[MadDogMcQ]

Contrary to all the period test-reports, the front brakes on my CB450 are not very good!

I've ordered a new set of brake shoes from CMSNL.com and will be stripping down the front wheel when they arrive, so is there anything I should know that is peculiar to the CB450?

One thing I note (which seem strange to me) is that the operating lever isn't a true 90 degrees to the cable. Looking around at other 450's and in the manuals, this seems to be correct, but everything in my head tells me that it would be more efficient if it were at 90.

 

[66Sprint]

Contrary to your brain, the angle relative to the cable stay point has no bearing on how well the brakes function.... The arm will travel through an arc, (the same arc), regardless of its starting position before the brakes apply.... Reducing the arc (having the shoes internally closer to application/touching) and adjusting so BOTH shoes apply simultaneously WILL make them more effective....Deglazing both the drum and the shoes and the adjustment are the keys to making it work....

 

[fasterspider]

That is why they switched to disc brakes, experience dictated and the designers listened.
The drum brakes on my 350 leave a lot to be desired but, they are sufficient when riding the bike like a normal human being.
I can do stoppies on my Blackbird and even on my CBX but, my Scrambler needs to be braked with respect.

 

[MadDogMcQ]

Contrary to your brain, the angle relative to the cable stay point has no bearing on how well the brakes function

That hurts my small brain :lol: As I see it.....

 

[tbpmusic]

I should preface this by stating that I don't have a drum brake here to look at......
All the photos and drawings I see indicate that the "geometry" of you lever system is ok.
Like Steve suggested, a good cleaning, sanding, and particularly adjustment should improve your stopping power considerably.

My memory may be at fault, but don't those lever shafts on the drum have splines that only allow the lever to go on in one position??

 

[Bird76Mojo]

The levers can go onto the shafts in any position, just like your shifter. If the angle was as great as his little "man" drawing then it would be extremely inefficient for the system but from his actual brake picture the angles are nowhere near that great. It should function just fine the way it is.

AFTER following Steves suggestions...


GB :mrgreen:

 

[66Sprint]

Mad Dog.... The shoes don't actually "grab" during the first several degrees of "arm" movement...But, IF they started with the arm at 90 degrees, they would become "less efficient" (your terminology) as the arm moved further towards the "pull" (anchor point)... The way they are set-up, they apply a progressively firmer (more leverage advantage) "bite" and transmit better "feel" to the rider.....

OH...GB... They ARE "keyed" to limit the amount of possible adjustment to one spline or so..... They will NOT go on in just any position.......

 

[MadDogMcQ]

Okay, I'll believe you

Hopefully, I'll get them working well when I get around to doing the job.

Tom

 

[66Sprint]

Mad Dog... From the posted pic, the fork axle cap on the left leg is (looks to be) on backwards.... The "taller" end goes forward, and should be tightened first.... There should be a small "pinch gap" at the rear..... IF you put them on backwards, and tighten the front nut first, they do not adequately pinch and retain the axle.....

 

[ihatespeed]

+1 on Steve's suggestions. just be aware it has period brakes and you will be fine.

 

[tbpmusic]

Actually, early 450 disks aren't all that much better than a good-working drum of the K2 era.
At least I never thought so.

You just need to get it set up right.

 

[Bird76Mojo]

Sorry for posting the wrong information guys. The last drum assembly I took apart out back wasn't keyed that way from what I remember seeing. I was thinking of scavenging some parts when I took it apart.. I coulda sworn... :lol:

Although it was from a 350 I think..? I'm sure there's no real major differences though..


GB :mrgreen:

 

[otr002]

One thing that i have found over the years is that some people adjust the brakes just by using the connecting rod only, all this achieves is that one shoe makes contact before the other giving reduced braking.
You need to adjust the connector between the two Brake Cam Levers (arms) so that both ends of each shoe contacts the brake drum at the same time.

To do this, loosen both the cable adjuster and the rod connecting the two brake cam levers. Tighten the cable adjuster. The one on the brake drum, not the one on the handlebar. When the brake starts to drag, keep turning the wheel and get a good " feel " of how much drag there is. Now tighten the rod going to the other brake cam lever till the drag " feels " about twice as much as before. Tighten the lock nut, then adjust the cable so that there is at least an 1/8" of play at the handlebar brake lever.

By adjusting the play you can make the brake lever engage the brake wherever you like. Like closer to the handlebar if you like. Just make sure there is enough free play in the cable so the brakes don't drag, and that the lever does not touch the handlebar when they are on full panic :shock:

How do you tell if they are dragging ? Feel the drum after a short ride. If it is really hot and you have not used the brakes much, they are dragging. If you are sure the brakes are not dragging and the drum is still hot, check your wheel bearings.

Edit:- Genuine Honda pads are made using 1960-70s technology so before spending $ have a look for a relining service that uses modern friction material AND has a history of relining motorcycle drum brakes and get the friction material that suits your riding style, the cost should be similar or slightly more expensive.

Personal option :shock: You should never compromise on brakes and tires as these are the two greatest factors on a motorbike that will save your life

Edit number 2:- Another trick/mod you can do is shaving the leading edge of the shoes in 1/2" steps so that the shoes initially make contact in smaller increments giving you the ability to use the brake to softly slow you speed in a situation where you would normally not use the brake, I'll leave it their, let you think about, and wait for the responses

Edit number 3:-

 

[otr002]

Quick web search found these two But do a local search as you should be able to achieve the same result with less $.

http://www.saftek.co.uk/vintage/saftekservices.html

http://www.vintagebrake.com/drum.htm

 

[66Sprint]

I agree with Rod... Synchronizing so both shoes apply simultaneously and to the same extent is critical....And modern compounds are way more efficient.....

 

[MadDogMcQ]

I'll check that out 66 - thanks.

Thanks for that info Rod - your time is appreciated. I have already ordered genuine replacements from CMSNL.com and am waiting for them to arrive. ZZzzzzzz

 

[MadDogMcQ]

.

 

[Bird76Mojo]

Look like Vesrah shoes to me. I see the name there. That crack is no good. I'd be looking for a replacement..

GB :mrgreen:

 

[tbpmusic]

MAc -

GB is right, you need to find a new wheel, and quick too.

 

[MadDogMcQ]

CMSNL.com have no damned new shoes in stock!