Another shock thread ...

the best mod that I did to the rear shocks when racing my Monty was to stop using the rear brake when going into corners, made the whole bike a lot faster, more predictable and more stable, that brake was handy coming out of corners especially in the wet, otherwise I never used it.

I have (I think) S&W shocks on TOG, they were the ones Nickdav7 took off when he fitted his Willyerbers (otherwise known as knobwavers) decades ago, they are still fine and work well, but I am 40% heavier than him, Those S&W shocks got a massive increase in performance and feel when I fitted on the outside a pair of Koni shock stickers! you would'nt believe the conversations here and abroad after that one! the stickers are still there but a bit faded now so performance is dropping off again.

Will someone please get a very good order 750, preferably an SF2 over to Nickdav7's house so that he can have a ride, (to my knowledge he has never riden one) he will come back amazed at the steering and hadling and a rear brake that is exteremely powerfull unlike rear disc brake triples which barely work, come on be honest, yours dont do they? unless you have an RGS with ZXR rear master cylinder.
CLEM
 
JO55 said:
That’s a really good shout actually. I’d forgotten about them. Don’t they do fork kits too?(although from what I understand, the issue is with the lack of bushings rather than damper action!
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Maxton have a new fork cartridge which is a vast improvement on old. I think they fit 35mm but definitely 38mm and 41.8?mm M1R's. New have adjustable rebound damping, adjustable compression damping and preload all from top of fork or under cap if you want a std look. They are bolt in and use existing mountings so if you ever want to return to factory setup it is possible. I have recently purchased 4 sets all matched to data I supplied to each Laverda they are going on.
 
I’m fairly certain Ray Peacock’s Corsa I rode in the 85 TT had S&W shocks fitted, but whatever they were, they were many times better than the shocks on my own bike.
 
CLEMTOG said:
yours dont do they? unless you have an RGS with ZXR rear master cylinder.
CLEM
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Hi Clem, which model ZXRs? Do they bolt on to the existing mount?

Mine brings the light on, for rego checks, and can hold me on a slope if I need to take both hands off the bars to rummage in pockets.

I spent a bit of time with mine some years back, had the caliper and MC on the bench, to get the MC up higher and all that. I found when I was putting back on the bike, if I held the MC horizontal, and pumped it with a screwdriver, it would work well, but when I mounted it at an angle, it went soft ¯\_(ツ)_/¯ One of mates has a Guzzi, its rear brake MC is horizontal.
 
I think Clem might have meant the GSX-R-wheels & brakes conversion. I have a GSX-R Master & Caliper with the small GSX-R rear disc on my Jota - works extremely well. And yes, they have horizontaly positioned masters for the rear. On the 1000 SFC, I have the original Master with the GSX-R Caliper and disc - does not work well... The problem is not the position of the master, it is the size. GSX-R (and almost all jap bikes) use 12mm/ 1/2 inch masters on the rear, where Laverda used PS15 I think. Keep in mind that a PS16 on the front even gives a "wooden" feeling on the 2 x P08 Calipers, how could a PS15 ever work with one...? Not sure why they did that, maybe because nothing else was available from Brembo...?
 
The way shocks behave is of course dependent on tyres, which are in turn dependent on oil and batteries.
And the bike's colour.

Paul
 
Laverdalothar said:
Keep in mind that a PS16 on the front even gives a "wooden" feeling on the 2 x P08 Calipers, how could a PS15 ever work with one...? Not sure why they did that, maybe because nothing else was available from Brembo...?
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15 will give more power than a 16, Lothar. Less wooden. But I agree, on a single caliper, not a good combo.
 
That's why I said basically, that if a PS16 with 2 P08 connected give already a wooden feeling, how could a PS 15 on a single P08 ever work...

Assumed same travel and the same calipers, and assumed a PS 16 would be working well on 2, it is an easy calculation that assuming the same capacity of fluid needs to be transported to make the 2 pistons of the one caliper move as far as with the 16mm pump for 2 calipers, the diameter of the master would have to be around 11mm...

PS16 = 16mm, assuming a 5mm move of the piston:
R² * Pi * movement = 8² * Pi * 5mm = 1005

for one caliper, calculate: 1005 ./. 2 = 502,5
(Root of (502,5 ./. Pi)) *2 = 11mm

even with different levers/ratios etc., you could not compensate for an almost 40% to big master...

