Norton Commando Remove Fork Tubes
Article and Pictures by Mark Trotta
Although the most common reason for removal is to replace leaking seals, the fork tubes on this 1974 Commando were badly pitted from years of sitting and needed to be replaced.
This article details fork tube removal on 1972 and later Commando models.
To read about how to disassemble forks click here.
To read about how to assemble forks click here.
Getting Started
Removing the tank prevents accidental scratching, plus a gives you little more working room.
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Brake Caliper and Master Cylinder
Disconnect the steel brake line, then remove caliper from fork leg.
This caliper was bone dry, so there was no worry about leaking brake fluid!
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Headlamp Removal
On each side of the headlamp is a bolt, washer, and spacer, which go through the left and right brackets.
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Prop Up Front of Bike
The front end needs to be propped up just enough so the wheel may be removed.
There are several options here, most common being a small floor jack under the engine.
Seeing as this bike was already half-stripped, it was light enough to lift up by the forks and rest on a piece of wood on a cinder block.
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Checking For Neck Play
With the front wheel off the ground, now's a good time to check if the steering bearings need replacement. In a crouching position over the front wheel, grab the forks, then push and pull forward and back. Even the slightest amount of play should be looked into. Also check side to side movement for any binding.
If you're going to be replacing neck bearings, the master cylinder and handlebars will need to come off.
A 7/32" Allen key is required to remove the handlebars.
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Front Wheel Removal
On the bottom of the right-side fork, remove the 5/16 x 1-1/4" pinch bolt. The right-side axle nut requires a 15/16" socket. The axle can be tapped through from the right side with a soft mallet.
An alternative way is to slip a large screwdriver through the left-side axle, grab the screwdriver with both hands, then twist and pull the axle out.
Front Axle Removal
Front Fender
Although you can remove it at any point, it's easier to remove the fender with the front wheel off.
There are four nuts (3/16 Whitworth), two on each side, that hold the fender onto the sliders. The two bolts that hold the fender stays to the fork sliders are 1/4 Whitworth.
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Pinch Bolts
On each side of the lower fork bracket are recessed Allen bolts. You'll need an 8mm or 5/16" Allen key to remove them.
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Fork Tube Removal
With a 33mm or a 3/4 Whitworth socket, unscrew the big top nuts. You will notice that they have internal and external threads. The fork damper rod screws into the bottom, and the external threads screw into the top of the stanchions.
Separate Damper Rod From Top Nut
With the fork springs exposed, unscrew and remove the top nut from the damper rod. A thin open-end wrench is needed for this.
This will allow for gauge cup removal.
These final steps are often the hardest.
How easy or how difficult the fork tubes come out often depends on how long the bike was sitting and how rusted they have become to the triple trees.
Re-install the top nut back into the stanchion. With a rubber mallet, smack the top of the big nut and hopefully the fork tubes will move.
If they don't move (many won't at first), try spraying with WD40, and letting them soak for a while.
If they still don't move, try a few more solid whacks with the mallet. If there's no movement - stop. Spray it with more penetrating fluid, let it soak overnight and try again tomorrow.
While removing the forks, they may get hung up on the rubber O-rings on the top and bottom of the headlamp brackets, which detach once the forks slide out of the triple trees.
Left and right headlamp brackets before cleaning.
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Drain Fork Oil
One of the oil drain screws was difficult getting out. Rather than take a chance of stripping out the original 50 year-old screw, I waited until the fork was removed and laid out on the workbench, which gave an easier vantage point. A fibre washer should come off with each drain screw.
The old fork oil was drained out into a pan, and can be recycled with old engine oil.
Read: Front Fork Disassembly
Read: Front Forks Overhaul
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