Research / The front end: USD forks, colour, triple clamps and the dash

OpenDecision D44 Front end, wheels, brakesUpdated

The front end: USD forks, colour, triple clamps and the dash

Line drawing of the CX500E front wheel, forks and engine, with axle dimensions
The front end as it is now: the stock forks and 18-inch wheel the USD conversion replaces.

Decided

The order of work:

  1. Check the donor forks on a road trip.
  2. New triple clamps, with the digital dash set into the top clamp.
  3. Calipers.
  4. Bars.

The finishes: gunmetal grey calipers front and rear, matched, with braided lines and gold ends for a fleck of colour. The calipers get cleaned and coated rather than replaced. Powder coat or Cerakote both work on cast bodies; anodising doesn’t.

The bars: clip-ons that clamp under the top clamp and rise to finish flush with it. On USD forks the clip-ons clamp the outer tube (about 50–54 mm), not the 41 or 43 mm stanchion. The build manual got that wrong.

Open: which donor fork

The colour target is gold, with red as the fallback.

Option Why Catch
GSX-R1000 2001–02 or 2009–11 Gold from the factory; Cognito sells GSX-R stems for CX/GL frames Need to find one
CBR1000RR 2007 Gold Showa forks; keeps it all-Honda; off-the-shelf stem Need to find one
R1 2004–06 Offered by the wrecker 43 mm Kayaba; colour not confirmed
Any donor, re-anodised red Works on forged parts once the steel is out Cast clamps go blotchy
Ducati 1198S Looks the part No off-the-shelf stem, custom trees, no CX build has done it. Last

The 2007 R1 I found on 21 Oct had gold KYB forks, gold radial calipers and aftermarket wavy discs. It sold before I could get a price.

Open: clamps

Two routes, and I haven’t chosen:

  • Machined clamps for the donor forks, with the dash pocket. This fits the “dash in the clamp” idea, but I haven’t found an Auckland machinist yet.
  • A Cognito conversion stem pressed into the donor’s lower clamp, with All Balls 99-3541-5 and 99-3512-5 tapered bearings.

No Cognito listing names the CX500E. Its frame belongs to the GL500/GL650/CX650E triple-backbone family, and the bearings are the same across all four Cognito frame listings, so stem length and thread position are the real variables. I measure my stem and send Cognito the numbers before ordering anything.

What would change it

  • The measured stem, head tube and stock fork length (a GSX-R fork is about 75–100 mm shorter than the CX/GL forks the library could find).
  • The caliper mount spacing on whatever donor I buy. The library has 108 mm on comparable bikes, not the 100 mm that was assumed. Measure it before buying aftermarket calipers.
  • The LVV certifier. A fork, clamp or stem change isn’t on the WoF exemption list, so it’s part of the LVV job.

History

  1. The 2007 R1 had sold. The wrecker offered a 2004–06 R1 instead; colour and condition to confirm.
  2. Set the order of work (forks, then clamps with the dash, then calipers, then bars) and the finishes: gunmetal grey calipers front and rear, braided lines with gold ends.
  3. Found a blue 2007 Yamaha R1 with gold forks at a wrecker.
  4. Library: a GSX-R or CBR USD front end on a Cognito stem with All Balls tapered bearings is the off-the-shelf route. A Ducati 1198S has no off-the-shelf stem and ranks last.

Sources

Spotted something wrong? Tell me. Jeff Sutton is building this, not an expert writing it up.