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Twin disc conversion

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relisysxx
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Twin disc conversion

#1 PostAuthor: relisysxx » Sun Nov 19, 2017 8:06 pm

I'm thinking of upgrading the front brakes on the Z900a4 I am restoring, would I be correct in thinking the single disc is 7mm thick and the twin disc set up is 5mm? If this is right could I use 2 7mm discs or a pair from a Z650? Oh, and are early Z650 calipers the same as Z900?
Thanks in advance..........Nick

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wheelysteve
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Re: Twin disc conversion

#2 PostAuthor: wheelysteve » Sun Nov 19, 2017 8:19 pm

Just doing the same upgrade.

The correct calipers for the A4 are the front of forks mounted ones. These were only used on the B1 version of the 650. I think the caliper bodies are identical, it's the mounting plate which is handed.

The correct discs are a pair of 5mm jobs. 7mm items would also work (that's what they are on twin disc Z1 models), just a bit heavier.
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Garry.L
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Re: Twin disc conversion

#3 PostAuthor: Garry.L » Sun Nov 19, 2017 8:23 pm

Don't forget the Master cylinder will need upgrading as well.
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relisysxx
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Re: Twin disc conversion

#4 PostAuthor: relisysxx » Sun Nov 19, 2017 8:53 pm

And are z650 discs the same as z900?

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wheelysteve
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Re: Twin disc conversion

#5 PostAuthor: wheelysteve » Sun Nov 19, 2017 9:27 pm

As far as I know, the discs are the same as the early 650's , Z1000's , Z750 and some of the tripples.
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AJAyre
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Re: Twin disc conversion

#6 PostAuthor: AJAyre » Sun Nov 19, 2017 9:36 pm

Z power currently have right handed mounting brackets in stock ... the Calipers themselves Aren’t handed

John browse has some used 5mm discs in stock

You will also need to upgrade the master cylinder to 5/8 and a four way splitter one of course brake lines

Try and find a Caliper with the through bolts intact as they are hard to find and expensive as NOS

If I can be of any help PM me

relisysxx
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Re: Twin disc conversion

#7 PostAuthor: relisysxx » Sun Nov 19, 2017 11:09 pm

Thanks for the replies and info, I can get crackin now

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Re: Twin disc conversion

#8 PostAuthor: PAULJAC47 » Mon Nov 20, 2017 8:42 am

The repro 5/8 th mcs are readily available,at various prices David Silvers stock one listed for a Cb750 which is near identical or get one bored to suit, others on ebay.all Steve says is correct,dont forget the chrome brackets and four way splitter,look at using 20 w oil in forks if using 7mm discs,unsprung weight goes well up.You can use thou calipers as well though slightly different,just finishing thou upgrade meself got a box of bits left, may be able to help out parts wise..Paul J
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Re: Twin disc conversion

#9 PostAuthor: KWACKERZ1 » Mon Nov 20, 2017 1:53 pm

z650 discs are smaller than 1000’s. something like 280 mm instead of 290/300 cannot remember exactly but definitely smaller
I think i have some if thats what you are after.

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Charlie
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Re: Twin disc conversion

#10 PostAuthor: Charlie » Mon Nov 20, 2017 2:45 pm

The Z650 twin discs from the 650C are smaller, but the single disc fitments from the B models are the same as the Z1/Z9 types (IIRC they are 296mm).

You can use two of those on a Z1/Z9 twin disc conversion as long as you get the opposing caliper.

Alternatively, drop a complete Z650C front end in. You have your originals to go back to when you want originality.
Why do I persist in debating with idiots ? I really should know better :)


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