Standard Front Brake Upgrade

[crazy steve]

An interesting bit of fallout from my FJ fork swap ala Phil is my choice of late Harley 4-piston calipers. Just for grins, I took a look to see how they'd fit the OEM standard fork...

These would be pretty easy to swap onto any standard front forks. You have to widen the calipers (the HD rotor is only .2" thick vs the XS .27") but a fabricated plate from some .080" aluminum will take care of that, spot-mill .075" off the caliper mounting bosses, fab a simple bracket out of 3/8" aluminum plate and bolt 'em on. These are readily available (dual disc '00-03 Sportster, '00-09 everything else except V-rod), they clear the wheels with room to spare, and will double your pad area. The stock brake lines will work too. Except for the milling (easily done at any machine shop), all the rest could be done at home with a drill press and various hand tools. If you're careful, you could skip the drill press.

If anybody's interested, I'll post some pics...

'78E original owner

[WMarshy]

Hey Steve, whats the prognosis with using them on the FJ forks, same outcome? Dont hold back, of course we wanna see the pics. Sounds like a tech tip to me.

[DGXSER]

IMO, anything that can increase the stopping distance of these bikes is a welcome addition. Maybe a mounting plate of some kind can put them on a special.

[crazy steve]

Ok, heres some pics... we'll see if my usual ineptness will control here when I try to post the pics...





Whoo Hoo! It worked! Ok, the top pic show the two calipers, one disassembled. The 'spacer' is in the top of the pic. This nothing more that a bit of .080" thick aluminum cut to shape. I haven't finished the outside exposed edge yet, I'll do that when I polish these. You can compare pad size too, as I included a stock XS pad. I do need thicker seals to seal the two halves, I'm going to make those out of this:

http://www.mcmaster.com/#epdm-rubber-tubing/=6rvoiv

The bottom pic show how these fit. The two mounting point on the HD calipers need to be milled as said, then a bracket in this rough shape will do it...

'78E original owner

[jmnjrpa]

Keep

us posted Steve. That looks like a good idea with some real braking power.

[crazy steve]

I should also have mentioned (and will before somebody asks ) that Harley uses a 11/16" bore master cylinder on the dual-disc models, same as the XS, so no issues with that. You'll have to acquire the two HD mounting bolts for each side, as well as banjo bolts that fit as the thread is different. The banjos are the same size so the stock lines will fit.

I'm not mounting these to the stock forks though; somebody else will have to blaze that particular trail. I'm using these on FJ11 forks and the mounting will be a bit different. I can't say just how just yet, as I'm still waiting on my 'new' axle to do the fit-up....

I do have one question if anybody has tried them; will metallic pads work on the XS rotors? The stock HD pads are metallic, but organics are available.

'78E original owner

[WMarshy]

Any change these will work with the FJ forks that easy? The look nice cant wait for the end product. About that tubing, its not going to come into contact with any break fluid? It probably wont hold up to is since it says its just weather rated, but Im sure your all ready on top of that though.

[crazy steve]

Any change these will work with the FJ forks that easy? The look nice cant wait for the end product. About that tubing, its not going to come into contact with any break fluid? It probably wont hold up to is since it says its just weather rated, but Im sure your all ready on top of that though.

The bracket for the FJ forks is going to be a bit more complicated, I just don't know by how much yet. Yes, that tubing is to seal the fluid passages between the two caliper halves, but 'epdm' rubber is rated for brake fluid which is why I selected it. If you noticed, it's rated for glycol and water, and brake fluid is based on polyethelene glycol stock. And oh yeah, the size needed is 7/16" OD.

'78E original owner

[WMarshy]

Cool Steve, any good way to remove the vial "Harley Davidson" engraving from the caliper?

...Or did they resort to stickers to lower production cost.

[crazy steve]

Update!

I thought I'd update this after talking on the phone to these guys: http://www.truedisk.net/

The big obstacle to this swap is the difference in rotor thickness requiring mods to the caliper. Truedisk can resurface the OEM Yamaha rotors to the HD thickness (allowing an unmodified caliper), and even decide which side to take how much off of. If you just do a 'cleanup' pass on the outer surface, then remove the balance from the inside of the rotor to the stock HD thickness, this becomes a near bolt-on. You can even eliminate the spot-facing on the caliper by using a .075" spacer (a washer would work) between the fabbed bracket and the forks. Cut the bracket out, drill it in the right places, and bolt these on.

[natemoen]

Have you done this on anything yet or is it just thought so far?

[crazy steve]

As far as actually putting these on a set of Standard forks, no. All I've done is mock them up to see what would be involved. These measurements are accurate though, so you could use this info to install.

I have completed mounting these to my modified FJ forks, but can't upload any pics right now as my 'puter won't take them for some reason.

I sent you a PM too...

[ManagerMike]

I do have one question if anybody has tried them; will metallic pads work on the XS rotors? The stock HD pads are metallic, but organics are available.

'78E original owner

Metallic pads will work, however they will wear the rotor more than the organics due to the metal content. The organics also stop better (higher friction coefficient).
Why do they make metallic pads then you ask? The metal content helps them to dissipate heat better than the non-metallic pads resulting in less brake fade at high brake temperatures, like when twisting through the road course at 100 mph with the titanium knee pads.
Unless you live in mountainous terrain and/or frequently go from one hundred to zero in 2.3 seconds (with stock eleven brakes), use non-metallic pads whenver you can, even on your cage.
The only better optoin is ceramic pads, they combine the best of both of the other two technologies.

[cywelchjr]

As far as actually putting these on a set of Standard forks, no. All I've done is mock them up to see what would be involved. These measurements are accurate though, so you could use this info to install.

I have completed mounting these to my modified FJ forks, but can't upload any pics right now as my 'puter won't take them for some reason.

I sent you a PM too...

I think Geezer was working on an adapter plate to put R1 (I believe) calipers on standard forks, and I believe that no other mods were needed to make them work other than the adapter. I think you need a different MC with the R1 calipers thought.

[cywelchjr]

I do have one question if anybody has tried them; will metallic pads work on the XS rotors? The stock HD pads are metallic, but organics are available.

I have run metallic pads on both front and rear on my 80G with the only issue being I didn't care for the squeal of they gave me. But I have better stuff so I'll be putting Vesra Metallics on the front next (just put a set on the back last weekend and so far I'm pleased with them, much better than the Pyramid sintered pads I had on previously).