FRONT FORK SPRING REPLACEMENT
A few days ago, I began to notice the D7 front forks were becoming very noisy and seemed to 'bottom out' at the slightest undulation in the road surface (of which, near me, there are plenty!)
It got so bad I realised all was not well so decided to do a strip down in order to discover the problem! And what follows is how I went about it and what I found! 1 Raise the bikeI always find it much easier to remove the front wheel if I raise the bike up first, by placing a couple of bricks under each foot of the centre stand.
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2 Remove the brake cableSlacken the brake cable adjuster, then undo the nut and bolt securing the cable to the brake cam lever (90-5713) and withdraw the cable assembly, fastening it to one side out of the way.
3 Remove the front wheelPut a suitable-sized block of wood under the front wheel, then slacken the brake plate locking nut (2-449) and undo and remove the bolts (90-5240) under the sliding tube caps (90-5239) on each side to free the wheel spindle.
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Remove the block of wood, lift out the wheel and put to one side.
Next, undo the two mudguard clips (90-6541) and let them drop down the fork tubes. Then, undo the two mudguard bracket nuts on each fork drain plug. You may, if you prefer, remove the plugs and let the oil squirt out! However, it makes such a mess I prefer to leave it until I have removed the springs and can drain the tubes into a suitable container. But, as I say, it's all down to individual preference. |
4 Remove the spring assemblyPrise out the two chrome-plated top nut caps (90-5255) and put them to one side.
For this job, I did not find it necessary to disturb the two shafts (stanchions), so leave the large chrome nut well alone. Then, using a suitable socket (I used one I'd ground downspecially as there's not clearance) undo the top nuts (42-0101) and remove them. The spring assembly should now just fall away from the top and hang, held in place by the oil seal collars. |
5 Separate the spring assembly from the shaftsBefore you can separate the spring assemblies from the shafts, it's necessary to undo the two screwed collars (90-5246) containing the oil seals.
Mine undid fairly easily, although three hands are better than two! However, if all else fails, it may be necessary to remove the stanchions as well (by undoing the two large top nuts (90-5251 and bottom yolk pinch bolts (21-5672). It may also be necessary to help break the seal in the yolk by tapping the large top nuts before removing them altogether (small hammer though!). |
If you're successful - as I was - this will leave the screwed collars, upper and lower bushes (90-5230 & 90-5229) still on the shafts, whilst the spring assemblies will have been separated, although still joined to the fork sliding tubes (90-5232 & 90-5235) by the restrictor rods (90-5249).
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6 Dismantle spring assemblyAfter draining the oil out of the tubes, grasp the springs and rotate anti-clockwise to undo the restrictor rods from the inside of the tubes.
It will be necessary to hold the spring assembly securely in a vice, as you will need to unscrew the spring anchorage (90-5244) from the top end and the restrictor rod (90-5249) from the bottom end of the spring. |
Both of these components can prove quite stubborn to undo and a degree of force will be required!
I found my mole wrench came in handy, although I had to get them started using a suitable drift and tapping gently with a small hammer! The same will apply when refitting to the new springs. Please note: the new springs do not come with the anchorage or restrictor rods attached! |
7 This is what you're left with!Row 1: two mudguard clip nuts and bolts; one brake cam lever bolt; two top nut caps.
Row 2: restrictor rod; spring anchorage; top nut. Row 3: restrictor rod; spring anchorage; top nut. Row 4: two sliding tube end caps; four bolts. Row 5: sliding tube,RH, with mudguard clip. Row 6: sliding tube,LH, with mudguard clip. |
8 And this is what I found!As soon as I removed the offside spring and sliding tube assembly I knew something was wrong.
The offside spring had broken at the restrictor rod end, leaving just an inch or so still attached!
As the springs needed to be replaced as a pair, I ordered a new set from NSA Classic Bikes and they arrived a day later! Great service, as usual - with many thanks to Nick Avery! |
9 Now for the tricky bit!Fitting the springs to the restrictor rods and anchorage proved a bit tricky.
Once I'd dressed the ends of the springs to remove the burrs it was much easier, although I still needed to use my mole wrench.
Half an hour later and that job was done! And here's the finished result. |
10 Reassembling the springsNext we have to insert the springs, restrictor rod end, into the sliding tubes and screw them in tightly.
I found it easier to clamp the tubes in the vice then, with a bit of patience, the spring/restrictor rods should screw in (clockwise).
Be prepared to have a few goes at it, though, as it is fiddly! |
11 Filling up with oilAt this point I measured out a quantity of oil (75cc of 20w per leg seems to work well for me and gives a reasonably comfortable ride!).
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Using a small funnel I slowly poured 75cc into each tube.
The Haynes manual shows the oil being poured in from the top after refitting, but, in my experience, this takes forever! |
12 Grease the bushes and sealsBefore inserting the spring assembly back inside the stanchions, I always grease the bushes and oil seals in their holders.
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13 Job almost done!You'll find you can easily push the completed assembly up to the top of the stanchion, until the anchorage stud appears.
Then it's just a case of inserting the top nut and screwing it on loosely ready for tightening. |
And finally...Refit the mudguard, then the wheel, and reconnect the brake cable.
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Once everything is back together again, give the front forks a good bounce up and down to ensure everything is in alignment.
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The, retighten the top nuts fully and all the other nuts and bolts.
Take the bike for a test ride, then check for tightness again.. |
Once again, Nick Avery at NSA Classic Bikes is an excellent sourse of spares for BSA Bantams as well as other marques.
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