New 6 pot Caliper Upgrade

JustMike
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New 6 pot Caliper Upgrade

Post by JustMike »

I was asked if I fancied starting a new thread on my upgrading to 6 pot calipers. I hope I`ve covered all you need to know Steve.
When I first had a CBX back in 83 it pained me how bad the brakes were and I upgraded to calipers off a CB900F.
I had never forgotten how bad the brakes were and when I got my current bike last year it all came back to me that the brakes were as bad as I remembered.
Being that we`ve moved on a few years from 1983 it isn`t so easy (impossible) to get the required parts to do the upgrade that I did the first time round, so it is either buy new modern calipers which are not cheap or suck it up and live with whats on the bike.
The way I ride meant that I had to seriously consider new calipers.
On searching the internet I had found a company in the UK who specialize in making bespoke calipers for road or racing application, Pretech.
http://www.pretech.co.uk/shop/index.php ... ory&path=6
The calipers cost £336 each or $423 so a big outlay. But if they save my ass just once I`ll consider them well worth it.
The good thing about them is that they are a direct bolt on replacement for the originals, but I must point out that I`m talking about my own 79 CBX. I don`t know about the Pro-Links.
On receiving the calipers the first thing that I see is the quality. Very well made and anodised in your chosen colour. This causes a slight delay in delivery as they are batch anodised so may have you waiting a week or 3.
7847 7849 7850
Like I said they are a straight bolt on replacement and so I had no issues fitting them.
The brake pipe banjos don`t line up properly as they are twisted 45 degrees out. With the original rubber pipes this is not a problem as there is more then enough flex in the pipes to allow me to twist them into position.
Time to bleed them. And this is where I did find a problem. I couldn`t get one caliper to bleed unless I loosened the banjo bolt to release the air. On contacting Pretech who were extremely helpful he explained what the problem would be and offered to take the caliper back to fix it, and told me how to do it if I wanted to do it myself. I elected to do it myself as it should be a 2 or 3 minute job. I haven`t done it yet lol.
Okay calipers are bled and the feel at the master cylinder has improved. Gone is the horrible spongy feeling that floating calipers cause at the lever and it is now a firm solid feeling.
I was worried about how the standard master cylinder would cope with the new calipers, but so far my fears have been unfounded.
When out on the road the brakes feel exactly like original. It is only when you grab a bit more brake that you feel the front wheel begin to dig in. The harder you pull the more she slows, and no hint of fade or that need to quickly find a big anchor to chuck out the back.
The pads that come with the calipers are EBC organic pads, so they shouldn`t be too hard on the discs. I did notice they have a tendency to squeal a little and have also read elsewhere that others have found this too.
Probably if I were to upgrade to braided lines and/or get a larger master cylinder from say a Fireblade the braking performance would take a larger jump. But at the moment I am happy with how they are.
One other issue I had was the fitting of the speedo cable. The caliper gets in the way, but I found a way around it.
If you loosen the axle clamps you can turn the speedo drive down a little which will allow the cable to loop under the caliper. The downside of this is that you end up with the cable being about 3 inches too short and it wont reach the base of the speedo. I was able to buy a 6 inch speedo cable extension online. To save any hassle in the event that they might unscrew and you lose your cable I recommend a small cable tie under the head of the main cable to hold it to the headlamp bracket behind the fork leg.
7848 7846
The hardest part of the conversion for me was getting those bloody screws out of the master cylinder cover. But I think we`ve all been there at some point.

Mike

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Re: New 6 pot Caliper Upgrade

Post by Larry Zimmer »

Excellent! Thanks, Mike. Good looking, too.
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Re: New 6 pot Caliper Upgrade

Post by JustMike »

Larry Zimmer wrote:Excellent! Thanks, Mike. Good looking, too.
Your most welcome Larry.
Yes they look rather nice once fitted.

