Box type head steady on 72

staticmoves · Jul 19, 2012

So I have installed the 850 box type head steady with spring.
My question is, what kind of load or tension am I supposed to put on the spring?

Thanks in advance...... 8)

Ron L · Jul 19, 2012

According to the manual, 1.47-1.53 inches measured at the spring coils.

staticmoves · Jul 19, 2012

Ron L said:
According to the manual, 1.47-1.53 inches measured at the spring coils.

So the coils should be stretched to measure 1.5" ?

lbridges · Jul 20, 2012

staticmoves said:
Ron L said:

According to the manual, 1.47-1.53 inches measured at the spring coils.

Click to expand...

So the coils should be stretched to measure 1.5" ?

Yes, but not with the bike on the center stand (assuming the '72 stand is anything like the '75).

L.A.B. · Jul 20, 2012

staticmoves said:
So the coils should be stretched to measure 1.5" ?

But first, fit the spring correctly, so the open ends of the trunnion hooks are facing forward.

staticmoves · Jul 20, 2012

Thanks guys, I will switch the spring around the other way tonight.
So when I get this bike running, it will be my first ever ride on a commando. So besides the original 72 head steady cracking, what are the advantages and performance differences of the box type head steady and spring setup over the original for 72.

grandpaul · Jul 20, 2012

The spring is designed to suspend the weight of the engine in a more favorable attitude with regards to the front and rear isolastics, so as to "unload" them to a nearly neutral position, thereby relieving the static burden that eventually squashes them. In use, they should wear much more evenly and do a more proper job of isolating thier respective loads.

staticmoves · Jul 20, 2012

grandpaul said:
The spring is designed to suspend the weight of the engine in a more favorable attitude with regards to the front and rear isolastics, so as to "unload" them to a nearly neutral position, thereby relieving the static burden that eventually squashes them. In use, they should wear much more evenly and do a more proper job of isolating thier respective loads.

Thank you GP for the excellent product and enlightenment. 8)

DogT · Jul 20, 2012

My 69 does not incorporate the spring and I notice the iso mount collar does not line up with the end cap, front or rear. The front droops and the rear is skewed towards the rear. I have plans of installing the spring somehow, even if I have to make one of the rose joint head steadies. My original donuts were pretty oblong from the sag.

static, if you get a chance, I understand the spring mount (actually the bolt part that mounts on the head steady) on the engine is offset from the engine center line. If you could get me that measurement, perhaps in relation to the 3 Allen bolts in the head that would be wonderful.

Dave
69S

L.A.B. · Jul 20, 2012

DogT said:
I understand the spring mount (actually the bolt part that mounts on the head steady) on the engine is offset from the engine center line. If you could get me that measurement, perhaps in relation to the 3 Allen bolts in the head that would be wonderful.

The spring mounting bracket is centred on the box section.

The angled plate part of the steady is not symmetrical, consequently all three mounting holes are offset to the left by 1/8" (the large access hole makes it look more than 1/8" as the difference in the dimensions each side of the hole is twice the offset). I've found 1/8" isn't quite enough to suit my Mk3, which needs around 3/16" offset, the extra 1/16" is obtained by adding shim washers to the two studs between the right side plate and the steady. If the steady isn't shimmed, then the steady still fits because the elongated holes in the plate will allow for the misalignment but the steady will be skewed at a slight angle to the frame.

1up3down · Jul 20, 2012

The absolute best head steady I have employed was the Dave Taylor with the optional Mark3 spring set up.

For less than $200 including the spring, I felt it was cheap, and very effective because it not only helped to lift the motor with the spring but also the rod linkage prevented the motor moving side to side but allowing rotation up and down and forward and aft.

The DTHS with the spring is THE best way to go for the money, I feel.

DogT · Jul 20, 2012

I've given serious thought to the DTHS, but for some reason, I just don't like the way it mounts. It's just me. I'd rather make a rose joint setup myself, plus it gives me something to do.

So the box part of the HS (that attaches to the frame mounts) is centred on the frame, so the spring pulls straight. It's the part of the HS that attaches to the engine that's offset by 1/8-3/16". That's what I'm understanding you are getting at L.A.B.?

