Frame Build Part Three

A very British motorbike

Now the bike is beginning to take shape. After weeks of planning and measuring, Tigcraft get down to the business of construction.

Enigma 1050 frame tacked up side view
With the engine in the jig, Tigcraft’s first task was to shape the tubes for the front end of the chassis and then tack weld them into place.
The engine is used as a stressed member of the chassis. The approach we are taking is not unlike Ducati’s 2011 GP bike although we are using tube not carbon fibre.
Once all the tubes have been tack welded into place, minute adjustments can be made if required before the welds are completed.
Front three quarter view of Enigma 1050 frame
Enigma 1050 front subframe rear three quarterOnce he was satisfied that everything was correctly aligned, Dave Pearce welded the front subframe together. Note the extensive use of triangulation which maximises the strength of the structure and spreads the stresses out evenly. The rear three quarter view (above) shows how much effort is being made to keep the frame as slim as possible.
engigma 1050 front subframe side view
CAD drawing of Enigma 1050 swing arm plates
Enigma 1050 swingarm plates made by Promach
Meanwhile, up in Leicestershire, Mick Edwards at Promach was drawing up the swingarm mounting plates on his CAD program. He worked from metal templates which Dave Pearce had supplied.
The CAD program is supplied by Hurco, the manufacturer of the CNC (Computer Numerically Controlled) milling machine on which the plates were made. Once the drawings have been completed and checked, an automatic routine translates them into program code which is fed into the milling machine.
Enigma is being built all over the country. Once Mick finished the plates he posted them off to Dave in Hampshire ready for fitting to the rear of the engine.
Dave Pearce attaches the plates to Enigma 1050Dave Pearce bolts the swingarm mounting plates to the rear of the engine. The rear engine mounts on the 1050 engine are massive and will be able to cope with the stresses created by the rear suspension.
Enigma 1050 chassis showing swing arm platesYou get a better idea of the size of the plates when viewed from this angle. Note the function of the dummy swingarm spindle in the jig. Mounting holes for the rear subframe and footpeg hangers are already in place.
Enigma 1050 chassis showing fore and aft tubesTigcraft’s final task for this stage of the build was to add the tubes which connect the front subframe to the swingarm mounting plates. We are now ready to start thinking about the fabrication of the swingarm.

That’s the main chassis taken care of. Dave has almost finished the swingarm now. See it here.

Enigma 1050 – a very British motorcycle being built in Hampshire, Derbyshire, Leicestershire, Berkshire, Wiltshire, Surrey, Sussex, Suffolk, Shropshire and Cambridgeshire.