Vernier Adjustable Isolastic Head-Steady
Part Number 06-5459/A
Also available from British Cycle Supply:
Vernier adjustable isolastic head steady mounted on a bike
The body is cast aluminum, 356
T-6, that is milled to accept a rubber isolastic bushing. The three side plates
(inner, middle and outer) and the frame spacers are milled from aluminum, 6061
T6, bar stock. This head steady has been designed to allow for the differences
in the spacing from the top of the engine to the frame that occurs on Commandos
because of the different compression models.
If you do not make allowances for this spacing variance, you end up preloading the isolastic bushing. The isolastic bushing has a 1/2 x 20 Heli Coil insert the full length and the stud is bonded to the bushing by using 271 Loctite.
This makes the bushing, stud and vernier adjustment plates one piece and eliminated the slight buzzing in the bars that was experienced with the first version of head steadies. The bushing and stud assembly is pressed into the body and there is a PTFE washer between the inner and middle side plates. The middle side plates have Nylon lock nuts pressed into them providing the vernier adjustment.
The middle side plates are adjusted with the same size wrench (1 1/2") that you use to remove your crank case sump plug. A picture of the modified sump wrench is shown in Step 4 of the installation instructions. The modifications made to this wrench were to drill a 1/2" hole in the center bar, so the stud would pass through, and ground off a bit from the sides.
Assembled Head Steady
When you receive the head steady, remove the two 5/16 nuts and washers on the
inside of the frame spacers. These two nuts are not used to mount the head
steady, but you will use the two 5/16" stainless steel washers in Step 4.
Step 2: Remove the two lock nuts from the stud and the outer plates.
Step 3: For Commandos with the center stand mounted to the engine mounts, take your bike off the center stand and prop it up by using the side stand or something under the frame rails. For earlier Commandos that have the center stand mounted to the frame, you can leave the bike on the the center stand. As with adjusting your other isolastic mounts, you want the engine in a neutral position, not supporting the weight of the bike. Remove your old head steady saving your head steady screws and washers.
Step 4: Mount the head steady on your head using two of your head steady screws. Put one of the 5/16" washers removed in Step 1 down against the casting first, then the internal toothed lock washer and then the screw. This will protect the casting from the lock washer. Finger tighten the screws only on this step.
Step 5: Adjust the assembly to your desired spacing. When we assemble the head steady, we apply teflon lubricant between the PTFE washer and the inner and middle plates. This allows for more slippery surfaces and longer life of the PTFE washers. We also polish the sides of the inner and middle plates that press against the PTFE washer. When assembling, we tighten up the middle plates until we cannot rotate the middle plates by hand, then we back the middle plates to where we just get rotation. It is at this point that you can start to check for your desired clearance.
We have found that you will need to tighten the outer plates against the middle plates before you can accurately set your desired clearance. You do this by setting the initial clearance at around .025" to .030". Complete the assembly as described in steps 6 and 10. Tighten the two 1/2" lock nuts to around 30 ft/lb torque, then remove the two outer plates and set your final clearance. By setting a very loose clearance and torquing the end nuts, the head steady settles into its final position.
You can perform this initial torquing step and play with clearance settings in a vise with soft jaws or placing a couple of aluminum strips between the two end plates as shown in the above picture. You can use the same settings that you use on your other two isolastic mounts or do what we do and leave it at minimum clearance, but some rotation by hand is possible.
Step 6: Assemble the outer plates. Put one 1/2" washer in each of the indents of the middle plate. Put the outer plates in place and install one 1/2" washer over the stud, then thread the 1/2" lock nut by hand until it stops turning when the nylon insert is met.
Step 7: Insert the frame spacers between the top of the outer plate and the frame lugs. With the outer plate loose, you should be able to slide the spacer in from the front. Put the 5/16" washer on the 5/16" bolt and thread into the frame lug. Tighten this bolt just so it holds everything in place.
Step 8: Loosen the head screws that hold the head steady to the head a couple of turns so the head steady can freely move from side to side.
Step 9: Position the outer plates where you want them and torque the two 5/16" bolts to 15 ft/lb.
Step 10: Tighten one of the 1/2" lock nuts on the stud until it is holding the outer plate firmly making sure that the two middle plates do not turn. Normally one nut seems to thread easier than the other, so you can hold the harder to thread nut with a wrench and tighten the easier one. Once one nut is tight (tight so the outer plate is firmly against the middle plate) it is easy to tighten the other nut. Now torque both nuts to 30 ft/lb. You will have to torque both nuts, since they are tightening up against the middle plate and not each other.
Step 11: Tighten up the two head screws to the cylinder head. These head screws are 5/16", so no more than 15 ft/lb, because you are tightening them into an aluminum head.
The above procedure allows you to position the head steady in a neutral position where there is zero preload on the rubber isolastic buffer. You can adjust your settings to your particular riding style and may want to check them after a couple hundred miles in case the head steady settles a bit more.