Banish Buffeting

No, this is not a blog about the memorable cinematic misrepesentation of who made a sonic boom first as depicted in The Sound Barrier, but rather it describes an attempt to improve the sound quality of my BMW R1200GS motorcycle whilst sitting behind the screen.

This bike already had the Advenure screen and winglets fitted when I purchased it.  This provides some protection from wind blast but I hear quite a lot of noise spilling over the top of the screen - it is evident that if I lower my head a fraction this reduces substantially. The noise is produced by turbulent air flow - essentailly little eddies of air that are unstable.

I fitted a Wunderlich wind deflector - this does not really work and is fiddly to adjust - it is simply to narrow.

I have now fitted a GIVI Air Flow screen - this additional top screen (part number AF49) sits on top of the existing screen and its scoop should direct air at upwards and in a more stable flow over the rider's head. This promises to produce a quieter ride through reduced turbulence.  It is possible to fit a complete GIVI Air Flow screen but this would have involved additional work in moving my GPS mounting (and expense!).

This is how I fitted it:

The GIVI mounting blocks need to be attached to the existing screen - here I am holding the AirFlow in position and marking out the positions for drilling.  I used a paper template too.

Each mounting block requires a 20mm and 2off 4mm holes.  Here i'm using a standard wood drill bit  runa t slow speed to avoid melting the acrylic. I drilled 22mm holes to allow for positiong errors.

Mounting block in place - one each side. The lever latch operates a cam arrangement that engage with an external block - this grips onto the moulded in runners on the Air Flow screen and locks it in place and allows easy re-positioning.

The mounting block viewed from the front. This needs to be finally tightened with the Air Flow in situ so as to adjust the friction on the screen runner.  A thin 10mm spanner does the job.

Air Flow in low position - it slides up and down when both latches have been released (even on the move).  It can also be removed entirely.

Air Flow in high position

This is the Wunderlich flap - I arranged for the Air Flow low position to be the same height as this.

Principle of adjustment

Parts list:

Givi Airflow AF49 Replacement Sliding Screen Part (Z1997R)

Givi Z1963R Spare Replacement Latch Kit as used on e.g.Airflow Screens AF330

 

The Useless BMW Vario Top Box - the Revenge

BMW sell a vario top box made by Shad.  It incorporates a mechanism for changing its size but at maximum volume the box is not large enough to take a modern full face helmet as previously reported..  The mechanism is not well designed from a mechanical standpoint and jams easily.

I have therefore removed 1 kg of useless gubbins and bolted the box together in its maximum size configuration.

The vario mechanism - a real bind at the best of times.  The box has a sliding top hat incororating the lid assembly and a rubber seal

Over complicated and mechanically dubious in action - this little lot adds almost 1kg of weight and wastes space

With vario mechanism removed and the box bolted together more volume is available (although only  a little extra height is gained).  I could trim the screws I suppose.  The lid cords are attached to the rear most boss using ring crimps (not shown here).

I used dome headed 4mm stainless fasteners  - looks reasonably neat.

Shower Improvements

What to do with a strong mains pressure cold water feed and a weak gravity fed hot supply?

A pressure regulating valve maintains 3 bar pressure for the cold feed and a pump boosts the hot supply by 2 bar or so.

Works a treat now!