Front brake master cylinder upgrades?

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Tinman
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My Bike: Kawasaki zxr 400

Front brake master cylinder upgrades?

Post by Tinman »

So I've stuck some gsxr calipers on the 400. The brakes are now very good, but I would like to upgrade the master cylinder too.

I'm sure I've read here somewhere that a Ducati 748 master or one form and aprilia Mille will fit. I would just like clarification on which models will fit and from which years?

I've got an L model By the way

Thanks :excited
Grooveski
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Re: Front brake master cylinder upgrades?

Post by Grooveski »

The safe recommendation would be to use the master from whatever GSXR you got the calipers from.

If you're thinking radial:
At 32/34 (stock gixer four pot piston sizes) you're right up in 19mm radial territory so I'd be looking at the Nissin unit (as found on zx6r/zx14/cbr600rr and I think maybe even some of the gixers).
There's an 18mm Brembo radial used on a couple of triumphs but I'd only consider that if you prefer a softer lever with a fair bit of travel.
Don't be tempted by the R1 16mm Brembo affair. It'll not be enough m/c for your calipers - it barely handled my H model ZXR calipers with their 30mm pistons(was nice with the original L calipers - nice feel anyway - didn't fix the pads being too small).

Do be tempted by a Brembo RCS19. :smt002 The euro is weak at the moment, I picked up one a few weeks ago from Germany for 2/3 of the UK RRP(postage included). With my calipers the 18 setting is lovely and the 20 a little wooden. Your pistons are the same size as Brembo M50s so I'd be willing to bet it'd be a sweeter match and you'd be able to choose between the settings.
Even from Germany or Italy you're still looking at twice the cost of a second hand nissin for an RCS. Whether it's overkill for a roadbike is debatable but I have no regrets and don't imagine I ever will.

Mind if you fit any radial m/c you'll have to whip off the fairing & clocks and give the clock bracket a few gentle whacks with a mash hammer until the brake lever doesn't hit the bottom of the rev counter at full lock. Tilts the clocks forward a fair bit but they're still readable.
Tinman
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Re: Front brake master cylinder upgrades?

Post by Tinman »

Thanks for the reply. You seem to know your stuff!

I'm not really too keen on bending the clock bracket and I'm not that bothered about having a radial master cylinder on my bike. I just want to rid my brakes of the excessive travel and soft feeling at the lever.

I may just end up going for a gixer master cylinder then.
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Dominik
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Re: Front brake master cylinder upgrades?

Post by Dominik »

I have fitted the 18mm (?) radial brembo mc from the triumph daytona 675/ aprilia rsv4 and it does fine with the oem L calipers. The Lever doesn´t hit the fairing yet the clocks get touched on full lock. I didn´t mind and let it be, tilt the lever slightly down ('race position') and it should be enough.

Bought mine in Germany for 135€, new!
Zxr 400 SL - 130kg
zimm
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Re: Front brake master cylinder upgrades?

Post by zimm »

firmer brake lever on an L model without spending lots of money ?

fit the MC from an H model.

5/8" (15.8mm) bore rather than the L's 14mm bore.

cheap as chips, your existing lever fits and nothing fouls the clocks or looks non OE. Job done.
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Dominik
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Re: Front brake master cylinder upgrades?

Post by Dominik »

Nevertheless this are over 20 years old and there are better ones. So if you buy sth to make your bike better you should do it right, not cheap. It´s the same with zxr 750 calipers (bigger pistons). They might be slightly better than ours but shouldn´t be 1st choice...

You must have your lines (oem, braided, 2 or 3 parts) in mind, too. If the mc cylinders has those fitted inwards (like our oem) everything is fine but if the lines get mounted below it you might get struggles with the throttle. I will take a photo when it stops raining and show you what I mean ;)
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Tinman
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Re: Front brake master cylinder upgrades?

Post by Tinman »

I know what you mean dom. I've seen that HEL do a radial master cylinder adaptor, which is basically a 90 degree elbow which comes off the bottom of the master so that you can use the original style hoses. The cost of that adaptor is only £15.
Grooveski
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Re: Front brake master cylinder upgrades?

Post by Grooveski »

Dominik wrote:You must have your lines (oem, braided, 2 or 3 parts) in mind, too. If the mc cylinders has those fitted inwards (like our oem) everything is fine but if the lines get mounted below it you might get struggles with the throttle.
Yeah, the R1 Brembo was real tight. I had to loosely assemble the throttle cables and switchgear around the banjo and slide the brake clamp into position along with the switchgear. Thankfully when the pin dropped in the brake lever was at a nice angle. :smt001

The RCS fitted in much easier. The hose connector is closer to the bar so there's plenty of clearance for the cables.
My braided hose was long enough to fit the different connection angle. If a hose was only slightly short the splitter could maybe raised a little (pinch a little slack from the bottom section).
Took a pic to show how little the clocks need pushed forward. That's it at full lock.

Image

Had a look at the Brembo m/c on the Guzzi(Daytona - lovely brakes as standard) in case it was the one from the original question. It'll not be - this one's matched to 30/32 calipers.
Also checked out my mate's gixer thou' but it's not the right model. Although it has a conventional m/c it's paired to newer radial calipers and they've got smaller pistons than yours as well.
Tinman
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Re: Front brake master cylinder upgrades?

Post by Tinman »

07 zx6r master ordered from eBay. I'll post up on here once it's fitted and working sweetly.
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Dominik
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Re: Front brake master cylinder upgrades?

Post by Dominik »

Sorry for being a little late with this one. Here´s the promised photo:

Image
http://www.directupload.net/file/d/4030 ... 2d_jpg.htm

Image
http://www.directupload.net/file/d/4030 ... uf_jpg.htm
Zxr 400 SL - 130kg
Tinman
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Re: Front brake master cylinder upgrades?

Post by Tinman »

Just a quick update. I received my zx6 master cylinder today. I tried to fit it tonight but after taking the throttle assembly apart and trying various different ways I could not get the master cylinder to fit. The throttle cables are smack bang in the middle of where the banjo wants to be. I even ended up snapping the plastic throttle cable adjuster off. So a new throttle cable is on its way then I think I'll just get a brembo rcs. At least thanks to dom's pictures, I know it'll fit.
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Dominik
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Re: Front brake master cylinder upgrades?

Post by Dominik »

Theoretically the zxr also works with only one throttle cable. The spring at the carbs will 99% never get a defect so that the second cable is necessary. By removing one you gain a little more space and lose some grams ^^
Zxr 400 SL - 130kg
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Miles
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Re: Front brake master cylinder upgrades?

Post by Miles »

Second that. I've used one throttle cable for years and never had a problem.

I just give the 'carb spring' a good clean whenever I service
Tinman
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Re: Front brake master cylinder upgrades?

Post by Tinman »

Which cable did you get rid of? The one without the adjuster I suppose?
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Miles
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Re: Front brake master cylinder upgrades?

Post by Miles »

The throttle return cable. The cable that pulls the throttle back to its starting position.
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