Front Brake Components

Hey, In need of a few parts that I cannot find. they are for a 83 KZ650 CSR H3

1: I need a master cylinder assembly. or at least a res and plunger. The bike did not come with one and the universal one I got is too small.
2: I need a new rotor.

Any ideas where I can find these parts? I've looked on ebay with no success.

What universal master cylinder did you get? Asking because I'm wondering how it can be too small.
I installed a mc from a Honda CBR500 onto my 81 650-CSR w Emgo Euro bars. It may not be a good choice w the stock csr handlebars.

As for a rotor, you can probably use whatever fits a KZ550. I installed the wheels & Fr brake disk from a 1980 550C Ltd.
From the cross-reference at Partzilla the 83 650-CSR Fr wheel is the same as the 550A/C models.

Also, you should replace the rear brake shoes if you don't know how old they are.

I seem to remember someone using a master cylinder from an EX500.

To clarify, the mc fit onto the bars. It just doesn't feel like it has enough pressure when I pull the lever. I can squeeze it until it hits the grip and it couldn't lock the wheel up in wet grass. I went through 3 res full of fluid bleeding them so there is absolutely no air in the system. Nothing is leaking as far as I can tell. So I'm just wondering if the plunger is too small for this bike. New pads were installed at the time I tested.

Also this is the mc I purchased.

I bet there is still some air in the system. If you pump the lever several times, does it build a little pressure?

Some but not much. I pump it 3 or 4 times before popping the bleeder. And I close the bleeder before letting go of the lever.

Sometimes a system will be harder tha h... to completely bleed. Some folks favor reverse bleeding, pumping the fluid through the bleeder, thus forcing the air upwards. Sometimes unbolting the mc from the bars and holding it vertically while gently tapping the hose and mc will knock it loose. Another trick is to pump the handle and clamp it down with a zip tie over night to get rid of the air.

A speed bleeder makes the job much easier. I installed one from Z1Enterprises.com. The auto parts store should have something.
Z1Ent >> Goodridge speed bleeder SB7100 - 7mm x 1.00 - Pkg 2

Master cylinder. The 16mm mc in the pic is for a dual disk Fr brake. The stock piston bore for a single disk Fr is 1/2" (12.5mm). The larger bore size will give a different feel to the brake lever.

How will that affect my braking? I thought a larger bore would give me more aggressive braking performance. Also. I cannot find anything 12.5mm and only found 14mm. Would that be acceptable?

I think most every single disc Japanese bike uses a 1/2 inch (12.7mm) front master cylinder.

Bore size explained