As well as supporting the gear spindles and retaining the gears, the outrigger plate carries a bronze bush that is fitted to support the outer end of the crank...
This bush and the shoulder of the crank pinion wear over time. The outer end of the bush is also frequently worn if the drive side bearing spacer has worn and allowed the crank to move too far towards the drive side...
The bushes are still available and should be replaced if worn...
The bush itself is a press fit into the plate (.0015"-.0035" interference)..
It is also held in place by two mild steel rivets...
The countersunk heads of these rivets have to be drilled and then the rivet shanks can be removed using a hammer and suitable punch..
Likewise with the bush once the rivets are removed, or it can be pressed out.
The new bush must then be pressed in...This process distorts and compresses the bush so it should be honed or reamed after fitting to give a .003"-.005" clearance on the shoulder of the crank pinion..I generally aim for the lower tolerance.It is best to measure the crank pinion shoulder using a micrometer to calculate the actual size of the bore of the bush (with the tolerance applied) as the shoulder may well also have some wear present....
Riveting the bush can be an awkward process if a good final result is to be achieved...
I fit screws to the bush and plate to circumvent this process....
Two 3mm countersunk screws of the correct length are are suitable for this job, having the correct size heads to suit the bush flange...Drill and tap the bush and plate to 3mm, taking care to position the holes so that they do not interfere with the existing holes in the plate previously used for the rivets.
Then drill the bush flange on the rear of the plate to a clearance size for the screw...Next countersink the bush flange so that the heads of the screws are not 'proud' of the surface when fitted...
A dab of Loctite 'threadlock' on each screw prior to fitting will prevent them moving after being screwed home and that completes the job...Ian
email (option): ian@wright52.plus.com
They'll run whatever size the hole in the bush is and whatever the clearance is, as long as it's not too tight...
Whether that is a good thing or not is up to the individual I suppose...
That applies to many things on the bike, for example, the valve springs, fork spring, anti drain valve spring, rear brake arm bushes and sleeve, brake cam pivot holes, cam spindles and bushes etc. etc...
Many of these are rarely replaced or refurbished because they still function, despite being beyond the recommended tolerances...
Personally, I try to restore everything to the correct specification wherever it's possible and practical....Ian
email (option): ian@wright52.plus.com
Here's one I did earlier and one from the shrapnel box for comparison..
...Ian
email (option): ian@wright52.plus.com