Steering head nut on 76 T140V
- Thread starter Brhino
- Start date
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B, give us a little more info. what position have you got the nut in, it's not crossed threaded is it?
This is completely wrong for any pre-Hinckley Triumph.
By "steering nut", you mean the one with the large hex in the centre of the top yoke (aka "triple tree")? If so, are you seeing a gap between the underside of the nut hex and the top of the yoke, and you are trying to tighten the nut to remove the gap? If so, that would be wrong, there is supposed to be a gap there, otherwise either the steering bearings are worn out or the forks have not been assembled correctly.
Please clarify which "steering nut" you actually mean.
Which nut is the problem?
The one holding the handlebars!
hee hee
(couldn't help myself)
That nut should have a gap between the underside of the hexagon and the top of the upper triple tree.
Your photos show an oil-in-frame and pre-'79 disc brake upper triple tree, so your bike is a '73-'78 750 or 650?
That nut screws on to the steering stem. Be aware the steering stem is only an interference fit in the lower triple tree so, if you had used "a 3-4ft breaker bar", you would likely have pulled steering stem and lower triple tree apart ...
If you do not have a parts book for your bike, you can read it online at British Only Tech Library
Be aware one error in the parts books - parts #11 "83-2007 Abutment ring" and #13 "97-4028 Dust cover" are transposed, #11 is the "97-4028 Dust cover", #13 are the "83-2007 Abutment ring" illustrated below the upper bearing and above the lower bearing.
Your bike has taper roller steering bearings in the frame. Each bearing was/is in two parts, the part without the rollers was a tight fit in the frame; you fitted the upper bearing "Abutment ring" and then the race with the wider opening upwards, you fitted the lower bearing "Abutment ring" and then the race with the wider opening downwards; both races were pressed into the frame until each "Abutment ring" reached a smaller diameter inside the frame steering head.
You greased both bearings taper rollers, you fitted the lower taper rollers over the steering stem to the lower triple tree, you dropped the upper taper rollers in the upper race, you fitted the steering stem through the lower bearing race and the complete upper bearing, pushed up the lower triple tree until the lower taper rollers reached the lower bearing race in the frame. You fitted the "Dust cover" over the steering stem on to the upper steering bearing, the upper triple tree over the steering stem on to the "Dust cover" and finally screwed the "steering nut" on to the steering stem thread.
You saw the steering nut passed through the upper triple tree. Did you ensure the steering nut also passed through the "Dust cover"? The bottom of the steering nut must bear on the upper steering bearing.
However, while your photo shows the upper triple tree and steering nut fitted, it does not show the standard covers over the fork stanchions. If you are intending to fit these covers to mount the headlamp and ignition switch, you should fit them before adjusting the steering ...
When you turn the steering nut clockwise, because it bears on the upper steering bearing, but that bearing cannot move any further down into the frame, the nut pulls the steering stem upwards. The steering stem pulls the lower triple tree upwards, the lower triple tree pulls the lower bearing rollers upwards into the race. That race cannot move any further up into the frame, then continuing to turn the steering nut clockwise simply applies more friction to the two steering bearings until the forks become immovable.
Here is the skill adjusting taper roller steering bearings - the steering nut must remove all 'play' - forward-back-side-to-side movement - between rollers and races but not apply any additional friction between rollers and races; the forks must turn easily lock-to-lock without stopping particularly/repeatedly at any point in between.
When steering adjustment is completed, as above, the "steering nut" should have a gap between the underside of the nut hexagon and the top of the upper triple tree.
Reasons it might not:-
. Something wrong with the the steering bearings. New ones might be thinner than originals, you might have damaged the ones on your bike tightening the steering nut too much; old ones worn out.
. The upper triple tree is not sitting on the upper bearing dust cover. Original Meriden-made stanchion covers did not prevent the upper triple tree sitting on the bearing dust cover; modern pattern stanchion covers are not always made so accurately.
However, if new stanchion covers are as much as 1/4" longer than the originals, you have been supplied the wrong covers, they are for a "dry frame" (separate oil tank) Triumph.. Another reason the upper triple tree is not sitting on the upper bearing dust cover can be the steering adjusted without ensuring both triple trees can slide easily over the stanchions:-
.. When adjusting the steering bearings as in your photo - many other fork parts not fitted - ensure the stanchions are loose in both upper and lower triple trees, because steering bearing adjustment might move the the triple trees vertically slightly, either closer together or further apart.
.. When fitting other fork parts - particularly each stanchion's "Top nut" and "Cap screw" - and adjusting the stanchion height to clamp speedometer and tachometer between those two parts, be careful not to affect steering adjustment because the upper triple tree is clamped to the steering nut.
.. If/when adjusting the steering bearings with all fork parts fitted, loosen only the lower triple tree stanchion clamps to allow for any vertical movement between upper and lower triple trees; this will prevent either speedometer or tachometer being raised by stanchion movement through the upper triple tree, or either speedometer or tachometer restricting vertical triple tree movement.
The torque setting is for the nut and bolt through the steering nut clamp in the upper triple tree, that holds the steering nut in the set position. In practice, even that torque isn't necessary, just as long as the nut and bolt are tight.
