My BMW fork and Brembo radial brake swap!

[BigSherm]

I’ve been working on this for a while!

The research of which parts to use was by far, the most time-consuming part of this project.

Forks from a 2017ish BMW R1200R are as near to identical to the beefy size and length of the stock Valk forks as I can find, and they have quite better damping with 20wt fork oil, cut down heavy duty Progressive springs meant for a Valk, and 1” preload spacers.
I used aftermarket Brembo huge 330mm brake discs meant for an Aprilia RSV1100 V4 because Aprilia’s bolt mounting pattern is very close to the stock Valk front wheel.  I only had to redrill and tap the Valk wheel for 8mm holes, in a 2mm larger bolt circle, and have 7mm rotor spacers made to get the correct spacing between rotors.
I used Brembo radial brake calipers from a 2018 Kawasaki ZX10R with the stock Valk master cylinder, and with 5mm caliper spacers to allow for the larger discs.
I have Gl1500 Progressive air shocks that raise the rear quite a bit, and the setup is really fun in the curves!
The ride is firm and controlled, and the brakes are incredible.
Sherm

[Bagger John - #3785]

Neat work.

Are there any wheels that could be used off-the-shelf (no mods required) for a conversion?

[hubcapsc]

Needs more pictures  ...

The fellers at Traxxion can change out the internals of our forks
with their cartridges, but what you did sounds like it was fun
and works good...

-Mike

[Bagger John - #3785]

The fellers at Traxxion can change out the internals of our forks
with their cartridges,

One set going this year; the other, next.

[BigSherm]

Hey John,

Since our forks are so wide, I don’t think there are any front wheels with big brake rotors spaced wide enough for us.
320mm are pretty common front rotors on sport bikes, but I think there’s even less of a chance that a wheel could be found with the 330mm rotors I wanted.
You could always spend big money and get a perfect solution made, but I was trying to repurpose things already commonly available and avoid spending big.
Just a few Ducatis, the Honda CBR929/954, and the Aprilia 1100 V4 are the most common bikes I know of with 330mm rotors.
It would be pretty simple to use one of those front wheel and brake rotors, with some simple spacers between the rotors and wheel to space them out.
Even though our Valks have a huge front tire, the Valk front wheel is 17 x 3.5”, which is a typical sport bike front wheel size.  I did think about that, and the very heavy Valk on a very light sport bike front wheel is a little bit of a concern.
You’d more than likely need to install wheel bearings with the correct inside diameter to match our front axle, too.
Rather than get a new axle made at significant expense to match the BMW forks, I had an adapter sleeve made for one end of the Valk axle to fit the BMW fork axle clamp.  Luckily, the other end of the axle matched the BMW fork.

Scott

[Bagger John - #3785]

Way back when, I had Cruise Concepts (PR) and their mainland-based operation (Troup Machine, in TX) machine a set of solid wheels for my I/S. These were delivered, put in storage and never installed. I now have other plans for them (namely, a Standard) but the fork project got me thinking about the custom wheel aspect and some possibilities.

Viking and at least one other vendor I'm aware of used to machine Valk wheels after Cruise closed up shop. If one of these outfits had a program for the different rotor-bolt circles and other differences, it would be relatively easy to get a custom front produced on a 5-axis mill.

If I still had access to the Milacron I did, making them would be trivial except for material, tooling and coolant expenses.  

[Jess from VA]

This is pretty interesting and thanks for sharing.   

The Valk brakes (mainly fronts) have always been written up as among the best (and tested high in stopping power comparisons, though back in the day).  With good fluid, pads and caliper service, my brakes have always been outstanding.  Any better, and I could go over the handlebars.

Valk forks, though huge and well built, can get soft and mushy and leaky over time.  Cutting down on the leaky would be nice.  But I wonder if this is something that happens with all 20yo bikes?

[Bagger John - #3785]

Valk forks, though huge and well built, can get soft and mushy and leaky over time.  Cutting down on the leaky would be nice.  But I wonder if this is something that happens with all 20yo bikes?

I'll say that I got VERY good at rebuilding GL1100/1200 forks due to the occasional leaks with the ones I had.

[hubcapsc]

This is pretty interesting and thanks for sharing.   

The Valk brakes (mainly fronts) have always been written up as among the best (and tested high in stopping power comparisons, though back in the day).  With good fluid, pads and caliper service, my brakes have always been outstanding.  Any better, and I could go over the handlebars.

Valk forks, though huge and well built, can get soft and mushy and leaky over time.  Cutting down on the leaky would be nice.  But I wonder if this is something that happens with all 20yo bikes?

Valkyrie forks seem OK with Progressive springs, but with their $ saving
single cartridge made out of a stamped tube, they could be a lot better.
Mine have Progressive springs and suit me fine.

All unmaintained 20 year old forks are mushy and leaky    ...

-Mike