Topic: RE: 1975 CB750 Rear brake shaft & spring

[chewbacca5000]

I should know how thing thing works, but for some reason I am having the hardest time getting this back together.

 I have searched and consulted the manuals to no avail.

For what ever reason I can't seem to get the return spring to work properly.

Any help would be appreciated. 

[Vinhead1957]

Line the dots on the pedal arm and it should give you an idea where it should sit in reference to he frame

[flybox1]

that is correct, but, unhook the spring from is spot there under your thumb, first.  it needs to be 'unloaded'
slide the brake pivot shaft into its hole, with the upright, pointing straight up.  its top should be in front of the swingarm....and position the tag end(small bend) of the spring in its place on the frame rail
Just before you slide the shaft all the way thru, compress the 'hook' which is pictured under your thumb, into position around the upright....
might be easier too, to get the rear brake arm on, with the cotter pin, while this is all off the bike...

[MCRider]

that is correct, but, unhook the spring from is spot there under your thumb, first.  it needs to be 'unloaded'
slide the brake pivot shaft into its hole, with the upright, pointing straight up. its top should be in front of the swingarm....and position the tag end(small bend) of the spring in its place
Just before you slide the shaft all the way thru, compress the 'hook' which is pictured under your thumb, into position around the upright....

Critical: in front of the swingarm. YOu can get it to work otherwise, but it won't be right.

[flybox1]

that is correct, but, unhook the spring from is spot there under your thumb, first.  it needs to be 'unloaded'
slide the brake pivot shaft into its hole, with the upright, pointing straight up. its top should be in front of the swingarm....and position the tag end(small bend) of the spring in its place
Just before you slide the shaft all the way thru, compress the 'hook' which is pictured under your thumb, into position around the upright....

Critical: in front of the swingarm. YOu can get it to work otherwise, but it won't be right.

HAHA...yeah...i wrestled with this one for a while, but worked it out. 

[grepper]

I found fighting the spring was the hardest part.  So I compressed the ends together in a vice, tied a peice of cord around the two ends keeping them together.   Put everything together, then cut the cord.

[flybox1]

that'd work too 
I got mine in place then used a paint stir stick to compress the hook end and set it in place.

[PeWe]

I had photos of my bike where I saw how it sat before removal and repainting the frame.
It's a good idea to take some photos before, while working and afterwards so check can be done about how it sat before and how I did it when getting doubts about forgotten stuff somewhere now not visible.

[ekpent]

When I fiddled with one of those last because a PO had put it on wrong I had to remove the rear shocks and fold the swingarm up all the way and had just barely enough room to install in correctly in front. Thought maybe I would have to remove it(swingarm). Make sure its correct on yours.

[edwardmorris]

I found fighting the spring was the hardest part.  So I compressed the ends together in a vice, tied a peice of cord around the two ends keeping them together.   Put everything together, then cut the cord.

Clever! Saved note for assembly time, thanks!

[chewbacca5000]

Ok I see what you guys mean about having the shaft in front of the swing arm.  Now can I install with the rod in place or not?

In the future this will be one of the first things I do and not the last.

[MCRider]

Ok I see what you guys mean about having the shaft in front of the swing arm.  Now can I install with the rod in place or not?

In the future this will be one of the first things I do and not the last.

Yeah I forget the exact sequence but there is a good way and a bad way to do it.  I think it can be done with the rod in place but probably not part of the good way.

[chewbacca5000]

Ok I got the shaft and spring back on using flat head screwdriver.  Shaft is in front of the swing arm.  Found out the curved part of the shaft bracket needs to be facing down.


Going to the auto store to get carter pin.  Cheapo from HF is too flimsy.

To anyone doing a frame off I would recommend making this one of the first steps.  Much easier without all the oil hoses and spring arm, etc.. in the way.

Should be ok from here.  Thanks for all the help guys!

[madmtnmotors]

Found out the curved part of the shaft bracket needs to be facing down.

This is wrong, or else I don't understand your description. The inner part (flanged) piece should be up.

[chewbacca5000]

Found out the curved part of the shaft bracket needs to be facing down.

This is wrong, or else I don't understand your description. The inner part (flanged) piece should be up.

You might be right about that.  I now I had the brake rod on the wrong way at first and had to switch it.

