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Discussion Starter · #1 ·
I have searched the Honda workshop manual, this site and the net for instruction on setting up theis brake, and have concluded that there is pecious little information available on this subject.

On the face of it, it seems a simple, intuitive procedure, however I am not getting anything like the stopping force that I would expect.

I am sure that there is a wealth of experience among the contributors regarding this set up procedure.

I had the drum skimmed it was a long time ago, (the bike has done very few miles since though due to being in pieces in my shed) and I cannot remember by how much. I have new brake shoes (aftrmarket).

During my search I came across a site (which unfortunately I did not bookmark) that gave a value to the effective braking efficiency of the Bomber brakes. This was a number of 131.

The calc for % efficiency uses the bike weight, plus rider weight in lbs and a 30% factor for normal riding (e.g. under 100mph) 40% over 100mph.
so we have using me as the rider 411+200 =611.
30% 611 =183.3
131/183.3x100 =71.5% of an optimum figure.

Am I expecting too much from these brakes according to the model they need to be a minimum of 25% more efficient or over 100mph they need to be 47% more powerful?

These are of course theoretical values and gone are the days when I will be riding a "ton".

I would value any comments or advise that you can offer.
Thanks in advance
Nigel
Southampton UK
 

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Sensei
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Nigel..... Your intuition is correct.....You need two things.....The shoes and liner must not be glazed (light application of sandpaper) and both shoes must be set with the linkage adjustment so they touch simultaneously.... Careful adjustment of the cable will allow you to lock-it-up with two fingers
 

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Discussion Starter · #3 ·
An update, with a little estimation it looks as though 0.5mm was skimmed from the drum liner. There is also a high spot af maybe 20 degrees of .12mm. I dont know how significant that would be.
Std spec shows 4.5mm for the liners (these are new and are 4.5mm).
The effective ratio of radius would therefore only reduce the liners to 4mm 2mm above the minimum of 2mm. There should be enough meat on them.

I have tried to set the shoes to touch at the same time and the best I have achieved is a good fork dip from app 15-20mph but not even close to lock up.

The lever adjustment seems ok according to the manual. There does not appear to be glasing on the drum and the pads are new. Have tried start- stop to bed them in. I am still unhappy with the result.

I cant do any proper road riding as it has to pass the MOT test to get it legal, and naturally the brakes are definately part of that test.

I do have another hub and drum, but I have not laced a wheel myself and annoyingly I have only recently had new rims put onto this wheel.
 

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when i bought my cl450 the front brakes were ridiculous, I came to find that the two shoes were not synchronized and the cable preload was inadequate.

I loosened the turn buckle between the shoes to get the rear shoe out of the way

I put about 3-5mm of adjustment into the front brake lever to allow a little adjustment either way after the rest of the setup was complete

I tightened the cable at the drum end while spinning the front tire till the front shoe just starts to drag

I tightened the tie rod till drag on the wheel roughly doubled

tighten all jam nuts

adjust the lever a little to remove any drag

if this does not work, take a real good look at your linings and make sure your drum has not been pulled egg shaped by a tight spoke.

vintage brake linings has a pretty help section and if you are desperate enough to spend the long money, I'll bet they can set you up right..
http://www.vintagebrake.com/tips.htm
 

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Discussion Starter · #5 ·
I have looked at the drum and measured it with a friends needle guage. There is a high spot on the drum but this is only about .12mm which runs about 30 degrees of arc.

What I have noticed is that the brake backing plate actually moves away from the drum when the brake is pulled hard on. It seems spongy although it clearly isn't a hydraulic system.

Have you seen this on any of your bikes?

There is run out on the rim and maybe this needs looking at, I will try and sort out this to
see if it affects the braking.
 

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Sensei
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The backing plate should be held in place by the properly torqued axle....sounds like yours is loose....There shouldn't be any "room" for it to move..... :? Steve
 

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don't forget to apply the brakes while tightening the axle
 

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Discussion Starter · #8 ·
Hi
Thanks for all the replies. The simple solution in the end was to replace the drum. Which meant relacing a rim, which was a first for me. I did get it chcked over by a professional to be safe though. It passed the MOT test so it worked.

The second bit of information I have discovered, is, that for the REAR brake shoes, the book says 5mm shoe lining. Its too big as I discovered when I tried to put the newley relined brake back into the wheel. It didnt fit. I wasnt impressed at the time, and may have issued forth with a couple of things like oh bother!!!!!, or wasnt that silly!!!!!!........................... :oops: I think 4-4.5mm is more satisfactory, especially after using emery cloth to remove surplus friction material, that I had unwittingly paid for. Ah such is life, hey ho.
 
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