Il Castrolo x 940


1999, 750 Ducati Monster

Well, this could be a long one! About three years before Tom and I started Foundry, so 5 around years ago, after seeing a picture of a great stripped down SR500, I suddenly had a fancy to build a custom bike. I’d not done much before except tinker with pushbikes and I’d always been into designing and making stuff, mainly furniture. I then took forever to restore an XT500 to average condition, but the bug had bitten..

After looking for about a year and missing several SR’s and XT’s, I realised that instead of paying good money for a donor, my old Ducati 750 Monster was sitting in the corner of the studio. My first ‘proper’ bike, it had been superseded by an R1200R BMW, but I hadn’t the heart to part with it.


Il Castrolo x 940


Off came the seat, thinking that I’d just re model the back end with a new seat unit and call it ‘flat tracker’. After a few sketches, some Photoshop sessions and innumerable mock up’s I realized it was a bit trickier than I’d assumed. There was also the fear factor. Novice builders usually go one of two ways, either mad with the grinder and end up screwing the first project or, being worried by anything more abrasive than a nail file, for fear of screwing things (sound familiar?)! I was in the latter class. As a product designer, the concept of chopping up a perfect, good looking well maintained piece of Italian automotion was a bit bonkers. The little devil with the howling grinder was sitting on my shoulder revving the hell out of it, but the pause button was pressed.

Fast forward a year and, having moved from London to Sussex and transported the ‘paused’ project to a tiny, freezing lock up, the itch needed scratching again. I’d bought a welding set (and could gas weld passably), but to weld, you need to cut! Not owning a grinder, the trusty hacksaw came into play and I’m sitting looking at a once good Monster, minus about 12 inches of the frame. It had become patently obvious that the stock monster has so much character in the tank and frame; it’s hard to give it a new look without getting heavy handed. Any idea of ‘returning to original’ was abandoned and the tank discarded. Getting that nice horizontal line along the bottom of the tank and seat was going to be a challenge with the sloping frame, but out came the filler and sanding blocks and the new panels took shape.


Il Castrolo 2 x 940


I wanted to keep the overall look ‘light and minimal’, just get the balance right and the general flat track image, using a separate tank and seat. I’d just finished the basic mouldings when ‘shock horror’ I came across sketches of another Monster Tracker! The Alex Earle bike took a different s approach to mine. I’d built a sub-frame to carry the seat and back edge of the tank; Alex was showing a one-piece monocoque unit. Shortly after the sketches he showed a small-scale model and then the final bike. It’s a great looking machine but a bigger, more ‘hard core’ beast altogether and I still wanted to keep the light nimble look.

Along came Foundry and Tom and I decided to pitch in and start building bikes full time. First setting up the workshop and then project after project came along and the Duke was pushed further under the bench. After finishing The Pipeline our ‘stainless’ Moto Guzzi, we were expecting a couple of big projects that didn’t materialize, so it was Monster time again. We hand cut all the sections of the two into one exhaust, Tom stitched it all together and we turned up our own end can. We’d already hand cut the footrest hangers (no CNC this time!) to take Tarrozzi controls in standard Ducati positions. The frame was de lugged and all the fixings for the seat sub frame welded in place. We also added a couple of rows of internal loops for the wiring harness to loose the dozens of zip ties that Ducati love!

At the front, the Ducati headlamp and dials have been replaced with a 4 inch Simpson Detour light, set into the rolled ally number board and a Koso digital ‘clock’ which has speedo, revs, and all the warning lights in one unit. It was going to be old school analogue, but the Koso is a really neat unit and gives the bike a modern twist. To give the bike full ‘roadability’, it’s wearing some neat little LED indicators, which are D-Light by Daytona. The wider and taller Renthal bars needed new Hel brake lines in a tasty red.


Il Castrolo x 940


With all the structural work done, the bike was stripped and recorded for our first Foundry movie ‘The Dry Build’ (, then blasted and powder coated. All the frame bearings have been done and Tom completely stripped and re-built the top end of the engine.
Colours are always a dilemma on ‘home’ projects! First off, it was to be a wild multi coloured splatter finish tank with a bright frame, but the ‘Iodine’ metallic grey worked so well on the Pipeline, we went for that on all the frame parts and wheels and a chance glimpse of Mike Hailwood’s 1978 TT wining bike inspired the design for the paint scheme, nicely implemented by Stuart at Jago Design. It shouts ‘Il Tricolore’ the Italian flag, but was originally cribbed from a Castrol oil can! To give it a slightly bling ‘race bike’ look, The Trimming Centre, did a great job on the Red, Green and Cream seat. The engine was stripped externally and painted silver to give an old school ‘all alloy’ look and simplify the shape of the motor.
Under the tank, a pair of K&N’s replace the massive air box, feeding the overhauled carbs and, an ally tray now carries all the electrical hardware which has been re-wired into stock hand controls. A lightweight Shorai battery now sits forward of the engine within the frame.


Il Castrolo x 940


We always wanted to move the air cooler as it’s so imposing on the 750 Monster, especially with the long braided hoses and ‘carb de-icing’ pipes complicating things. We blanked off the de-icing gear (as I’d never needed it!), built a new oil cooler and slung it low under the engine with the shortest of pipe-work. A lot tidier and it give more of an air cooled look to the bike!
Tyres were a bit of a challenge. The ideal Maxis with the classic flat track pattern aren’t available with a 17 inch front and a lot of the other small chunky treads don’t come in a 160 for the rear. Avon Distanzia’s were in the correct sizes but a bit chunky, so we settled on Pirelli Scorpion MT60 Corsa. The slightly taller 70 section front gives a bit more bulk to the front end and sit’s the bike up a little, which helps the stance. Apparently it’s a track biased sticky compound with lots of grooves, so should be a pretty grippy ride! The last fabrication was the front mudguard frame, to give a nice snug fit over the tyre with the shortened fender.
In terms of problems, custom Duc’s aren’t easy to work with. They’ve got so much character in the frame, it’s hard to stamp you own look on the bike. And, with everything inside the trellis, it’s a like working with all the parts of the bike in a cage. The exhaust is a real challenge! One of the key ingredients to the look of the bike is the short section of tube at the back of the tank, which is actually part of the seat sub-frame. It makes the new components look like they are all integrated with the frame and in retrospect, we’d have welded this directly to the frame.
We hope you like ‘Il Castrolo’. We’ve got the moulds for the tank and seat, so we just need your old Monster to crack on with the next one.
Si and Tom.

The bike is for sale, so for further information, contact Simon or Tom on +44 (0) 1243 532 888 or