Dismantling the fork

Started by Thomas, May 19, 2018, 06:01:01 PM

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Thomas

Wow, great description, Rick. You are not too late because I will postpone this work. But it's definitely a great help.
Cheers, Thomas
1946 BSA C11
1937 Sunbeam Model 9
... and a scratched Hyundai
(MSCR member)

Rick Parkington

Hi Thomas,
Maybe you've worked it out by now but just in case you haven't...
I usually find it is easiest to remove the top and bottom links from one side - the spindles usually screw into the link on one side for adjustment while on the other the link has plain holes and is just pushed on to the link and secured with a nut. I'm not sure which fork you have but on the 1932 dogleg type, the link to remove at the top is the side with the friction damper and at the bottom the side where the thread is almost completely covered by the nut - the other side having adjustment thread sticking out from the nut. On my bike these are on the right side as you sit on the bike.
Support the bike under the crankcase/footrests or anything secure that puts the weight onto the rear wheel and remove the front wheel/mudguard/electrical wiring/control cables or anything else connecting the forks to the bike then remove the link nuts/damper assembly. Slacken the top spring nut but leave in on for the time being. 
Next carefully tap the link outwards leaving the spindles behind - obviously if it really doesn't want to move, find out why rather than doing damage.
Once the two links are removed from that side, take hold of the front fork girder and tap the other side links - or use a soft drift on the spindle ends - and remove them, one at a time, complete with spindles. If you remove the top first, watch that the front fork doesn't cantilever around the bottom spindle to bash into the frame, that's why you should hold it...
The fork is now only attached by the spring, having already loosened the top nut (I usually forget and have to support the fork while doing some yoga move to reach a spanner!) you can slide the spring out of the top yoke lug and remove the girder, leaving the yokes and head bearings still assembled for further attention.
'Reassembly is the reverse...' as they say. Doing it this way means you don't have to compress the spring to fit or remove it because the fork is fully extended. You can get trouble on some forks with the fat bit of the spring binding on the frame at full extension which aside from scratching paint can mean when you put it together the stud doesn't want to line up to pass through the hole in the top yoke easily; worst case there is that you have to take off the top yoke, insert the spring and reassemble.
If it can all go straight back together then the other good thing is that, with these type of forks at least, you haven't disturbed the adjustment of the spindles. If these need attention it is fairly straightforward, back off the friction damper and make sure they bounce nicely up and down but grip the front wheel between your knees and waggle the bars to make sure there's no slop between the girder and links. Some bikes provided handy knurled washers in the join so you know to tighten them so as you can still turn the washer but without rattle but i haven't had these on a Sunbeam.
The only problem I recall with my '32 9A was that having set the adjustment, it stiffened as I tightened the locknuts, so I had to use trial and error, keep backing off a quarter turn and locking it up until it was right. That said I built the bike 15 years ago, have ridden it all over including from Edinburgh to the Isle of Man three times (and slid it into a wall!) and they haven't needed adjusting since the original shakedown.
Final point: you cannot have too much grease. I replaced the original nipples with modern type (well, 1950s on - of course I have kept the originals). This makes it a quick job because the old push on grease guns tend to be more of a faff to use (and to fill) than the snap fit type and I like to make sure the grease really gets in there; pumping until it squeezes out of the joins. Reconditioning girder forks is a difficult and expensive job so it pays to keep them well greased. Admittedly it's likely to spit out occasional gobs of black grease onto the tank, headstock and possibly rider - which may explain why a lot of shiny bikes don't seem to have seen a grease gun since they were restored but it wipes off...sort of!
 
Blimey, sorry for the long post - hope it's helpful!
Cheers Rick

Thomas

Hello all!
I need to detach my girder fork. Is there a specific procedure to follow or is there something difficult to deal with? Do the bushes and axles need special care? I can only imagine that the central spring is difficult to detach and put back into place again.
Cheers, Thomas
1946 BSA C11
1937 Sunbeam Model 9
... and a scratched Hyundai
(MSCR member)