Author Topic: Dual Disc alignment issue ... not the usual PART 1  (Read 3869 times)

0 Members and 2 Guests are viewing this topic.

Offline Ewan 500K1

  • Hot Shot
  • ***
  • Posts: 311
    • Adams Bros Probe 2001
Dual Disc alignment issue ... not the usual PART 1
« on: August 23, 2013, 01:43:14 PM »
Bit of a funny one when setting up my dual discs. The caliper arm for the additional disc on the right hand (speedo drive Side) was perfectly aligned with the disc without any need to mess around with shims or files contrary to all expectation (photo one) , but the original set up on the left hand side is misaligned (second photo) and had to be brought into line by putting some washers in between the caliper arm and the fork.... see photos 3 & 4 and close ups in next post. Anyone got any idea whats gone wrong ? . I have changed the wheel from the original.. maybe its that , see two posts down
« Last Edit: August 23, 2013, 01:53:22 PM by Ewan »
jings, crivens, help ma boab

500 four K1 cafe racer build thread at :
http://forums.sohc4.net/index.php?topic=100883.0

Offline Ewan 500K1

  • Hot Shot
  • ***
  • Posts: 311
    • Adams Bros Probe 2001
Re: Dual Disc alignment issue ... not the usual PART 2
« Reply #1 on: August 23, 2013, 01:47:45 PM »
Close Ups

1. Left side (usual side for standard single disc) from front
2. Left side from rear
3. Right side (side with aditional disc) from front
4. Right side from rear
« Last Edit: August 23, 2013, 01:54:42 PM by Ewan »
jings, crivens, help ma boab

500 four K1 cafe racer build thread at :
http://forums.sohc4.net/index.php?topic=100883.0

Offline Ewan 500K1

  • Hot Shot
  • ***
  • Posts: 311
    • Adams Bros Probe 2001
Re: Dual Disc alignment issue ... not the usual PART 3
« Reply #2 on: August 23, 2013, 01:52:21 PM »
1) Last time the bike was on the road , it had a single disc and ran fine with that. At that point it had 550k3 forks on and presumably 550 hub and axle

2) it still has the 550k3 forks but I used a different hub to build a new wheel. The replacment hub has the "flats" on it for the speedo drive . See pictures 1 & 2 for the old and new hubs

3) photo 3 shows the old and new axles and photo 4 shows the new axle with adapted speedo drive plate... adpated so that it has lugs to fit onto the "flats" on the hub.

Are the surprsing results from setting up the brake caliper likely to have anything to do with changing the wheel / axle set up. If not ... any other ideas out there ? ....... and .. does it matter anyway when I now have both calipers aligned with the discs anyway ?
« Last Edit: August 23, 2013, 01:58:10 PM by Ewan »
jings, crivens, help ma boab

500 four K1 cafe racer build thread at :
http://forums.sohc4.net/index.php?topic=100883.0

Offline iron_worker

  • Master
  • *****
  • Posts: 2,081
Re: Dual Disc alignment issue ... not the usual PART 1
« Reply #3 on: August 23, 2013, 02:26:23 PM »
The left fork has the fender under the caliper arm while the right fork has the the fender on the outside of the caliper arm... Is this correct? The fender looks like it's being pulled to the one side.

IW

Offline Ewan 500K1

  • Hot Shot
  • ***
  • Posts: 311
    • Adams Bros Probe 2001
Re: Dual Disc alignment issue ... not the usual PART 1
« Reply #4 on: August 23, 2013, 02:52:10 PM »
The left fork has the fender under the caliper arm while the right fork has the the fender on the outside of the caliper arm... Is this correct? The fender looks like it's being pulled to the one side.