Mike

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Re: New 6 pot Caliper Upgrade

Post by AshishNJ »

So, have you had some good riding after this upgrade ? I am assuming those are 79 rotors.
Would like to know how is the brake wear and how do you feel about them compared to bikes from late 90s :) .

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Re: New 6 pot Caliper Upgrade

Post by JustMike »

AshishNJ wrote:So, have you had some good riding after this upgrade ? I am assuming those are 79 rotors.
Would like to know how is the brake wear and how do you feel about them compared to bikes from late 90s :) .
I have only recently fitted them so it is too early to know about any wear issues.
They are easily better than the originals. As I said they feel the same but when you give an extra squeeze you feel that extra power.
These calipers are also supplied for race bikes so that should let you know how good they are.
At the moment I`m still using the original master cylinder and rubber brake pipes. Upgrading those would make a big difference I`m sure.
So far I`ve had no complaints.

Mike

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Re: New 6 pot Caliper Upgrade

Post by cbxchris »

Looks good Mike, are you using standard fork springs and oil ? would be nice to know how std copes with the extra braking power, especially in an emergency situation, i recently had a car pull out in front of me, went for the brakes, and they just hauled me up, it was then i wished i was on my modern bike ! :o

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Re: New 6 pot Caliper Upgrade

Post by JustMike »

I have no idea on what has been done to the front end Chris.
The bike had been used quite regularly by its original owner in the US until about 2009, it was then shipped over here and had some work done on it and then I got it.
So I don`t actually know if fork oil has been changed, or the fork springs.
The front end is quite firm but it doesn`t feel particularly stiff like I would expect in an upgrade.
I hope never to need them in an emergency, but I`m more confident in them than I would ever be with the standard calipers.
I am a heavy braker and have had no concerns with them so far.

Mike

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Re: New 6 pot Caliper Upgrade

Post by Warwick Biggs »

They would have to be a huge improvement on the originals Mike but the situation with the Prolinks is as you inferred, very different.

For a start the stock 4 pot calipers on the Prolinks are much more effective than the single piston units on the early models even with the rather silly and novel vented SS rotors. The early floating brakes on the Prolink are pretty good but can be improved by replacing those vented rotors that weigh a ton and make quite good boat anchors but not m/c anchors. Way too heavy. If you know somebody with a lathe it is not hard to have a set of cast iron rotors run up that will improve braking AND reduce un-sprung weight significantly. You can make them much thinner and use spacers behind the pistons to make up for the reduction in width.

If you search around on the web you can find HH sintered pads that will fit and give you excellent braking, good enuf' for racing and more than adequate for road use even if you work them hard. For racing there are a multitude of other improvements that can be made to the brakes while still retaining the stock Prolink calipers. I personally believe that these Honda calipers are better than the single piston Brembos that are pretty much ubiquitous in historic racing.

Of course this raises issues with the front springs, damping and tyres because they will need upgrading as well and you are already on the slippery path to a modern bike. Once you start fiddling with old bikes it can become hard to know when to stop.

Rick.

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Re: New 6 pot Caliper Upgrade

Post by wyly »

Six pots would a great upgrade but the cost is more than I can justify. My upgraded four pot system salvaged from a later 750F were low cost and provided a significant improvement in stopping. Upgrading old rides has a financial limit, at some point buying a new bike becomes a more sensible option, where that limit is is very much a personal decision. Other than a pair of Ohlins I've reached the end for major modifications, and even the Ohlins are of questionable value for me.

Not long ago I was in bike shop for an emergency tire repair and another customer began criticizing my 79's handling short comings and what I should do to bring it to modern standards, if I wanted the latest technology I'd buy a new KTM900. As it is my 79 handles well enough for a 41 yr old super bike(with a few 80's upgrades and Racetech suspension kit) and I ride it well within it's limits.
Last edited by wyly on Sun Dec 15, 2019 12:11 pm, edited 1 time in total.
CBX a work in progress, still improving...GS1150EFE completed and awaiting modifications.....RD350, remnants in boxes scattered throughout the garage

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Re: New 6 pot Caliper Upgrade

Post by EMS »

wyly wrote: Upgrading old rides has a financial limit, at some point buying a new bike because a more sensible option, where that limit is is very much a personal decision. Other than a pair of Ohlins I've reached the end for major modifications, and even the Ohlins are of questionable value for me.

