Author Topic: Lets build a SOHC for less than a grand  (Read 24575 times)

Offline Spitfire

  • SOHC Master
  • Posts: 1769
    • View Profile
Re: Lets build a SOHC for less than a grand
« Reply #135 on: January 20, 2020, 10:46:58 AM »
It's great watching somebody that knows what they are doing, and as Paul said a great guide for someone doing the same job.

Cheers

Dennis
1976 CB750F

1977 CB750F2 In bits

1964 BSA A65R In bits

Offline Erny

  • CB750K7 CB550K1
  • SOHC Pro
  • Posts: 522
    • View Profile
Re: Lets build a SOHC for less than a grand
« Reply #136 on: January 20, 2020, 10:52:06 AM »
Graham,

thanks for detailed step by step description, will follow if I'll be doing rebuild one day
CB750K7 US model (1977)
CB550K1 US model (1975)

Offline Trigger

  • Grogu
  • *
  • Posts: 8434
  • Engines built on reputation, not advertising.
    • View Profile
Re: Lets build a SOHC for less than a grand
« Reply #137 on: January 25, 2020, 02:14:17 PM »
Bucket back from the zinc platers so, got the wheels back together and the first problem was the brake shoes. Some folk recon they don't have a problem fitting the 550 ones to the 500 four as, Mr Webley did and I have taken this up with DSS and EBC so many times now and all I get is " well the computer says it is a match".
The late 550 is 20.68mm at the pivot point and the 500 is only 20.00mm, this makes a big difference when trying to get the split pins in and other fitting problems.
I found a good Honda secondhand set, that has enough meat on and will send a old set away to have new shoes fitted.

[ Guests cannot view attachments ]


[ Guests cannot view attachments ]


[ Guests cannot view attachments ]
« Last Edit: January 26, 2020, 11:48:45 PM by Trigger »

Offline Trigger

  • Grogu
  • *
  • Posts: 8434
  • Engines built on reputation, not advertising.
    • View Profile
Re: Lets build a SOHC for less than a grand
« Reply #138 on: January 25, 2020, 02:23:14 PM »
Wheels on and the bike is stable enough to fit the engine.
As I have already chased all the threads, just a quick squirt of silicone oil on the head studs and put in with my fingers.
Last thread turned with a torque wrench  ;)



  [ Guests cannot view attachments ]


[ Guests cannot view attachments ]
« Last Edit: January 25, 2020, 02:25:46 PM by Trigger »

Offline Bryanj

  • Grogu
  • *
  • Posts: 10694
    • View Profile
Re: Lets build a SOHC for less than a grand
« Reply #139 on: January 25, 2020, 04:05:32 PM »
Graham, do you know if the 450/500 twin shoes are different?

Offline Trigger

  • Grogu
  • *
  • Posts: 8434
  • Engines built on reputation, not advertising.
    • View Profile
Re: Lets build a SOHC for less than a grand
« Reply #140 on: January 25, 2020, 07:01:29 PM »
Graham, do you know if the 450/500 twin shoes are different?

They were the same part number yonks ago before they started superseding all the part numbers. There used to be loads of people that used to re shoe brakes. You can still get them done for around £15 for the pair  ;)

Offline Trigger

  • Grogu
  • *
  • Posts: 8434
  • Engines built on reputation, not advertising.
    • View Profile
Re: Lets build a SOHC for less than a grand
« Reply #141 on: January 26, 2020, 10:31:42 AM »
Back tracking to these brake shoes : Had a dig about and found two OEM sets. ASK-1037SR2 are the 390 type and ASK-A7GG are the 323 type. Two different manufacture part numbers  ;)

Offline Trigger

  • Grogu
  • *
  • Posts: 8434
  • Engines built on reputation, not advertising.
    • View Profile
Re: Lets build a SOHC for less than a grand
« Reply #142 on: January 26, 2020, 11:37:40 PM »
Spent a few hours today trying to get the calipers to sit flat to the disc. A little hard as I have a tiny lip on the disc and after all my efforts I still had the right caliper toeing out by 0.65 top and 0.70 at the bottom. Had a measure up of the left caliper and that was not sitting flat to the disc.
I am not sure now how flat these should sit to the disc.



[ Guests cannot view attachments ]


« Last Edit: January 26, 2020, 11:39:15 PM by Trigger »

Offline Bryanj

  • Grogu
  • *
  • Posts: 10694
    • View Profile
Re: Lets build a SOHC for less than a grand
« Reply #143 on: January 27, 2020, 09:41:24 AM »
Dont ever remember checking that Graham, as its a swinging caliper the pads wear at an angle(of sorts) anyway.

Offline Trigger

  • Grogu
  • *
  • Posts: 8434
  • Engines built on reputation, not advertising.
    • View Profile
Re: Lets build a SOHC for less than a grand
« Reply #144 on: January 27, 2020, 09:52:03 AM »
Dont ever remember checking that Graham, as its a swinging caliper the pads wear at an angle(of sorts) anyway.

