Sunday, January 27, 2013

Some inspiration

Warmer weather this weekend; while I did a bit of work on the ex650, I spent some time working on a wiring diagram for the Cafe Racer.  My first attempt was close, but even better solicited some sympathetic support from, and someone did up a really nice one for me, all computer generated and color coded.  The kids and I will start the wiring process shortly.  Follow the progress at

On the ex, I simply mounted the rain tire on the black front wheel (sold the red one to Wilson, who has gone the way of the diesel after selling his TZ250), and got the bike off the front stand.  Still waiting on some rotor spacers for the Carrozzeria wheel, but at least the back-ordered wrist pin has arrived.  So my new OEM piston set is complete, and according to Canada Post, my Cylinder head has arrived at RLR in the UK.  Should hear from Rick shortly as to progress on that build.  I also have come to understand that RLR has a Isle of Man-winning pedigree, winning two races with a certain John McGuinness on an RVF400.

As usual, my head is full of ideas on how to improve the racebike.  I've gotten some inspiration from a supertwin racer posted on eBay UK.  I even was able to ask some questions of the seller...

The first photo looks pretty typical, in that it has an aftermarket front fork, ZX6 bodywork (however with the ram air in the nose filled in), and what looks to be a cbr600 tail section.  However, what are those 4 holes doing in the leading edge of the fairing...?

What you can better see from this angle is the side mounted radiators!  The owner used the radiators from an RC51 (hmmm, I had one of those!), and some serious plumbing work to get them to work properly.  Of course, removing the rad from the front allows a gaping ram/cold air intake in the front -- unfortunately no detail pics on that were available.

The other side has the matching half from the Honda.  The rads themselves have a fitting for a water temp gauge.  Note the rearset plates look an awful lot like my homemade jobbies pre-woodcraft.  No shift lever?  The owner lost his left leg, and has to use a right hand shift -- not the rod extending up from the shift spline, to carry over to the right hand side of the bike.  Genius!

The other bit of ingenuity is the aluminum subframe.

In the long term I envision an aluminum monocoque subframe/seat, sorta like what the GP have in carbon fibre.  I would use aluminum sheet rather than the tubing shown here, and have an fibreglass "pod" attached to the rear for aerodynamics.

Here is a sketch I came up with awhile ago.  This would also necessitate a custom fuel tank  -- in order to remove as much rear subframe as possible, and to move the ECU forward.  A faux fuel tank cover would be made to replicate the shape of the original, and hide the smaller tank which could be mounted to the main frame rails.  The seat pan would then attach to the top of the frame, as well as utilize the mounts for the rearsets.  This could potentially be bent into the right shape, but I think I would need 1/8" aluminum sheet, so perhaps cutting out via templates and welding is a better option.  The battery could be mounted on the inside of the subframe as above, with the undertail being bolted into place, adding some rigidity to the structure.  The fuse box and powercommander would also fit easily in the space provided.

With this solution, the tank is mounted to the main frame, not the subframe.  The ECU is moved forward for easy access, and the weight transfer of 2 gals of fuel sloshing forward in the space for 4 gallons would be eliminated -- centralizing the mass.  A foam seat pad would be attached to the aluminum subframe itself; the "pod" of the tail would be bolted to the back of the seat (like the Aprilia RS250).  In the event of a crash, the fibreglass pod would bear the brunt of the damage, and could be easily replaced.

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