IW

yep, thats correct as far as I know (happy to be corrected if I'm wrong though)  .. I think its assymetrical to allow the fixed brake line to fit between the muguard mounting bracket and the fork leg on the left hand side. When the mudguard is mounted on the stay it lines up with the tyre / wheel just fine
« Last Edit: August 23, 2013, 02:57:38 PM by Ewan »
jings, crivens, help ma boab

500 four K1 cafe racer build thread at :
http://forums.sohc4.net/index.php?topic=100883.0

Offline Ewan 500K1

  • Hot Shot
  • ***
  • Posts: 311
    • Adams Bros Probe 2001
Re: Dual Disc alignment issue ... not the usual PART 1
« Reply #5 on: August 23, 2013, 02:59:47 PM »
anyone know what model the hub with the speedo drive "flats" is off ? .. ie the hub in the second picture in reply #2
jings, crivens, help ma boab

500 four K1 cafe racer build thread at :
http://forums.sohc4.net/index.php?topic=100883.0

Offline sander

  • Full Member
  • *
  • Posts: 74
Re: Dual Disc alignment issue ... not the usual PART 1
« Reply #6 on: August 23, 2013, 03:05:02 PM »
Is the new axle straight? It happened to me once with an old cbr1000f.

Offline Ewan 500K1

  • Hot Shot
  • ***
  • Posts: 311
    • Adams Bros Probe 2001
Re: Dual Disc alignment issue ... not the usual PART 1
« Reply #7 on: August 24, 2013, 05:42:57 AM »
Attached photo of original and modified speedo drive plate which was modified from one exactly the same as the original
jings, crivens, help ma boab

500 four K1 cafe racer build thread at :
http://forums.sohc4.net/index.php?topic=100883.0

Offline Ewan 500K1

  • Hot Shot
  • ***
  • Posts: 311
    • Adams Bros Probe 2001
Re: Dual Disc alignment issue ... not the usual PART 1
« Reply #8 on: August 24, 2013, 05:44:01 AM »
The new hub came from my basket case 500 four with frame number 2120447, though not sure if that will be the bike's original wheel. I've been out measuring and comparing the old and new hub. The new nub (with the speedo drive flats) is 9mm thinner than the old one .. as measured between the flat disc mounting surfaces (measurement D in attached diagram). Presumably that is what is throwing things out ... but ... as long as I get the calipers aligned correctly to the discs it wont matter a hoot (will it !!! ?? ).
jings, crivens, help ma boab

500 four K1 cafe racer build thread at :
http://forums.sohc4.net/index.php?topic=100883.0

Offline Ewan 500K1

  • Hot Shot
  • ***
  • Posts: 311
    • Adams Bros Probe 2001
Re: Dual Disc alignment issue ... not the usual PART 1
« Reply #9 on: August 25, 2013, 10:01:57 AM »
The left fork has the fender under the caliper arm while the right fork has the the fender on the outside of the caliper arm... Is this correct? The fender looks like it's being pulled to the one side.

IW
ha , had another look. The mudguard bracket is not the same as the original .. suspect its off a 750 ... which probably exagerates the offset look ... but mudguard still lines up fine with the tyre when its on. See photo. Also checked and double checked the position of the caliper arm bracket / mudguard bracket and left hand fork assemebly ... the mudguard bracket deffo goes on top of the spindle bracket ( photos on Clymer 350-550 manual page 145 and Haynes 400/550  manual page 48)
« Last Edit: August 25, 2013, 10:08:08 AM by Ewan »
jings, crivens, help ma boab

500 four K1 cafe racer build thread at :
http://forums.sohc4.net/index.php?topic=100883.0

Offline Ewan 500K1

  • Hot Shot
  • ***
  • Posts: 311
    • Adams Bros Probe 2001
Re: Dual Disc alignment issue ... not the usual PART 1
« Reply #10 on: August 25, 2013, 10:03:18 AM »
Is the new axle straight? It happened to me once with an old cbr1000f.
checked spindle... straight as a die  ;)
« Last Edit: August 25, 2013, 10:08:47 AM by Ewan »
jings, crivens, help ma boab

500 four K1 cafe racer build thread at :
http://forums.sohc4.net/index.php?topic=100883.0

Offline Ewan 500K1

  • Hot Shot
  • ***
  • Posts: 311
    • Adams Bros Probe 2001
Re: Dual Disc alignment issue ... not the usual PART 1
« Reply #11 on: August 25, 2013, 10:39:09 AM »
oki doki, we now think the alignment problem is certainly because the new hub is narrower (off a CB750K0/CB450K3 ??) As I had a hub with flats I thought I'd go this way rather than drilling holes in the hub and using rivets to attach the speedo drive plate to a standard 500 hub ... but I never realised that this hub I have is narrower than the standard 500 hub !
What I think I need to do to correct the issue is:
I rebuilt the new wheel with new spokes and rim on the 450K3/750K0 hub with the speedo drive flats on it and modified the speed drive plate to suit that hub, so I quite fancy seeing if I can finish the job using that hub, rather than rebuilding another wheel.

