Rear Drum Brake Assembly

D

Dale

Senior member
Location
Malta
Would anyone out there have some photo's of the assembly of a rear drum brake ('74 SF2, but I think it is the same as a drum brake on an early triple)?
Having decided to return from cast to wire wheels, and not being able to afford a wire/disc rear setup, I have pulled out the old Boriani's, and now cannot remember the details of the assembly.

I have the green book, and have looked at the diagram on Laverda Paradise, but have one problem that I cannot figure out without help:
There is a large sleeve that sits against the bearing on the drum, through the conical cooling plate and the sprocket plate bearings, and has a washer and nut on the outside (swing arm side).

Having fitted it in, I find that it extends about an inch past the sprocket plate.  Is this correct, or should there be a spacer?
I find it strange that, if correct, the bolt and washer will sit against the inside of the swing arm, and nothing will stop the sprocket carrier from sliding out.

Thanks.
Dale
 
Hi dale -there is a spacer between the sprocket carrier and swinger - - the large nut that goes over the large sleeve retains the spkt carrier and works well to make it a QD rear wheel. I presume you have re-fitted the drum type swinger as it has a larger slot for the sleeve that side - Regards - Phil
 
Thanks for that Phil.
It is not obvious from the diagrams.

Am planning to fit the original swing arm as you suggest.

A couple of questions:
How big should the spacer be?
What is a QD wheel?  (Probably a silly question).

Dale
 
What is a QD wheel?  (Probably a silly question).



A nice piece of classic bike technology, chain and sprocket with carrier stay put when you take wheel out, from the opposite side of course.
Paul
 
So...
I've had another go at it, and still cant make it look right.

Is there no-one with a photo of the completed sprocket carrier set-up for me?

Dale
 
hi Dale - Spacer looks to be about 4mm - I found my bike was running 1mm out on chain alignment when std so may have "adjusted" it - Photo may help - regards - Phil
 

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Thanks fellows.

Got it now.
I was trying to fit the spacer nut inside the swing arm rather than outside as Phil's photo shows.

I apreciate the help.
Dale
 
phil37 said:
hi Dale - Spacer looks to be about 4mm - I found my bike was running 1mm out on chain alignment when std so may have "adjusted" it - Photo may help - regards - Phil
Click to expand...

Hi Phil. What's the quick & easy way to check chainline? Ideally it'd be relative to the gearbox sprocket, but stringlining to that is ... difficult.
Quentin
 
I use a straight-edge, but sometimes it's a pain in the arse if there's stuff in the way - like the bike frame. There are various laser alignment tools that are available pretty cheaply now that would make the job pretty easy.
 
Hi Phil. What's the quick & easy way to check chainline? Ideally it'd be relative to the gearbox sprocket, but stringlining to that is ... difficult. 
Click to expand...

Hi Quentin - yes a long straight edge that will not flex and clear the frame isn't so easy. I used  2 separate 13 inch lengths of 10mm keyway steel (perfectly straight  and square  - plus I had some laying around) - one clamped to the  rear sprocket and the other clamped to the g/box sprocket - easy to see any misalignment then. - regards - Phil
 
Nice one, Phil. I'll go with that.

On bicycles, we measure chainline Fr & Rr from the frame & wheel centre points - I guess it would be possible to find the effective centre of the cases and the Rr wheel, then go from there, but there is probably too much room for vagiaries to enter the process (like the motor being a mil off centre due to imperfect engine mounts or swingarm not dead centre relative to engine/frame). Your sys lines up the important bits. I reckon mine's definitely off, as chain wear seemed excessive (when last used) - and it wasn't the quality of the chain.
q
 
You'd like to think if the sprockets were in line with each other then the wheels would be too - otherwise something must be very odd somewhere! But yes, string-lining the wheels would be a decent start. or maybe align the sprockets and then check wheels!??!
 
laverdakeith said:
I start with the wheel alignment then adjust the chain run if necessary afterwards, good to have the wheels dead in line.


  Keith
Click to expand...

Hey Keith,
Good and obvious advice.. just curious though, if the wheels are aligned and then the sprockets are found to be out of alignment, how do you then realign the sprockets? spacers or shims somewhere? How much non-alignment can be tolerated? I'll be doing all this presently as I need to replace all the wheel bearings on the Mirage  :-X I suppose I should look in the Green book..
 
On a standard set up everything should be about right if not move it in a bit or move it out a bit, a chain will tolerate a little mis alignment but obviously best to have everything dead in line for smoothness and longevity. What was up with the wheel bearings, please don't say no spencers fitted..... ;)


  Keith
 
laverdakeith said:
On a standard set up everything should be about right if not move it in a bit or move it out a bit, a chain will tolerate a little mis alignment but obviously best to have everything dead in line for smoothness and longevity. What was up with the wheel bearings, please don't say no spencers fitted..... ;)


  Keith
Click to expand...

I won't say that.. :-X :-X  :o  let's just say the preparation and fitment following powder coating could have been better. Better yet if they'd been renewed.. :-X
 
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