[sdaniels]

After replacing nearly every piece of the front brake on my sons bike trying to figure out why they sucked so bad I found posts from other message boards showing setups with different rotors & calipers with adapters. Here's what I did. Bought a used stock rotor, removed the rivets to get to the carrier. Inside radius of the new rotor was smaller so had to grind down the carrier a bit. Drilled/tapped each hole on the carrier to 8x1.25.

 

[sdaniels]

One forum's post showed someone using a Kawasaki EX500 rotor. It has the same bolt spacing as the carrier on our bike. It's 282mm. I measured & came up with 298mm possibly fitting. Figured if I was going to do this, may as well get the most out of it. Picked up a late model Vmax front rotor, bolted it to the CB carrier & prayed it wouldn't interfere with the lower mounting point on the fork. It's tight but there is clearance.
View attachment 280450

 

[sdaniels]

Next was the caliper. I picked up a Honda Fury caliper, zip tied the caliper to the fork to hold in place, bled them. Once situating the caliper exactly where I wanted it, I zip tied the brake lever to hold in place & started measuring spacing between bolt holes. I got extremely lucky with my first mockup. I used 1/4" plywood & a jigsaw. Everything lined up perfectly. Almost forgot...I drilled through the bolt hole for the lower mount of the stock brake arm. Grinding down that tab was a bit of trial & error. Getting it perfectly flat & figuring out the right size spacer is necessary to keep the caliper parallel to the rotor. It would bind if it wasn't. I ground it down using a palm sander to get most of the bump out then a cutting wheel on a dremel to fine tune it. Ended up with a 17mm, 1/8" thick spacer.

 

[sdaniels]

Adapter cut out of 6061 1/4" aluminum

 

[sdaniels]

Final setup. 258 to 298 rotor & the entire setup cost around $140. Used rotor & caliper, new brake line with 3AN banjo fittings, 8x8 1/4" aluminum plate & various bolts. Whole setup weighs within a few ounces of stock. I was already using an 11mm master cylinder from a VTX1300 so I didn't add that into the cost here.

 

[Alan F.]

looks great, how's the feel and feedback?

 

[sdaniels]

I only have about 10 miles of use so I'm a bit limited on details. Pads still need a bit of breaking in but I did get a few hard pulls in. Stopping power is so much more pronounced but it's not grabby. I'm not even sure what pads are in it...could be organic but even if they are I can live with them. Feels linear, the more you squeeze the lever the harder it bites...stock setup had very little initial braking & squeezing the lever harder didn't do anything. The caliper has a pair of 27mm pistons. With the 11mm master cylinder it gives a 12:1 ratio, which is what I shoot for on single disc setups. It's almost exactly the same ratio using the same master cylinder with the stock caliper but way more stopping power.

EDIT: Pads bedded. Did about 10 stops from 50mph, about a minute apart, progressing from light to heavy braking each time. The last one was a hard squeeze, emergency stop. It's almost violent how hard it grabs now. No fade at all. I've got a 1/2" master that I'm considering putting on. That would give me a 9:1 ratio, stiffen up the lever pull & would still be better than stock (7.4:1). Caliper has Bikemaster pads but I don't know if they are sintered or organic. Next thing that needs to be done is stiffer springs. It's very nearly bottoming.