Author Topic: Front fork rebuild.  (Read 5162 times)

Online a101960

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Front fork rebuild.
« on: 13.04. 2010 18:24 »
Well, finally the job is done. Some of you might remember me asking for advice before I embarked on this little project. For the benefit of the uninitiated this not a task that is as easy or straight forward as it would appear to be. If you have carried out a fork rebuild without assistance then you have my deepest respect. Dismantling was a fairly simple matter because I went to the expense of buying the correct BSA service tools and it was money well spent. The bearing cone remover made the task of removing the cones nice and easy but you also need a substantial piece of round bar to reach through the headstock before you can hit the tool. I know that it might be stating the obvious but if you do not have a piece of bar to hand then the actual tool is of little use. Fitting the taper roller conversion was straight forward. I made a tool for pulling the bearings into the headstock by fabricating to discs that were placed over the bearing cups and was thus able to pull them into place by tightening up a stud that ran through the centre of the discs.

The fork legs turned out to be a bit more problematic. Well, you can't have everything going right can you? Where is the fun in that! The fork legs came apart easily enough once the circlips had been removed. In went the new stanchions and bushes (which were bought as a matched set by the way) with no problems. I also took the precaution of buying a set of shims which I did not need, but you all know how it is don't you? If I had not bought the shims I most certainly would have needed them.  With all the new parts assembled the ciclips were fitted and the gap between the bush and circlip was measured with a set of feeler gauges. No Gap was found. Hooray! that made life a bit easier. I must just mention here that fitting the ciclips required the resources of three people to get the job done, and even then the clips broke free and went flying off in all directions two or three times. (and yes I did buy a spare set of circlips just in case). The stage was now set for the oil seal holders to dish out some grief. The Oil seal fork holder tool would not slide into the new holders (a point to bare in mind with pattern parts). So the tool needed a bit of attention to rectify this issue. The tool was fine by the way it was the holders that were slightly under size. The legs then went back onto the bike along with a pair of progressive springs and a pair of Eddie Dow dampers. I wish I could say that, that was that, but there was more. The wheel spindle (8" single sided brake) was a bit tight coming out on disassembly and it proved to be even tighter on refitting. Why? I still don't know. Anyway, a bit more grief. So I then decided to replace the wheel bearings and spindle but of course it wasn't as easy as that. You are know doubt ahead of me here, Yes? the bearing retainers were substantially mutilated (some previous owner). Eventually they were freed off (but it was touch and go). More expense! A new set of retainers were ordered and again the appropriate BSA service tool to do the refit properly and on receipt of these items everything was put back together, and strange to relate, the wheel went back into the forks without further drama.

Time to try and set the forks up then. The correct grade of oil was added a quick pump or three on the forks to align everything up. Clonk, clonk, clonk! What was that? A quick look around revealed that I had not tightened the brake plate torsion arm. Try again. Everything is fine this time.

The good news is that it has been well worth all the aggravation. I really had no idea how bad the forks actually were until I went out for a test ride. The forks are now smooth and silent in operation. I freely admit that it was the fact that the oil seals were leaking that initiated the fork overhaul and if the seals had not leaked I would have been none of the wiser, naively accepting as fact the old wives tale that all old BSA forks rattle and clank a bit. In conclusion if anyone tells you that "they all do that sir" when the subject of clanking BSA forks gets a mention I can tell you that it simply ain't true.


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Re: Front fork rebuild.
« Reply #1 on: 04.05. 2010 15:02 »
nice job a101960
I'm VERY new to mechanics but have done the forks on my '69 Royal Star & my '50 Indian Chief.
Unfortunately I didnt have any of the BSA tools but I wish I did.
well done

Offline mikethebrush

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Re: Front fork rebuild.
« Reply #2 on: 14.06. 2010 12:00 »
im pleased you posted this as onr of the jobs I need to do is replace the oil seals