The left is the standard factory set so, the right has to be a mirror image. I need half a mm at the rear of the caliper ( closest to the fork) as with the disc spinning the pad will digs in on the right side at the moment with the measurements shown. If that makes sense ?

Offline Erny

  • CB750K7 CB550K1
  • SOHC Pro
  • Posts: 522
    • View Profile
Re: Lets build a SOHC for less than a grand
« Reply #145 on: January 27, 2020, 09:59:41 AM »
Graham, isn't this somehow automatically "solved" once new pads are worn enough (first 100-150 miles)?


Odoslané z SM-G930F pomocou Tapatalku

CB750K7 US model (1977)
CB550K1 US model (1975)

Offline Trigger

  • Grogu
  • *
  • Posts: 8434
  • Engines built on reputation, not advertising.
    • View Profile
Re: Lets build a SOHC for less than a grand
« Reply #146 on: January 27, 2020, 12:26:05 PM »
It is hard to explain without getting too technical .
The first thing is why all these sites on a double disc are advising you pack the top pivot arm out with washers?. I have tried this and the caliper is not parallel to the disc.
The second concern is the left factory one has 0.50mm gap nearest the fork and sits flush at the front of the caliper touching the disc . I find this correct as when the disc is spinning the brake pad touches the disc at the front and it will drag to bed in.
The right hand caliper is touching at the back ( nearest the fork leg) and has a gap at the front. If you put a cylinder of metal in a lathe and spin it anti clockwise you can use a cutting tool if it is straight, angle the tool down and it will drag and still cut but, if you angle the tool up to cut in to a cylinder, that tool will start to judder and may snag and break.

So....what I am finding is that I need to skim a little bit of metal off of the caliper mount on the fork or, shave some metal off of the pivot arm mounts  :-\ :-\ :-\ Which on all these web sites, no one has advised to do.

Offline Oggie400F

  • SOHC Member
  • Posts: 192
    • View Profile
Re: Lets build a SOHC for less than a grand
« Reply #147 on: January 27, 2020, 12:29:44 PM »
Spent a few hours today trying to get the calipers to sit flat to the disc. A little hard as I have a tiny lip on the disc and after all my efforts I still had the right caliper toeing out by 0.65 top and 0.70 at the bottom. Had a measure up of the left caliper and that was not sitting flat to the disc.
I am not sure now how flat these should sit to the disc.

(Attachment Link)

Interesting discovery on the measurements for the left Caliper.
I’m going to check mine to see what they are like. I’m still waiting on parts for the twin disc upgrade on my bike and am watching yours with interest.
Great info Trigger. This is really going to help me.
Just one thing I’ve noticed is that the Caliper adjusting pin extends beyond the fork attachment lug on the picture. Is this standard length or extended as I note that the locking nut is fitted inside to enable the spring to be compressed adequately?
I'm a Radiographer............I can see right through you!!

1999 VFR800 fix in Pearl Prism Black
1978 CB750F1 in Candy Presto Red
1976 CB550F Supersport Brat Bike in Black
1976 CB400F in Varnish Blue - project bike in many bits.

Offline Erny

  • CB750K7 CB550K1
  • SOHC Pro
  • Posts: 522
    • View Profile
Re: Lets build a SOHC for less than a grand
« Reply #148 on: January 27, 2020, 12:30:49 PM »
OK, now I see!
I did not "read" your drawing properly...
Just thinking, maybe this issue does not exist on CB750 dual disk setup?
CB750K7 US model (1977)
CB550K1 US model (1975)

Offline Trigger

  • Grogu
  • *
  • Posts: 8434
  • Engines built on reputation, not advertising.
    • View Profile
Re: Lets build a SOHC for less than a grand
« Reply #149 on: January 27, 2020, 12:42:41 PM »
Spent a few hours today trying to get the calipers to sit flat to the disc. A little hard as I have a tiny lip on the disc and after all my efforts I still had the right caliper toeing out by 0.65 top and 0.70 at the bottom. Had a measure up of the left caliper and that was not sitting flat to the disc.
I am not sure now how flat these should sit to the disc.

(Attachment Link)

Interesting discovery on the measurements for the left Caliper.
I’m going to check mine to see what they are like. I’m still waiting on parts for the twin disc upgrade on my bike and am watching yours with interest.
Great info Trigger. This is really going to help me.
Just one thing I’ve noticed is that the Caliper adjusting pin extends beyond the fork attachment lug on the picture. Is this standard length or extended as I note that the locking nut is fitted inside to enable the spring to be compressed adequately?

I just put the nut next to the spring to pack it out while I waited for a longer spring to arrive, 45mm long at the correct spec. As this is not a original build, I just use a countersunk M6 machine screw as adjustment screws.


[ Guests cannot view attachments ]


[ Guests cannot view attachments ]



 

SimplePortal 2.3.5 © 2008-2012, SimplePortal