[madmtnmotors]

When facing the side of the bike, standing on the right, looking at the brake pedal:

>The rear brake pedal pushes down, which creates a clockwise rotation of the shaft to actuate the brake.
>To activate the rear brake requires a "pull" on the lever at the rear drum.
>If the forward shaft (at the pedal) had the flange down, then the clockwise rotation of the shaft would generate a "push" against the lever at the rear drum.
>With the flange at the forward shaft (at the pedal) in the up position the clockwise rotation of the pedal shaft will exert the correct "pull" action on the linkage shaft.

I, too, have done it both ways, only one works though. 

[jebon]

Hi!
I found this thread because I'm having a bit of trouble with my rear brake. Hope someone's still watching.

I can kind of get my rear brake to work, but only with the pedal at this point on the shaft. Is this correct? The flange is facing up so it pulls, but I need to have the rear bolt and spring really tight, like bottomed out for it to brake. If I put the pedal in the next notch counter clockwise, then the flange hits the engine case. Pedal one notch clockwise and it hits the exhaust. I can't really figure out what's wrong.

PO had the bike apart and a lot of other stuff was wrong

[jebon]

I should know how thing thing works, but for some reason I am having the hardest time getting this back together.

 I have searched and consulted the manuals to no avail.

For what ever reason I can't seem to get the return spring to work properly.

Any help would be appreciated.

Does the flange come off the shaft?
Because I think mine faces forward.

[madmtnmotors]

Hi!
I found this thread because I'm having a bit of trouble with my rear brake. Hope someone's still watching.

I can kind of get my rear brake to work, but only with the pedal at this point on the shaft. Is this correct? The flange is facing up so it pulls, but I need to have the rear bolt and spring really tight, like bottomed out for it to brake. If I put the pedal in the next notch counter clockwise, then the flange hits the engine case. Pedal one notch clockwise and it hits the exhaust. I can't really figure out what's wrong.

PO had the bike apart and a lot of other stuff was wrong

Post a picture of the brake arm at the rear hub as well. The brake arm on the rear hub can be removed and rotated on its splined shaft. There may be index marks on both the rear brake arm and the splined shaft that it fits on.

[jebon]

Hi!
I found this thread because I'm having a bit of trouble with my rear brake. Hope someone's still watching.

I can kind of get my rear brake to work, but only with the pedal at this point on the shaft. Is this correct? The flange is facing up so it pulls, but I need to have the rear bolt and spring really tight, like bottomed out for it to brake. If I put the pedal in the next notch counter clockwise, then the flange hits the engine case. Pedal one notch clockwise and it hits the exhaust. I can't really figure out what's wrong.

PO had the bike apart and a lot of other stuff was wrong

Post a picture of the brake arm at the rear hub as well. The brake arm on the rear hub can be removed and rotated on its splined shaft. There may be index marks on both the rear brake arm and the splined shaft that it fits on.

Do you mean the retainer shaft (don't know what it's called. This is very close to the wheel btw) or the rod with the adjuster. I took this picture earlier to show how much I need to tighten to get the pads just to touch. Wondering if the pads are worn all the way down but I think that's unlikely.

[jebon]

And if I take the pedal one notch counter clockwise, then I only have this much leverage before the flange hits the engine case.

[RAFster122s]

The arm for the cam where your adjustment nut. The cam for the brake backing plate has a dot on it. The arm that attaches to that splined shaft also has an alignment mark. If it were assembled wrong it could be that you have to have it excessively adjusted...
Photograph that arm and the brake backing plate so we can see these marks before you pull your rear wheel to investigate further..

[RAFster122s]

That is hitting your exhaust shield or exhaust, not the case.
What exhaust is on the bike? It is a K bike right and not an F?

[madmtnmotors]

The rear brake arm can be removed from it's splined shaft at the brake hub, and then reinstalled rotated further towards the rear. Look for a dot on the splined shaft and a dot on the rear brake arm.

[jebon]

That is hitting your exhaust shield or exhaust, not the case.
What exhaust is on the bike? It is a K bike right and not an F?

It's the flange hitting the case for sure. I've been back and forth between two notches about ten times. If I move it one clockwise, then it's able to hit the exhaust but then i can't pull enough to brake. If the rod is threaded into the hinge then it should be screed further into the hinge. Haven't tried that