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LI special - swansong project?

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Re: LI special - swansong project?

Postby jonw » Tue Feb 23, 2021 12:32 pm

dickie wrote:
jonw wrote:Are you using the capacitor to supply ancillaries?

Yes, and no. I run full DC system and the capacitor is just there as a smoothing load for the entire system as I don't use a battery. I don't need a battery so it would just be something to maintain.

What I mean by full DC is that lighting and ignition are fed by the same 12V DC supply, like in a car.

Sorry if I've patronised you, but most lambretta folk don't know what I mean by full DC.


Not patronising at all Dickie as I don't have a clue about electrics!
I use a Varitronic ignition which has a "battery" lead and I would really like to power some heated gloves and so thought a capacitor may be a solution over a battery?

Sorry to get off topic.
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Re: LI special - swansong project?

Postby dickie » Tue Feb 23, 2021 1:15 pm

You need to know what power the gloves are and how much power the varitronic dc supply can provide. A battery would help, but only until it goes flat. Which I I wouldn't have thought would be very long at all. A quick look at gloves show them around 25watts. A capacitor won't help you at all. A battery will help a little, but really, you should go DC system if you want to usefully use gloves etc. And this doesn't really work with varitronic.
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Re: LI special - swansong project?

Postby jonw » Tue Feb 23, 2021 1:40 pm

dickie wrote:You need to know what power the gloves are and how much power the varitronic dc supply can provide. A battery would help, but only until it goes flat. Which I I wouldn't have thought would be very long at all. A quick look at gloves show them around 25watts. A capacitor won't help you at all. A battery will help a little, but really, you should go DC system if you want to usefully use gloves etc. And this doesn't really work with varitronic.


Cheers Dickie... cold hands it is then!!
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Re: LI special - swansong project?

Postby dickie » Sat Mar 06, 2021 7:24 pm

So, I've got a remade cable disc.

Image
Nobody wants this.

What appears to be happening is that the pads are pressed against the disc, but then the actuator arm can still be pulled back until the lever hits the bar. My drum brake is better than this!

Image

So I bought a 'better' actuator as a bit of a gamble. It's certainly nicer quality and some of the plates are thicker, but the spring is weaker and it doesn't return without a bit of persuasion. So, remembering the thread about making them serviceable I thought I'd swap the spring from one to the other and make the best out of what I have. Here'sthe link for anyone interested.http://www.ilambretta.co.uk/forum/viewtopic.php?f=10&t=12767&hilit=Actuator

To cut a long story short, the stronger spring is now lost somewhere in my garage. Bollocks. So, I'm going to try adding a preload washer, and will be ordering some different strength and length springs to try. Will be easy to swap them around now that I've added a screw instead of the peaned pin.

Here's some pics to compare the actuator which came with the disc and the one I bought to cure it, but didn't.

Better quality one at bottom.
Image

Better quality on right.
Image

If anyone has any great ideas I'm always willing to learn.
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Re: LI special - swansong project?

Postby Storkfoot » Sat Mar 06, 2021 8:30 pm

Is there any reason why you have left the spring off the adjuster clamp?
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Re: LI special - swansong project?

Postby dickie » Sat Mar 06, 2021 9:03 pm

Storkfoot wrote:Is there any reason why you have left the spring off the adjuster clamp?


Not a good reason. Just that it's been on and off a dozen times and I've forgotten to put it back. I'll put it back on next assembly.
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Re: LI special - swansong project?

Postby Storkfoot » Sat Mar 06, 2021 11:37 pm

I have done a few reverse pulls on both drums and discs.

With discs, adjust the pads so they are tight on, then release the adjuster (the one on the fixed windows side of the hub) slightly.

Have you got the thicker front disc cable, or just a normal one? The thicker one is recommended as is covering the bottom part of the cable outer with petrol pipe. This stiffens it up and channels the energy into the braking and not flexing the cable.

Make sure the discs themselves slide in their channels. I think on everyone that I have done I have had to take a file to the edges of the disc. A small dab of copper grease on the back of each disc is a good idea.

I am not sure those bubble grips are a good idea. If you persist with them, you’ll need to make sure your brake is always properly adjusted. The last thing you need in an emergency stop situation is for your lever to come hard against the bubble grip before your brake is fully on.
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Re: LI special - swansong project?

Postby dickie » Sun Mar 07, 2021 7:28 am

Storkfoot wrote:I have done a few reverse pulls on both drums and discs.

With discs, adjust the pads so they are tight on, then release the adjuster (the one on the fixed windows side of the hub) slightly.

Have you got the thicker front disc cable, or just a normal one? The thicker one is recommended as is covering the bottom part of the cable outer with petrol pipe. This stiffens it up and channels the energy into the braking and not flexing the cable.

Make sure the discs themselves slide in their channels. I think on everyone that I have done I have had to take a file to the edges of the disc. A small dab of copper grease on the back of each disc is a good idea.

