Skrunkwerks R90 Scrambler
Swap utility for speed, road for the salt, this build is the opposite bookend to the Skrunkwerks salt racer. From the outset, focus was on practicality, comfort and performance. In short, a long-legged mile muncher that wont loose its lolli when the bitumen runs out. Plus some more ooomph than the stock R90. The large slab sided tank of the R90/6 spells Teutonic classic and is a solid model to form the basis of a build. But it can stand improvement in a number of area’s, these became the heart of the build’s mission.
- Bike:1974 R90/6
- The very ordinary stock ATE brakes and disk are replaced with a 4 pot Brembo (from a GSXR 750) and 330mm ECB rotor (for a Ducati 1198). Brake lever is a Magura HC-1 (15mm). Adaptors and spacers to accommodate this upgrade were supplied by R90X Big Brakes
- Renthal FatBars with compact Ducati switchblock. All wiring hidden in bars. Daytona Speedo. After market headlight bucket. All wiring replaced with aid of Motogadget m-unit. Kellermann LED bar end indicators.
- Stock tank with custom paint and kneepads of Tasmanian Tiger Myrtle by a maker of fine stringed instruments, Tim of http://timkillcustom.com/
- Engine: Completely rebuilt from bare case including increase to 1000cc. Heads machined by Skrunkwerks to suit 1000c Siebenrock ‘re-power kit’ to avoid the stepped pistons of their ‘power kit’ for the R90. Head machining included a further compression ratio increase to 10:1. More info here.
- Fitted with a Skrunkwerks dual pattern performance cam. More info here. Intake valve diameter increased to 44mm. Ported using in-house flowbench. 38mm Dellorto PHM carbs with velocity stacks for correct tuned length hidden under large K&N pod filters. Mufflers are DanMoto items (NLA I believe).
- Stock airbox replaced with a Skrunkwerks carbon fibre rear engine cover.
- Tractor sized stock flywheel replaced with the much lighter ‘clutch carrier’ of later models which also allowed the fitment of the much improved gearbox from a 1987 R100. Shifts are far less clunky.
- Custom seat and subframe with luggage rack and brackets for Legend Gear saddle bags by SW Motech Germany. Of the many modifications, the sub-frame/rack took the longest. Cutouts were milled manually..
- Kellermann all-in-one LED rear lights and bar end indicators.
- Ikon rear shocks (15mm more height at rear).
- Powder coated wheel rims with SS spokes and shod with Heidenau K60′
It’s a fun ride.
Also see Pipeburn post here: https://www.pipeburn.com/the-whole-werks-bmw-r90-scrambler-by-skrunkwerks/