I think what I need to do is:
1. On the right hand side  ..  I need to change this set up so that the caliper arm moves outward a bit relative to the disc by aabout a couple of mm, possibly by:
a) moving the muguard stay so that it is on top of the caliper pivot arm top bracket instead of between the bracket and the fork leg
b) shaving a bit off the bottom flat on caliper arm pivot where it bolts to the fork .

2. On the left hand side   Move the caliper arm inwards by a few mm relative to the disc, either by
a) using shims between the caliper arm pivot mounts and the fork (as in the 3rd picture in the first post in this thread and the 1st and 2nd pictures in the reply #2 in this thread)  AND/OR ..
b) make up a ring spacer to go between the disc and the hub, to bring the disc out from the hub a bit

jings, crivens, help ma boab

500 four K1 cafe racer build thread at :
http://forums.sohc4.net/index.php?topic=100883.0

Offline crazypj

  • I'm brill, me
  • Old Timer
  • ******
  • Posts: 4,467
  • first 100,000 miles. 1977 CB550F
Re: Dual Disc alignment issue ... not the usual PART 1
« Reply #12 on: August 25, 2013, 12:39:19 PM »
I think it would be better to reduce spacer length, put left side where it's supposed to be and do everything on right side
What size tyres are you using? I fitted WM3 front rim and can't get inflated tyre into forks as it catches on lower pivot mounting bolts
I fake being smart pretty good
'you can take my word for it or argue until you find out I'm right'

Offline Ewan 500K1

  • Hot Shot
  • ***
  • Posts: 311
    • Adams Bros Probe 2001
Re: Dual Disc alignment issue ... not the usual PART 1
« Reply #13 on: August 25, 2013, 01:17:42 PM »
I think it would be better to reduce spacer length, put left side where it's supposed to be and do everything on right side
What size tyres are you using? I fitted WM3 front rim and can't get inflated tyre into forks as it catches on lower pivot mounting bolts
woops, sorry crazyp.. you'd already suggested that in my other thread. Yes that might work too ... but maybe some issues:

a) The spindle nut may not then screw fully up to meet the shortened spacer, so would need to tap the spindle to make the threa for the nut longer ?
b) 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 .. this would result in the forks flexing inwards slightly .. would this matter ?

 Tyre I'm using on the front is an Avon Roadrider 100/90 , but on a standard rim. It does catch the lower pivot bolts, but makes it through with a shove. Gets past no bother without catching at all when deflated
« Last Edit: August 26, 2013, 02:36:11 AM by Ewan »
jings, crivens, help ma boab

500 four K1 cafe racer build thread at :
http://forums.sohc4.net/index.php?topic=100883.0

Offline crazypj

  • I'm brill, me
  • Old Timer
  • ******
  • Posts: 4,467
  • first 100,000 miles. 1977 CB550F
Re: Dual Disc alignment issue ... not the usual PART 1
« Reply #14 on: August 25, 2013, 09:21:16 PM »
Pinching the forks would be a bad thing but it wont happen.
The right side of axle is parallel so slides in fork clamp
The nut also has  a section without threads so it will usually screw down at least 1/8" more than needed
 Could probably just get axle and spacer from later bike to match hub you have
I fake being smart pretty good
'you can take my word for it or argue until you find out I'm right'

Offline Ewan 500K1

  • Hot Shot
  • ***
  • Posts: 311
    • Adams Bros Probe 2001
Re: Dual Disc alignment issue ... SORTED AT LAST
« Reply #15 on: August 27, 2013, 10:09:53 AM »
Another day in the shed... a day of revelations.  What I found was that all three of my caliper mounting brackets have different numbers 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 pivot 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 .

Thanks to BryanJ, Odjob and CrazyP for holding my hand through it all
« Last Edit: August 27, 2013, 10:12:26 AM by Ewan »
jings, crivens, help ma boab

500 four K1 cafe racer build thread at :
http://forums.sohc4.net/index.php?topic=100883.0