BMW R100RT Tracker by Marmisto

BMW R100RT Tracker

Chris Daniels of Dorset, UK, has an extremely interesting background. Besides building custom bikes, Chris is a conservator, carver, and author of two books on stonemasonry and restoration. Having trained in Venice, he’s carried out work on everything from microscopic examination of materials to full restoration of buildings of major historical importance across the world.

BMW R100RT Tracker

What’s more, Chris has been shed-building bikes since the age of twelve. Being into conservation, he loves to recycle and re-use parts — something we love. He’s actually writing a commissioned book at the moment on shed-building custom bikes at the moment (we can’t wait!), and he’s going full-time as a bike builder.

Given this background, it should come as no surprise that his bike-building shop is called Marmisto, which means “Stonemason” in Italian.  While most of us find a great deal of peace in our shops, sheds, and garages, we hardly think of them as comfortable. But for Chris, who is used to working with ancient stone, the shop is a luxury:

It’s warm in my shop, not in old buildings, and I’m fed up with dust…

Today, we’re featuring his BMW R100 RT tracker build, which is loaded with a wide array of recycled parts, including everything from a rear light housing from a WWII mortar shell to a statnav mounted in a fire extinguisher body! Full details from Chris below!

BMW R100RT Tracker:  In the Builder’s Words

BMW R100RT Tracker

(Words by Chris Daniels. Highlights by us.)

R100RT:  started life as neglected hack, stripped down and everything redone. As you’ll see from my website, I’m a conservator, carver, and author (writing a commissioned book on shed-building custom bikes at the moment) into conservation, which makes me love to re-use, so this baby has a lot of recycled parts, adapted to become part of the bike. These include:

Harley front hub machined 10mm wider than standard to take wider tyre on ex-Bombardier competition rim with stainless spokes (suffice to say, if it ain’t aircraft alloy, then it’s stainless on the bike). Shaved forks sit in my design yokes and fork brace, with progressive springing and revised damping pattern.

BMW R100RT Tracker

Frame was de-tabbed, cleaned and XT500 rear frame grafted on, then powder coated; swing arm modded to take wider tyre that sits on another Bombardier rim with a reworked GS100 hub, modded to take normal spokes by inserting bored, stainless button head bolts into tapped nipple wells. The hubcap was turned from a bench grinder housing and has a 50’s Studebaker horn button cover as a finishing tweak.

BMW R100RT Tracker

Motor is fairly standard at the moment, apart from being cleaned up and assembled well, as it’s my first Beemer and I want to assess and tune as I go. Carbs are flowed and pull air from a modified fruit hopper off an industrial juicer, while the big bore pipes in the photos were made from ex milking parlour 316 stainless tube and GT performance mufflers. (I’ve had a new set made with slightly curvier shape, but shall save them for the buyer rather than leaving these ‘originals’ on when they’re blued up). As it’s approx 60Kg lighter than standard it should tootle along nicely…

  • Bespoke oil cooler system, with aircraft hosing.
  • Mudguards cut from a rear alloy fender of an old Brit trials iron with welded on brackets.
  • Controls are all s/s machined with phosphor bronze bushes and bespoke pegs.
  • Handlebars are modded Easton Ultrafats with all wiring inside from revamped 70’s Yamaha and Kawasaki switch gear. No speedo, instead a Blaupunkt satnav (they were the only manufacturers of a round one, and only for a couple of years) that sits in housing made from a fire extinguisher body, having a jack direct to helmet earphones.
  • Tank/ seat is a TT500 alloy tank extended into a single unit, with my (first) attempt at aluminium bodywork.
  • The grafted in rear light housing is turned from an ex WW2 mortar shell with a VW camper lens and LED lights. Seat is handmade and leathered to fit by an upholsterer colleague.
  • Battery is boxed under the gearbox and all wiring tucked away — but not too much — I’ve learnt my lessons with complicated design. This bike’s simplified and easy to work on.
BMW R100RT Tracker
Mortar Shell + VW Lens!

I carry out all the design and the majority of work in-house, using the services of a specialist aerospace welder and competition motorcycle machine shop for the twiddly bits. And I did the paint as well.

BMW R100RT Tracker
Modified Juicer Intake!

Follow the Builder

Follow Chris Daniels:  Web | Facebook








  1. Ha! Proof that you can build a custom with fenders, and they look great.

    Very cool bike.

  2. wow! one of the best designs I see….

  3. Steve Phillips

    Not generally a fan of BMW customs,! But this one I like, the blend of parts works so well and I’m a big fan of making your own custom parts,, to me that’s the essence of ‘custom’
    Very nice ?

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