Now - 12mm on the japs bikes brakes make much more sense I would say... (assumed they have roughly the same piston sizes, maybe even bigger ones...).
Or put it that way: The more modern 4-pot calipers use a 16mm master on the two front calipers, too. twice the number of pistons, smaller ones though. They work very well...
 
Laverdalothar said:
That's why I said basically, that if a PS16 with 2 P08 connected give already a wooden feeling, how could a PS 15 on a single P08 ever work...

Assumed same travel and the same calipers, and assumed a PS 16 would be working well on 2, it is an easy calculation that assuming the same capacity of fluid needs to be transported to make the 2 pistons of the one caliper move as far as with the 16mm pump for 2 calipers, the diameter of the master would have to be around 11mm...

PS16 = 16mm, assuming a 5mm move of the piston:
R² * Pi * movement = 8² * Pi * 5mm = 1005

for one caliper, calculate: 1005 ./. 2 = 502,5
(Root of (502,5 ./. Pi)) *2 = 11mm

even with different levers/ratios etc., you could not compensate for an almost 40% to big master...

Now - 12mm on the japs bikes brakes make much more sense I would say... (assumed they have roughly the same piston sizes, maybe even bigger ones...).
Or put it that way: The more modern 4-pot calipers use a 16mm master on the two front calipers, too. twice the number of pistons, smaller ones though. They work very well...
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I thought that this was a shock thread, but...

There is a range of master cylinder area to brake cylinder area ratios which give good feel. This article offers a little insight:


I suspect it gets a bit more complicated when you are using two four-piston calipers with a radial master cylinder, and I'm uncertain if the suggested figures also apply to the rear brake.

cheers,

bazzee
 
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bazzee said:
I thought that this was a shock thread, but...

There is a range of master cylinder area to brake cylinder area ratios which give good feel. This article offers a little insight:


I suspect it gets a bit more complicated when you are using two four-piston calipers with a radial master cylinder, and I'm uncertain if the suggested figures also apply to the rear brake.

cheers,

bazzee
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Rear brake is a cable operated drum.
If it doesn't brake enough, which is never the case, get a bigger boot.
Paul
 
Paul Marx said:
Rear brake is a cable operated drum.
If it doesn't brake enough, which is never the case, get a bigger boot.
Paul
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Clem spoke about Triples with rear brake disc. Not sure that is operated by a cable or has a drum, too... ;)

Rear brake on the SF(0) I had was blocking the rear wheel on the slightest touch. Very dangerous when you are used to a factually non-working, wrong ratio Laverda disk-brake model... Rear went sidewards several times on emergency stops and almost made me crash the bike at least 3 times. To dangerous for me, sold it.
 
That has a fix, stronger springs are available that hold the brake shoes together, and that takes more effort to lock the brake. When I converted my 3c to right gear change and deleted the super long brake cable to a way more direct connection it was lethally strong, added those springs and it became much more usable and not as easily lockable.
 
Thanks, Vince, did not know about that possibility. As I found the fork to be flexing to much and to be way underdamped and the rear (Ceriani's) was completely overdamped, the front brake only half way working with brutal force and the rear blocking on the slightest touch, there would have been to much to change to make it "my" bike. The two spokes that broke even on the first few 100 km added to that... The engine was running like a dream though and the sound was awesome (but also awefully loud... but on a nice way... ;) ). The look was just lovely! The riding experience was just not mine.
 
Some serious setup issues with that SF, Lothar. My SF1 brakes were fine, rear never too touchy, front worked but like you I found it lacked power when i needed it. Like any drum brake they ideally need to be set up with close tolerance between shoes and drum (old shoes and too much clearance means the cam angle allows the shoes to 'servo' and the rotation of the wheel pulls them on - scary and worse in cold weather!). They also need to be machined as close to circular to match the drums as possible and then they wear in concert with the drum. Lastly, as Tippie said, centering the drum backing plate on the axle is absolutely essential.

All that gave me the irrits and after about 10 years on a 4LS Yamaha TZ front brake I went with triple discs.

Handling wise the SF1 was incredible. All I ever did was play with spacers for ride height at the front and fork oil viscosity and fit aftermarket shocks 9Koni then S&W which became some other company). Anyone who ever rode with me will attest to how stable the bike was at very high speeds and on any road surface, even dirt. Those 35mm Cerianis even had bronze low-stiction bushes. Superb fork for their age and of the time..
 
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