Upgrading the brakes and suspension

 As i noticed in the very first test drive, the brakes and suspension where worn down and didn't perform that well (or at all). As one might expect the chrome of the inner-tubes of the front forks had flaked of on the area's it traveled a lot. The rear shockabsorbers were completely running dry, which makes for a bouncy and interesting ride. With the performance upgrades in mind (putting the RACER in Caferacer) a better control-able ride with more stopping power was what i needed.

While searching on-line and at swap-meets for second hand parts, it proved difficult to find appropriate length shock-absorbers. I really wanted to mount adjustable Koni's as legend says the were top-off the line in 1975 but also they have dutch roots, which makes it more fitting my build. after 6 month of frantically searching i had to settle for YSS or IKON shock that were new and a direct bolt on. Or make due with a pair of BMW R80 Koni's from the 80's which were to long (koni: 7610-1285). And of course this is what i ended up doing.

Modifying the shock absorbers

The Eye to Eye dimension what 15mm off, and the preload of the spring was to high. So i started disassembling the shocks (in fear of my own life once i discoverd the preload on the damnd thing)

This is definitely not the correct way to do this, mind that they had 6cm of preload.

But i managed to get a good look at the inside workings of the damper. 

I decided to limit the inner-dampers stroke by 15mm. Thus shortening the Eye to eye measurement to fit my bike.  In order to make it work i added a top out blocker, an additional insert of 15mm to keep it all working in the same housing.

Comparing one of the shortened dampers to the un-modified one, i also modified the mounting bushings to fit to the original pins welded to the frame.

Checking the initial mounting, it fits!

After a lot of calculation, i cut the koni springs. This increases there rating thus lowers the amount of preload needed. Unfortunately i fucked up a little. and forgot to take in to account that i needed to lay down one winding and grind it flat to fit the washer. I ended up with the correct dynamic and static sag on the highest preload spring setting. Not what i wanted but still functional.

Fitted to the bike it looks period correct, and the adjustable damping knob and adjustable preload just makes it that more racy. The chrome damper and spring keep the classic look going. Im so happy with this end result.

Sorting the front end

In order to upgrade the braking and have a correct working front fork i browsed for different fork options. The easy thing to do would be to fit CBR400 or R6 front-legs with there triple clamps and brakes. This would instantly put the bike in to this millennium, suspension and brake wise. But it would look "off" i wanted to keep it period correct, so i opted to upgrade the original front end.

The very first purchase i made for this project was buying a second hand fork with all the chrome left on the inner tubes. I was in luck with those forks as they could fit double sided brake disks (and calipers). During my parts scavenge i looked in to several possibility to make fit an larger diameter brake disk with a different caliper. The double brake disks was a popular conversion back in the day (may be still is) but i  like the more original look of a single disk.

On a swap meet i found a Moto Guzzi (brembo P8) Caliper and 320mm Disk (1100sport?) this disk had the correct mounting holes and aligning bore for my hub. So in theory i only needed to space the caliper and it would all line up. But adding an adapter is'nt that nice looking and would look "off" so i went the difficult route (again). I decided to have a couple of mounting lugs welded to the lower leg, since i had a pair of lower legs "extra". The brake disk needed to be spaces outwards so the caliper could clear the spokes.

At first, i made a quick and dirty spacer to mock-up brake disk position.

Then i Eye-balled the calipers location.

Point of no return cutting of the caliper mounts from the lower fork leg.

I made fit 2 new lugs on the backside of the fork-leg. While braking the welds are mostly subjected to bending forces and pressure. which is easier to handle.

Lowerleg in the welding mould, with a worn inner tube slid inthere to prevent weld distortion of the sliding bearings of the fork leg.

The polished and welded bottom leg, shiny

To compensate for distortion i made a new set of wheel spacers and brake-disk adapter.

All bolted up and ready to go!

This caliper needed a new master cylinder an brake hose to! So i looked in the parts heap of my-dad and found an 11mm master cylinder of a Les mans, this was serviced with a seal kit from a ducati rear master cylinder but hey it works.

The overhauled master cylinder piston and its guide, ready to go in!

The assembled brake system and new inner tubes of the fork during shake-down testing. POAH did this brake work and how does upgraded suspension increase the rideing fun. Touching the brake was like riding in to a wall, the feel in the lever is splendid, i used black colored braided hose. 

This was a mission accomplished for me, upgrading brakes and suspension but keeping the classic period look of the bike!

i still want to visit SO-products and get my suspension dailed-in some more, i really want to slide in cartridge emulators for the front fork to upgrade its damping. I first need to save-up the funds for that.

Up next is the performance upgrades, which interfered  the rear brake functioning.

Continue to next post.