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EXUP (Exhaust Ultimate Powervalve)

Whats it all about?

Yamaha was the first to develop such a system in the late 1980's, called the Exhaust Ultimate Power Valve (EXUP). The valve is fitted to four-stroke exhausts and constantly adjusts the internal diameter of the exhaust system by way of a rotating blade across the collector box. This "tunes" the exhaust to better suit engine sppeds; thus creating more low down torque than a conventional exhaust. The valve is moved by a servo controlling a push and pull cable system that's linked to the bikes CDI unit.

What does it look like?

Click to enlarge image
 
GSXR1000 forks

Let's start at the front. The forks are gold nitrided GSXR1000 units, with full Ohlins internals.

The front wheel is a carbon-fibre Dymag with a one-off stainless steel spindle, machined by Kevin Bartlett of POD Manufacturing. POD was set up in 2005 by Kevin and his business partner Paul Debling, and specialises in motorcycle parts as well as precision engineering for the pharmaceutical and aerospace industries.

The front brake calipers are Tokico six-pots from a Suzuki GSXR1000 K1.

 

Headstock

The forks are married to an LSL straight bar conversion. LSL are a German company specialising in aftermarket bars for sports and touring machines, as well as rearsets, steering dampers and other accessories.

Don't worry if you don't speak German, you can find a range of their products in English at Motorcycle Road & Race.

Frame by Steelheart Engineering

The frame was custom-built by Lee at Steelheart Engineering in Canterbury back in 1997 and originally housed an 1990 FZR 1000 motor with billet clutch, Stage 3 Dynojet kit, Dyno coils and the usual tuning bits you would expect to find on an Exup.

It was a great fun bike to ride as you can imagine and was the genesis (groan!) of the project as you see it today.

Frame from above The steel frame has been powder-coated by ?????? for corrosion protection and appearance - I'm still not sure what the bike's final colour scheme will be nor what sort of clothes she's going to wear!
Frame from the rear The rear end is shod with 200-section rubber on a magnesium Dymag wheel, painted carbon-effect by an artist in the USA. I'm running a 37-tooth rear sprocket, purchased to suit the wheel. The rear brake caliper is a Brembo unit, and the tyre size is 200/50/17.
From the swingarm pivot, looking back Looking back from the swingarm pivot, you can see the Ohlins shock. The shock is a fully-adjustable YZF750SP unit (for more info see below).
YZF swingarm is just temporary

The YZF750SP swingarm will be replaced by a custom-built one eventually. The swinging arm spindle is another stainless one-off by Kevin at POD Manufacturing. You'll find his handiwork elsewhere on the bike as the build progresses.

You can see the compression damping adjuster mounted to a custom bracket on the frame.

Rear suspension by Ohlins

The Ohlins shock features a remote reservoir (where would bikers be without cable-ties?) and hose-mounted hydraulic spring preload adjuster. It is fully adjustable for length, compression and rebound.

That black hose you can see leads from the shock body to the preload adjuster on the other side of the frame, which you can see better in the picture above.

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