4LS Front Brake

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olChris

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I acquired this 4Ls Brake (750 suzi) as part of my recent basket purchase.. Into my trial fitting of parts i have found the brake drum assembly is 15mm toooo wide for the front forks.. I believe this was a fairly common mod years ago.. I was "assured" that it was ready to "just" bolt in. (and haven't you heard that before..) Any tips or recollections would be helpfull.. It appears that the hub has been retro fitted to accept Norton axle and some machining has taken place on both sides of the hub. This is particularly evident on last photo where it can be seen the speedo drive housing has been slightly skimmed

4LS Front Brake


4LS Front Brake


4LS Front Brake


.
 
We see you have met our resident lurker/troll.
How would he know - doesn't own a Commando.... !
 
I dont know about fitting one of those on a Commando however I recently met an elderly gentleman with one fitted to his much modified Vincent Racer, an old Westwood raceway bike. It looked great on there but he informed me it was "completely useless in the rain". I thought it might be good to know before you go to a lot of work. Perhaps someone here with the same brake has a different experience and can comment.

Glen
 
A lot of drums are not too good in lots of water though.
Plenty of disks too.
Thats why the owners manual warns you to dry out the brakes after riding through a creek, etc.
Riding in heavy rain isn't much different. ?

Something I drove through a deep puddle a while back took nearly 300 yards to dry the brakes out afterwards,
when I took particular note of how much drying they took.
So don't expect to stop suddenly if they haven't been dried out...
 
He put the brake on in order to go road racing. It worked well in the dry but was very inferior to the stock brake in rain.

Glen
 
:D :D :D I cant be to sarcastic cos that enables your thread to crash and burn.....

I have this brake drum and all its associated mechanicals which is good but only 70% of the rear hub (Norton) in my new basket case, no rims no spokes no master c's ... If this 4LS brake is going to be "difficult", i'm toying with the idea to fit late model rim/brakes/tyres and associated parts from one make (Jap or whatever) to modernize braking(disks) cylinders masters being all same make/breed.. As we all know spending $2k on rims/tyres/brakes/ M/C's etc is real easy to do. Especially when, mixing and matching one off custom parts.. $2k will buy a lot from the wreckers here !!! if i now what to look for........ Any ideas or suggestion down that track??
 
Have a look at Ludwigs 300 lb Commando thread, he got rid of a lot of weight by switching the wheels out. Also much improved braking. Some fitting required tho.

Glen
 
Depends on how close to original you want to keep it ?

Someone will have fitted that Suzook front brake.
Wait until you hear how they did it ??
Machining away the fork legs may well come into it.
(Not all changes are always 'improvements' ?).
The brake pad material probably determines the wet performance.

Is the stock 2LS Norton front brake out of the question ?
Nortons sell quite well in stock form, and well set up, that brake is reasonable ?
So well worth spending the cash on.

Ditta the rear wheel/ brake - which it seems the discussion has moved on to.
Madass on this forum is doing a version of improved rear wheel with cush drive, probably at his usual bargain prices...

Unles you have plans to upgrade the whole thing ....
 
olChris said:
:D :D :D I cant be to sarcastic cos that enables your thread to crash and burn.....

I have this brake drum and all its associated mechanicals which is good but only 70% of the rear hub (Norton) in my new basket case, no rims no spokes no master c's ... If this 4LS brake is going to be "difficult", i'm toying with the idea to fit late model rim/brakes/tyres and associated parts from one make (Jap or whatever) to modernize braking(disks) cylinders masters being all same make/breed.. As we all know spending $2k on rims/tyres/brakes/ M/C's etc is real easy to do. Especially when, mixing and matching one off custom parts.. $2k will buy a lot from the wreckers here !!! if i now what to look for........ Any ideas or suggestion down that track??
Click to expand...

I have no experience of the Suzuki brake, but a little with other 4ls (and 8ls) brakes. In my experience Chris, a good and well set up 4ls front brake is better than a stock Norton disc by quite some margin. But, and its a big but, it must be re-lined by someone who really knows what they are doing in order to use the correct lining material and ensure the correct thickness. When the thickness is correct, a 4ls brake creates a kind of self servo effect and makes for a great brake.
The correct material will also be better in the wet than stuff of old. Duct tape over the air scoop intake in really bad weather also helps!
The trouble with a drum is that you have to put (a lot of) effort into ensuring all this is done correctly, and ensuring it stays adjusted correctly, whereas a good disc set up is 'fit and forget' apart from checking the pads once in a while.
So... If you're a drum brake fan, they can be made to work.
But... If you simply want a good brake, a disc set up may suit you better. Also, near in mind that you will get good money for the Suzuki brake on eBay, cafe racer builders love 'em!
 
