn't the best, but Johnny is already familiar with that, I suspect

Your suspicions are well founded!

grandpaul · Sep 27, 2020

johnny Lagdon said:
...I cant see that the MK3 saddle and spring gizmo would make any difference to the air gap that exists in 2 parallel planes 90 degrees to fore and aft which is the pull of the suspensory spring device. the box section is 2 33/64" wide, and with the bobbins seated in the frame threaded lugs and the side plates mounted they are 2 23/32" apart. This leaves a gap of 13/64" distributed between the 2 sides.

The spacing should be correct, or not off by much, unless the rubber buffers are REALLY bad knock-offs.

The spring has a specific purpose, and is beneficial to ANY head steady, for the job it does.

kerinorton · Sep 27, 2020

Thanks David. Your onto it.

Dereck

Head steady fitting

johnny Lagdon

Torontonian

johnny Lagdon

grandpaul

johnny Lagdon

Fullauto

SeeleyWeslake

kerinorton

kommando

Peter R

gortnipper

L.A.B.

Moderator

B+Bogus

johnny Lagdon

grandpaul

kerinorton

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