Not long ago I was in bike shop for an emergency tire repair and another customer began criticizing my 79's handling short comings and what I should do to bring it to modern standards, if I wanted the latest technology I'd buy a new KTM900. As it is my 79 handles well enough for a 41 yr old super bike(with a few 80's upgrades and Racetech suspension kit) and I ride it well within it's limits.
Excellent reasoning! I wish everybody would approach it like this. We would see less 'hacked up" bikes!
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Re: New 6 pot Caliper Upgrade

Post by Rick Pope »

EMS wrote: Excellent reasoning! I wish everybody would approach it like this. We would see less 'hacked up" bikes!
That's what led me to buy a used CBR-XX, rather than hotrod a CBX.

OTOH, I can see how some feel the original manufacturer left the job unfinished, so upgrades are made, sometimes without limits.

Diversity is a wonderful thing. :-)
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Re: New 6 pot Caliper Upgrade

Post by Larry Zimmer »

One guy's take on these type things: It's a hobby. By definition that means putting $$ into it just for the fun of doing it. As Rick and others mentioned, if you truly are just trying to achieve 'modern' sport bike performance, there are great bikes on the used market, for less $$, that no mods can match. As that one old saying is: "It isn't about the destination, it's about the journey". Have fun, all!
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Re: New 6 pot Caliper Upgrade

Post by Warwick Biggs »

Here, here! I agree. The performance of modern bikes is already exceeding our ability as humans to exploit their full potential. The G forces generated by my modern Gixxer track bike on the race track severely test my physical capacity and I'm a fairly fit and experienced motorcycle racer.

On Moto GP bikes young riders like Fabio Quatarraro are now routinely undergoing operations to modify their arms and vascular systems to deal with "arm pump" caused by excessive G forces.

When we have to modify our physiognomy in order to operate our machines, I think you could say we have reached a limit of sorts, on the quest for improved performance

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Re: New 6 pot Caliper Upgrade

Post by JustMike »

I`ve not been on for a while so just been catching up on the comments.
I must stress that I have no intentions of upgrading or hotrodding my CBX.
Modifications have been limited to a 6 into 1 exhaust so that I can keep the original system safe.
Also I replaced the original rear shocks with a set of standard looking Hagon shocks which are just as bouncy as the originals.
The front calipers have been changed because the way I ride I need good stopping power and quite frankly the original brakes are rubbish.
But I knew they were bad as I have very fond memories from back in the 80`s of running wide on bends or not being able to stop on time for turns etc.
They were not cheap to buy at £700 UK. But if they stop me from running wide on a bend just once, they have paid for themselves.
So modifications can be done to improve things without turning a bike into a hotrod, and the way I`ve done it I can have my bike back to fully original in a couple of hours.
Now my other hack gives me all the power I need if I ever find the CBX lacking. A Triumph Rocket 3.

Mike

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Re: New 6 pot Caliper Upgrade

Post by Warwick Biggs »

Well I'm sure they are an improvement Mike and they look good too. However, for others looking for a more economic improvement I would suggest simply upgrading to the Prolink 4 potters.

If you want you can achieve race standards by replacing the vented Prolink rotors with a much lighter set of Honda VTR rotors. Because they are thinner and drilled you will need to make up some light alloy spacers to insert behind the pistons. Then fit HH sintered brake pads. This mod will provide superior braking to the Brembo single piston brakes typically run by historic racers and will be a vast improvement on the original.

It won't stop as quickly as a Supermono with 8 piston brakes but it will stop very quickly indeed and with good feel at the lever too.

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