After replacing my front tyre at the weekend I noticed my original (1986 genesis) twin piston calipers on the front
were complete bullocks. A piston on both sides had seized and after much cleaning and brute force they moved
but were still far from decent. The brake lever was incredibly spongy compared to any modern showroom bike even
after bleeding the brakes.

So I quickly came to the conclusion that I should try and fit some nice new 4 piston calipers... As far as I was aware
the standard thundercat/r6 blue dot calipers could be bolted straight on to the FZR forks. However, I think the genesis
is one of the FZR400 models where this is not true , after measuring the distance between bolt holes (~90mm)
I realised that fitting 100mm spaced r6 calipers wasn't going to be as easy as I'd initially thought.

I still ideally want to get these fitted to the bike, as far as options go I could possibly replace the forks with those
of another model of FZR forks with the wider bolt spacing?

OR

as I have access to a milling machine (lathe/drill press/tools etc) I could potentially make up some kind of bracket
to fix them to?

Any ideas as to the best way of going about this would be much appreciated. Stupidly I have bought the calipers
and new pads, although I could probably sell them on without loosing out on much money, I'd like to have a bike
that can outbrake just about everything else

The first option would be the best one, and front end from a FZR 600 would be the way to go. Or a TRX850 ... or FZR400R 3EN2.
But the thing is the last 2 (and some models of the 600) will have 298mm disks and possibly 41mm dia forks so you'll need the clip-ons too, oh and the yolks.

Sooo - if you can knock up a pair of brakets it might be ... cheaper. Use a pair of braided hoses, replace the master cylinder seals (or the cylider complete) and use good brake fluid.

Out braking isn't just about the brake set up it's good a lot to do with the suspension too.

I know some R1 calipers will bolt straight on to my fzr 6 3he as came across a fzr6 3he for sale on ebay with some fitted and contacted the seller about it but dont know what year of R1 as it was long time ago i found out

OK - all the blue spot calipers on all the Yamahas are 100mm bolt spacing. Most of the FZR forks have 100mm lugs so if you measure them up chances are the blue spots will bolt straight on.

Obviously Genesis are different .... so are 3TJ (about 83mm).

If the forks on the Genesis are 38mm dia then later FZR600 will bolt in, if they're not then you need the front end.

I've got a full 3EN1 front end spare if you want it cheap :) I've just fitted a TRX/Thundercat front end to mine.

Thanks for all the replies, it's certainly helped me assess the options.

As evil chicken said braking requires good suspension too, ideally I would
use some thundercat forks, however I just can't justify spending more
money on a bike that is this old.

So I'll try and knock a bracket up for the 83mm to 100mm spacing required
during the next week (I'll be sure to post pics), however if my attempts
are embarrasing, the FZR 3EN1 (or similar) forks will be the next option I
look into.

why don't you look for some 3TJ calipers instead ???

You'll get 4 pot calipers which will give better braking due to larger pad area ... and hopefully in better condition than your originals

Evilchicken0 wrote:why don't you look for some 3TJ calipers instead ???

You'll get 4 pot calipers which will give better braking due to larger pad area ... and hopefully in better condition than your originals

It will also give you better braking because of the 4 pistons

It's the pad area on the disk that counts. Bigger area makes more friction more heat and thereforeslows the bike quicker. You have to couple that with the pressure difference as the master cylinder will be the same.
There will be a slight trade off in the wieght of the calipers but that won't be so significant.

If you wanted to take it further you could fit a different master cylinder. I've got a radial Brembo which makes the stop hard at the cost of some feeling. A reasonable alternative would be something from a newer 600, but as this bike is old you'll probably end up over spending.

Just a short update, I spent a few hours today in a workshop and knocked
some brackets up out of ~6mm thick steel. I'm fairly confident they'll be upto
the job but I'll do some testing on a 'closed road' before I start using them
as a replacement.

I'm going back to my parents on Saturday and I'll hopefully fit them, put new
fluid in/new pads and bleed the system. I will make sure to take pics!