Entries by adrian

airhead salt racer gets stiffed!

There’s a certain satisfaction in hacking tons of detritus and redundant bits off a frame – a bare canvas on which to plonk your own detritus and redundant bits! Effectionally known as the ‘rubber cow’ the airhead frame is well known for it’s elastic nature.  BMW, in their wisdom, took the lengendary Norton Featherbed concept […]

dyno deck

The deck frame is made from 40x40x3 angle and 40×3 box tube and the deck itself is 5mm aluminimum chequerplate. The legs can be bolted to the floor.

dyno frame – the module

he frame for the roller module gets a look-in now. The frame is made from 75x75x6 box section and will be eventually bolted to the floor. A bracket for the brake calliper was fabricated and the pillow block bearings are standard 60mm UC212 units. The deck is 5mm aluminium chequerplate. The bearings are induction heated […]

dyno roller – in the groove

ow that the shaft has been shrunk into the roller, the assembly goes into a CNC lathe to take a lick off the O.D. and to machine cross grooves using the live tooling of the machine. Not many dyno rollers have this feature (usually heavy knurl instead) and I’m exceedingly lucky to have access to […]

Big lump ‘o’ steel

he dyno roller starts off with a raw hunk of K1045 steel, 460mm in diameter and weighing 400kg. Some people turn down each end to form stub axles, but in my case, the shaft is quite long so this is not feasible.  Instead, the shaft will be made separately and shrunk into the lump.   […]

The dyno roller

The lump has a polar moment of inertia of 10.07 m^2 kg. So your average airhead should produce a run of around 10 seconds in 4th gear. If  successful at getting around 90hp at the back wheel of the salt racer then runs will need to be done in top gear. In which case, that […]

dyno – exploded view

ere’s an exploded view of the dyno design. The main wheel has been sized to suit the types of bikes that I will be testing: bikes from the 70’s and 80’s, mainly airheads. The red wheels are removeable and  can be installed to cater for bikes with more horsepower. A disk brake is incorporated to […]

luftkopf No. 1 – BMW Cafe Racer

Cafe’d 1981 R100RS: Custom werk by skrunkwerks: Carbon fibre filter filler and rear wheel hugger  :  Rear tail piece  :  Custom bracketry to lower S-fairing  :  Rearsets  :  Clip-ons  :  Triple clamp  :  Mufflers  :  Paint job  :  Dual plugging  : Head porting Other bits: 336 BMW Sports Cam :  38mm Dellorto carbs  :  Koni […]

measuring compression ratio – method 1

ncreasing the compression ratio of luftkopf #1 is long overdue. Aside from being one of the easiest ways of adding horses, the BMW 336 cam wants it badly. The valve pockets in the piston domes have been deepened to accommodate the higher lift of the cam and I have often wondered what difference this would […]