Dual Disc Caliper Alignment Issue (not the usual) PART 1

[Ewan 500 K1]

An alternative suggestion from CrazyP on US forum for the left hand side, to what I was planning in the above post:
Reduce the length of the spacer on the left (nut) side of the spindle by 4 to 6mm , to bring the left hand caliper into line with the left hand disc (ie instead of shimming out the caliper bracket and/or making up a spacer to go between the hub and the disc).
The spindle nut may not then screw fully up to meet the shortened spacer, so would need to tap the spincle to make the threa for the nut longer ? Also it would only bring the bottom of the fork in a bit ... but the top would stil be in same place as dictated by the triple T clamp .. so doesnt really seem ideal ? This would result in the forks flexing inwards slightly .. would this matter ?

[Bryanj]

Ewan, the hub with two flats is the standard 500 hub same as 450 and 750, the hub without came along a lot later mate so somebody has been mix-n-matching prior to you!!!

[Bryanj]

Yup I'm certain as the Honda drive plate with the bent ears, as used on very erly ones, needed the two flats to drive off. The only reason i can think of for not lining up is if the forks changed when the hub did and/or something is fitted not quite far enough/too far/wrong place

[Ewan 500 K1]

acording to motogrid parts diagrams all three 500 models :

CB500 A MOTORCYCLE, JPN, VIN# CB500-1000001
CB500K1 A MOTORCYCLE, JPN, VIN# CB500-2000001
CB500K2 A MOTORCYCLE, JPN, VIN# CB500-2100001

share the same part number for :

Axle Collar (44311-371-980)
Axle (44301-425-870)
Bottom Yolk (53200-323-020B)
Speedo Drive Plate (44641-341-000)
Front Hub (44601-300-040)
but the front forks change from 51500-323-305 (left) and 51400-323-305 (right) to 51500-323-315 and 51400-323-315 at the introdction of the K1

But .. in my original CB500 / CB500K1 parts book the hub stays the same (44601-300-040) for both models but the speedo drive plate changes from 44641-300-020 to 44641-341-000. The speedo drive plate with the tangs for the hub mentioned in Brians document (44601-300-000) with the cut away flats is only for the 450K3 and 7750K0 according to motogrid.

CMSNL notes in the K1 parts list that the speedo drive plate 44641-300-020 is superceeded by  44641-341-000.  CMSNL also has the sme hub (44601-300-040) listed across all 500 models up to the K3 and the picture shown has the cut away flats on it on all models

I'm lost ! ... this may be a road to ..... I'll just bodge on and see what I can do to make everything line up .. almost finished getting the right hand side done bby putting the mudguard bracket on top of the caliper arm bracket instead of between the bracket and the fork , and taking about 2mm off the flat on the bottom of the caliper bracket pin... looks like I need to take a bit more off the pin.

[Ewan 500 K1]

the caliper arm pin top bracket changes at introduction of the K1 ... maybe thats the key difference that allows the narrower hub to be used

[Bryanj]

The forks change at the K1 as all the internals change and you no longer have the long threaded rod that screws into the damper at one end and the top nut at the other.

The top caliper piece superceeds to the later number so that fits all of them.

Are you sure the wheel bearing with screwed collar is all the way in to the shoulder as that would make a difference?

[Ewan 500 K1]

Are you sure the wheel bearing with screwed collar is all the way in to the shoulder as that would make a difference?

yep, bearing fully in.... but , eh but ... might have some developments tomorrow that might make my face red.. cue the wife chasing me about with the rolling pin for spending an inordinate amount of hours in the shed wasting time

[Ewan 500 K1]

Another day in the shed... a day of revelations.  What I found was that all three of my caliper arms have different numbers stamped on them. One has  5     5  stamped on it, one has 8    8 stamped on it and one has M2 stamped on one side and an 11 on the other. Of the three, one is distinctly asymmetrical in the vertical plane, ie it bends more one way than the other. The other two are symmetrical. Also, one is of thicker diameter than the other two at the end where the pivot pin goes through it. Also realised that the mudguard bracket is not the same as the one originally on the bike. So ... combination of narrower hub on 550 forks, different caliper arms and non standard muguard bracket seem to have thrown things well out. Spent all day messing about with different combinations of pivot arms, pivot pin brackets , placement of mudguard bracket ... and got there in the end . Now have a left and a right hand caliper each with a gap of 0.06 inch between the fixed pad and the disc and a freely rotating wheel.

On both sides the mudguard bracket is fitted as standard .. ie fork, mudguard bracket, pivot pin bracket on the right and fork, pivot pin bracket, mudguard bracket on the left.

On the right hand side I didnt need any shims or to file anything down to get it right in the end, just had to add some washers to the ajusting screw to give the spring some compression.

On the left hand side all I had to do was file down the leading edge of the pivot pin bracket (see photo 1).

The second and third photos show the calipers correcty positioned and adjusted. So, thank goodness , got there in the end

The only thing I'm now unsure about is the exposure of the speed drive plate (photo 4) ... is yours similarly exposed Bryan, or have you managed to keep the chrome cover ?

[Bryanj]

Cant have chrome cover and disc so mine must have looked the same, as i sold it in the late 70's early 80's i really couldn't tell you exactly!!

[Ewan 500 K1]

You don't retain the chrome cover, I seem to recall it no longer fits due to space constraints plus it would do nothing so why bother. You've put the folding tabs on the wrong side Ewan, the tabs go around the nuts not around the bolts, should be on the other side of the forks if you haven't already duplicated them. That was one of the functions of the chrome dish, it was shaped in such a way as to stop the head of the bolt rotating and the tabs on the standard disc side stopped the nuts from undoing. You can get the same effect now by using locknuts if you wanted but the tabs do make it look original.

I've got the folding tabs on both sides oddjob ... to make up for the fact that I dont have the chrome dish