I am not sure those bubble grips are a good idea. If you persist with them, you’ll need to make sure your brake is always properly adjusted. The last thing you need in an emergency stop situation is for your lever to come hard against the bubble grip before your brake is fully on.

Thanks storkfoot, a few things there for me.

Yes, j had to file the edge of the pads to let them move freely (I think this is what you mean),but I also opened the holes.in the disc slightly too.

I'm not sure that it is a thicker cable, but is a flat coil type rather than wire. I think I have a thicker inner cable somewhere, so that's worth a shot. Although to be honest, I think the problem is in the actuator. The reason I
say this is that the arm is moving,, which tells me.that there is something flexing inside the brake itself rather than the cable route. But, I'll give it a go anyway.

What you say about the.grips is pretty obvious really. I should have realised, but they are very comfortable. They might find their.way to.the bin.

It's a bit disappointing compared to my reverse pull drum. On that, I can out brake my mate with his external disc.
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Re: LI special - swansong project?

Postby Warkton Tornado No.1 » Sun Mar 07, 2021 4:21 pm

To be brief (for once :roll: ) This is just what I do & works for me, although some is obvious & already will have been stated:

Pads should just move freely & be Copaslipped back & sides

The static pad adjuster should be flat bottomed, ground back if necessary. The core of the M8 SHSS is even then only 6.8 mm

The disc bore & pins should be free to slide & also Copaslipped

The cable fitted spring between actuator & backplate lug should be fitted & under compression, being replaced by a longer/stronger one if necessary as long as it cannot become coilbound

Get the stoutest inner/outer cable that you can. Even the thicker 2.5 mm inner assemblies have stretch/spring in them which all contributes to lost motion. Personally I have contacted cable manufacturers about the prospect of as-thick-as-we-can-accommodate-assembly with no joy. Surely that must be a challenge for somebody?

Pads take a while to bed in by wearing to the disc. Give them a chance

Balloon grips are comfy but......it's already been said.

Measure the actuator spring gauge, diameter, pitch & compare with OEM. 'We' can look to see what 'we' have, or can buy that will fit with the same or better rate. Getting coilbound is an issue, so gauge as well as pitch are likely to be greater. But I like your thinking. As I type this, I'm also considering that if the actuator pin has a good thread & high tensile fastener in it, the retaking washer for the spring could even be shimmed outboard a tad to obviate any problems encountered with a beefier spring.
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Re: LI special - swansong project?

Postby dickie » Wed Mar 10, 2021 9:14 pm

Ok folks, I've been experimenting with various springs and a preload spacer. The first one in the photo is the 'too weak' one that originally came with the brake. The others are all from Ebay.
Image

It was immediately obvious that the 29 x 4.0mm would be coilbound, so I didn't even try it. The 29 x 3.25mm was good enough. The best was the 24 x 4.0mm so that stayed in and is on the bike now; it's a big improvement and well worth the effort.

The sponginess is still there though and I'm at a loss as to the solution. The common consensus on these is cable stretch but I'm certain that this isn't the problem. I can measure the amount of cable movement at the lever and at the actuator and it only differs by 1mm. The balloon grip might not be helping but even having no grip on at all, the lever still comes all the way back. Something is flexing within the actuator or hub. Or, the cam profile on both actuators is too 'tame' and not displacing the pad enough.

Do original disc brakes come all the way to the bar? I've never had one.

If anyone is interested, here's how I fitted a spacer. It's just a random washer I had which was 2mm thick. This actuator is also good now in terms of spring strength anyway.
Image
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Re: LI special - swansong project?

Postby Warkton Tornado No.1 » Thu Mar 11, 2021 3:09 pm

Great methodical work & you should not feel discouraged :D

Now the problems appear to be limited to 'lost motion' & I believe you will improve matters even more.

I would suggest the following:

The replacement spring should have ground flat ends. Admittedly, not always easy to achieve but hugely significant to ensure that the spring is seated properly, as well as removing stress raisers (incidentally, cars that have 'square cut' suspension springs because they are cheaper to produce, have them break more than the ground flat sort) Same principle applies to cable outers cut down prior to having ferrules fitted. Which reminds me that even the cable outer ferrules can lose motion by deforming if they are not the flat sort. We're talking "nat's" here (well I am!) but it all stacks up.

The whole set up is new so will need to bed in. I cannot remember what pads you are using, but I know that having used sintered both on & off track, I'll never go back to any other. A while back I tried with good OEM pads & they were awful. The pads themselves always be fit from being linished on their backs to remove any spongey paint, but I just mention that :roll:

The actuator itself will also need bedding in, but if the materials/hardness are not as OEM, then there will be some lost motion there. I've fell foul of remade clutch centres deforming as a spring, causing drag, but they spring back to size! Difficult to diagnose but a revelation when I did......

The cable outer needs to be as short as possible. Almost too short!

Cable adjusters need to be the strong, stout (M7?) type & the lock nut tightened up.