Older 70s or 80s BMW front ends have Brembo twin discs set ups but spoke wheels an so look the part. I have seen one or two fitted to a few Triumphs an Nortons in magazines in the past. But the donor bikes are now classic them selves so parts will be pricey now just like Norton bits. Plus the breakers would I imagine be full of newer Japanese bikes in which case anything will fit any bike with enough time and effort but it its easy to spoil the bike with mixing modern parts like upsidedown forks an old style air cooled twin engine. You could end up with something that is nether classic nor modern and may not even ride well if rake trail and spring an damper rates etc. arnt right.
Fitting none standard parts is easy but be careful as getting them to work as you want can be much hard.
 
The early ATEdisc brakes on airheads are fairly crap in stock form, but the cure is the same as with the Norton front brake, sleeve down the mastercylinder to get a more powerful progressive brake with some feel. Obviously in the 70s the guys who specked the early disc brakes were too conservative, probably worried that the owners would keep locking up the front wheel.

The Brembos from 82 onwards are much better, but finding them fitted to a spoked front wheel is difficult, as spoked front wheels were only found in UK specced police bikes
 
As a "Rule of Thumb" i use the philosophy of, bolt it on and then unbolt it off. As this package has matching numbers and i couldn't bear the horror's restoring to concours condition (with newly reproduce part' ????? ) I will leave that for the next owner. In the meantime i will maintain the integrity of the 3 matching numbers and not weld, machine nor modify any of the original components and get it on the road albeit with disc brakes from a honda, suzi, trumpy and Corbin seat.. Bolt on, Bolt of.. Still having 3 matching numbers is a remarkable thing after 40 yrs !!! It would be interesting to do a poll on the members here..
 
milling machice? a bit of the drum and a bit off the sliders..thats easy ..torque stays ...a bit more fiddling..remember the stays need to be at the correct angle,otherwise the stays tend to bend on braking.
 
Earlier drum brake Commando yokes have 7 inch hole centers and later yokes have 7 3/8 inch hole centers. From your photos I guess you have a set of forks an yokes so you may be be lucky to find a wheel that will fit. I would not thin the axle mount in the sliders as the pinch bolt side is well known to brake if over tightened as it is.
ebay is always worth a look there seem a steady supply of wheels etc. it may be far easier to use standard parts an up grade parts come up to as people return bikes to stock.
 
olChris said:
I acquired this 4Ls Brake (750 suzi) as part of my recent basket purchase.. Into my trial fitting of parts i have found the brake drum assembly is 15mm toooo wide for the front forks.. I believe this was a fairly common mod years ago.. I was "assured" that it was ready to "just" bolt in. (and haven't you heard that before..) Any tips or recollections would be helpfull.. It appears that the hub has been retro fitted to accept Norton axle and some machining has taken place on both sides of the hub. This is particularly evident on last photo where it can be seen the speedo drive housing has been slightly skimmed

4LS Front Brake


4LS Front Brake


4LS Front Brake


.
Click to expand...
i have one of these brakes fitted on my BSA A10 they are a very good brake you need a good balance bar and route the cables carefully and take time to set the brakes up properly ,i met someone last year with a norton lowboy that had this type 4ls fitted but i cant remember what yokes he had regards baz
 
I have a GT750 brake setup around here that we used to run on a Norton we ran in WERA V3. I probably couldn't find it in any timely fashion due to an industrial sized move recently. If i do, I will do the photo thing.

One thing I do remember was that one braking plate assembly lost the center bushing when it was milled to clear the centering bosses of the Roadholder bottoms. we had to counter-bore the backing plate and install a shouldered bushing. Not a NASA level engineering project, but. One solution would have been to trim the folk bottoms.

Looks like your backing plates have already been cut. I would encourage you to ensure that there is enough contact between the steel bush and the cast aluminum housing .

Rj
 
I seem to remember machining the backing plate of a T500 drum brake to make it fit. I was never happy with it. The Japanese seem to do a lot of value analysis and they never leave much excess material on any component.
 
Could you not sell that brake an put the cash raised into another brake option??
After all that brake is from what is now a classic Japanese bike.
 
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