Thanks,
Dave

L.A.B. · Jul 20, 2012

DogT said:
So the box part of the HS (that attaches to the frame mounts) is centred on the frame, so the spring pulls straight. It's the part of the HS that attaches to the engine that's offset by 1/8-3/16". That's what I'm understanding you are getting at L.A.B.?

Yes, apparently.

Also, I don't know if this is true for all, but the width of the two Metalastiks plus the frame tube of my Mk3 is a total of 2.8". The width of the box section is 2.5" so in order for the two side plates to be fully tightened down against the box section, the Metalasiks must be compressed by 0.30"

DogT · Jul 20, 2012

Metalastics being the rubber isolators with the studs sticking out? As I remember my 69 head steady bracket has no offset to it, but I do know the engine sits off to one side at least it appeared to. I guess I'll have to pull off the tank and take a look see and measure the widths of things there. It's too hot and humid for anything else, plus it's raining for a few days.

Dave
69S

DogT · Jul 20, 2012

I was wrong. My early head steady is offset to the left by 11/64" at the engine side. I took the whole assembly off, and it appears that the rubber isolators are real close to the width of the attachment on the head steady, within .005". And setting it in place with the 3 Allen screws loose, it appears that it is pretty much in the centre adjustment of the head slots when I tighten down the side brackets on the rubber isolators.

I attached the spring assembly, less the threaded part which I don't have and also nothing to attach it to. I'm thinking I'll make a bracket, weld a threaded bolt to it, attach it under the centre head bolt and see what kind of engine pull up I get at the front and rear isolastics when I stretch the spring to 1.5". Just for a test to see if it will pull up the front and rear isolastics to get them anywhere near centred. I don't want to stress the centre head bolt and pull it out by riding it that way.

Does the spring go over the first or second rise on the spring keeper at the top?

I may do a separate thread not to hijack this one which I've already done. This is all in anticipation of the DIY Keith head steady.

Dave
69S

lbridges · Jul 20, 2012

DogT said:
...

Does the spring go over the first or second rise on the spring keeper at the top?
...

Seems to vary - the main idea is to obtain a spring length of 1.5". If the earlier model engines/gearboxes weigh significantly less the distance should be scaled linearly (springs have a linear force over most of their elastic travel limits).

The MK3 text on engine removal states "...Detach the suspensory spring stirrup from the coil-bracket, noting which notch locates the loop of the spring (usually this is on the forward notch) lift off spark plug caps, then remove the coil cluster complete from the frame..."

L.A.B. · Jul 21, 2012

DogT said:
My early head steady is offset to the left by 11/64" at the engine side.

Dave,
Where did you take those two measurements? If 11/64" (0.172") is the difference then the offset will be half that amount.

nortonspeed · Jul 21, 2012

1up3down said:
The DTHS with the spring is THE best way to go for the money, I feel.

If you forget about the money the CNW headsteady excels the Dave Taylor headsteady: same design but much stronger and self lubricating joints (disadvantage very expensive!).

DogT · Jul 21, 2012

L.A.B. said:
Dave,
Where did you take those two measurements? If 11/64" (0.172") is the difference then the offset will be half that amount.

Yes, I measured to roughly the center of the center hole from each side of the clipped on rulers, so lets make it 11/32" offset. Looking at the motor from above the frame it's pretty obvious.

nortonspeed said:
If you forget about the money the CNW headsteady excels the Dave Taylor headsteady: same design but much stronger and self lubricating joints (disadvantage very expensive!).

Yes, I like the way CNW does theirs.

Dave

VintAge · Jul 21, 2012

DogT said:
L.A.B. wroteave,
Where did you take those two measurements? If 11/64" (0.172") is the difference then the offset will be half that amount.

Yes, I measured to roughly the center of the center hole from each side of the clipped on rulers, so lets make it 11/32" offset. Looking at the motor from above the frame it's pretty obvious.

I don't think you actually mean 11/32" Dave, since that is double 11/64". Half would be 11/128" (.172 / 2 = .086 = 11/128) . Less than 1/8" assuming the original measurements are accurate.

Box type head steady on 72

staticmoves

Ron L

staticmoves

lbridges

L.A.B.

Moderator

staticmoves

grandpaul

staticmoves

DogT

L.A.B.

Moderator

1up3down

DogT

L.A.B.

Moderator

DogT

DogT

lbridges

L.A.B.

Moderator

nortonspeed

Guest

DogT

VintAge

Similar threads