Even the radius of the inner cable where it is clamped has an effect through needing pulling out when the brake is actuated. I usually apply mole grips top & bottom to squige the radii tighter.

One last thing that you shouldn't need to do on a road brake, but I do on hydraulic race set ups is to replace the static pad adjust screw with shims/washers.

I hope that helps ;)
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Re: LI special - swansong project?

Postby dickie » Thu Mar 11, 2021 8:53 pm

Thanks, all help appreciated.

I borrowed my mate's original actuator and it's night and day!

Not 100% sure if it's flex within the actuator or a less aggressive ramp. I'm tempted to source an original one, but I'm sick of spending money.

The pads are sintered. Like you, I've been using them on the track for years and won't go back now.

I think it will improve with some bedding in, but it enough to keep me happy. I think I'm just going to have to have a few cans and order an OE one.

Maybe I should just give my mate one of these shiney new remade ones and tell him I've refurbished his shitty old piece of crap.
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Re: LI special - swansong project?

Postby dickie » Thu Mar 11, 2021 8:58 pm

Mark, I did file flattened ends onto the springs. Not as.good as I'd like as to do that i need to bend the ends down and i just don't know how I can do that. But they're not just square cut.
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Re: LI special - swansong project?

Postby Warkton Tornado No.1 » Fri Mar 12, 2021 1:41 am

dickie wrote:Mark, I did file flattened ends onto the springs. Not as.good as I'd like as to do that i need to bend the ends down and i just don't know how I can do that. But they're not just square cut.


It takes some practice to get right. The spring ends get to glow hot as you're doing it.
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Re: LI special - swansong project?

Postby Warkton Tornado No.1 » Sat Mar 13, 2021 1:26 pm

Apart from the inferiority of the actuator, which you have improved, I can only make one more suggestion that may help, though you may have done this automatically ;)

Prior to cabling, the static pad should be tightened so that the disc is literally locked. Then the M8 screw should be backed off a tad to release & locked so the disc just spins. This procedure will ensure that the balls within the actuator are on maximum cam ramp (I think :? ) though I suppose the next size up of balls (Ooooer!) would help further :!:

Then the actuator can be cabled up, preferably with spring/springs over the inner which helps the return even a tad more. A gaiter can be fitted later when the set up is something like right. Probably the only time the horrible, too stiff remade cable gainers are of any use!

I suppose what you are experiencing is indicative of just how far the quality of remade parts has sunk :cry:

I have no more brains to rack with this one.....
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Re: LI special - swansong project?

Postby dickie » Sat Mar 13, 2021 10:55 pm

Thanks for your input. I now have 3 different types of actuator to hand including one original one. I'm not prepared to strip the original one as it works beautifully and it isn't mine. There's an original one on its way to me now and it will be stripped when I get it.

Me and a mate spent an hour or so comparing them in remade and original hubs and have made quite a bit of progress. To the extent that I'm considering getting some quality ones made. There are loads of things that have been so badly done on even the expensive 'quality' one.

When I've got full facts and less wine in me, I'll try to summarise.
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Re: LI special - swansong project?

Postby Storkfoot » Sat Mar 13, 2021 11:19 pm

Have you replaced the bearing, Dickie? It’s not the answer to your problems, I was just intrigued as to whether you had when you had gone to such trouble to replace the spring.

My rebuilt actuator hasn’t seen the road yet sadly. Hopefully, it will at some point in 2021 :D
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Re: LI special - swansong project?

Postby dickie » Sun Mar 14, 2021 8:32 am

Storkfoot wrote:Have you replaced the bearing, Dickie? It’s not the answer to your problems, I was just intrigued as to whether you had when you had gone to such trouble to replace the spring.

My rebuilt actuator hasn’t seen the road yet sadly. Hopefully, it will at some point in 2021 :D


No, it's brand new.

I doubt on an original you'll have any of these problems, but do you have any good photos of the dimples where the loose balls fit? Those and the shape of the 3 'lugs' seem to be the main issues to resolve.
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Re: LI special - swansong project?

Postby Storkfoot » Sun Mar 14, 2021 9:57 am

Image
Image
Image
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Re: LI special - swansong project?

Postby dickie » Mon Mar 15, 2021 7:43 pm

Thanks storkfoot. That seems to confirm what I was thinking. The dimples in your actuator seem to be conical whereas on both of my remade ones they are 'radiused' and therefore the movement at the start of stroke is minimal and increases as you pull the lever. This is the opposite of what you want.

I can check for certain when my original one arrives but here's a picture of my remade ones.
Image

If you look at the cheaper one on the left, you can see ridges in the dimple; you feel these at the lever as a jerky movement in comparison to the other.

Also, both provide a less linear movement at the pad than the original one.

I'm also pretty certain that the stronger return springs are only required because the 'lugs' on the plate that moves in and out of the hub are too big and cause excessive friction on the return.
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