I got to think and since I will be mounting a 23" wheel I want a little extra braking up front. Did some research and found some threads in other forums and my solution is to use a Hayabusa 6 piston caliper up front and going to add one in the rear as well. Got a great deal in eBay on a set calipers, $85 for both but they need to be cleaned up. I'm deployed right now so my brother has them and getting them powder coated for me. I have a 3/8" thick T-6 aluminum plate waiting for me at home to make the brackets out of. Also have a set of assorted aluminum spacers to get the spacing right.

Since Hayabusa's are known for being crazy fast, should be some pretty good stopping power for the bike. Can't wait to get home and do some work! For now here are the calipers I'll be using. One is missing the brake pads but both calipers will be getting fresh pads anyways.

 

So the pad contact area will be on the proper radius and surface of the rotor with the busa pads and Harley stock rotor?

 

As long as you have an 11.8" front rotor it works out perfectly. A forum member over on xlforum.com used a dyna front end on his sportster along with the 6 piston Tokico's. The bracket looks fairly simple, I'll have a little more style to mine but same concept. Here's the picture of it on a 49mm dyna front end. The radius of the pads contact the correct area of the rotor, caliper may look off but it's got full contact.

 

Sweet! I agree on putting new pads on there. What is that red stuff on there? Sounds like a pretty good deal you got on them.

 

I know a busa runs a 310mm or 12.2" rotor, our 11.8" is so close you should be fine... the issue i worry about is pushing all pistons with the factory master. I know when i have done 6 pistons on other HD's the customer always had me swap masters to the 11/16... however just found this while doing some homework so you may be ok... just something to think about as you are bleeding the system

4 pot single caliper: 9/16 or 5/8 bore.
4 pot dual caliper: 11/16 or 3/4 bore.
6 pot single caliper: 9/16 or 5/8 bore
6 pot dual caliper: 11/16 or 3/4 bore

 

Wow, the result of this will be an enormous difference in braking power on that front end. I would love to have a set up like that myself, hell yeah!

I would think you would need a different piston up top, I'm sure I would find out if I were changing from my paltry single disk to your setup.

Your brakes will be tremendous, smoother I'd bet too than OEM, though easily enough to overwhelm a contact patch on a 23" wheel!

"Careful with that axe Eugene!"

Good luck, can't wait to see it completed!

 

I'll probably start with a 3/8" thick block of wood for mock up since the aluminum plate was a little pricey, it's a 12"x12" I got from www.speedymetals.com. Once I have it to where I want it I will transfer the patter over onto the aluminum and cut it out. Who know's, maybe I will cut a few out and put them up for sale.

On the setup in the picture he is using an 11/16 master cylinder since it's dual disc. The stock one should be good, if not then I'll just swap it out.

I have a 16" rim for the rear that's not laced up yet and wondering if I should get an 18" so that clearance with a 6 piston in the back won't be an issue. What do ya'll think?

 

Someone had painted them before, but both are getting blasted and powder coated anyways.

 

Luckily 11/16 master cylinders are a dime a dozen on ebay! May pick one up anyways.

 

Here's a guy in the UK that put the 6 piston on the rear. Bracket looks a little funky but same concept I'm after.