Mounting oil temperature and pressure gauges

The pressure and temperature gauge story so far: sensors installed, having sorted out the position of the oil pressure sensor so it wouldn't foul on the exhaust,  wiring harnesses made up to my satisfaction. Time to think through mounting the gauges themselves. The instruments on the mark 1 Trophy are mounted in a binnacle that bolts to the underside of the forks' top yoke. They are offset from the yoke and a bit of measuring suggested there would be room enough to squeeze in the the little gauges I'd bought.  

So the next question was how to mount them. With a bit more measuring, I could see an additional bracket would be possible to replace the bracketry they were initially fitted with. This new bracket would share the two M6 bolts that hold the main instruments in place. I'd already improved the firmness with which the main instruments are held in place so I was pretty confident about the security of this plan. I marked out my design on a bit of cardboard and cut it out to see if the idea would work in the space. 

The gauges came with a swivel mount attached to the front edge of their aluminium bodies. The only trouble with my plan was that the gauges would have to mount upside down because I'd need to attach them at the back of their bodies rather than the front. So I would have to reverse the guts of the gauges so my replacement bracket would screw to the rear edge instead, to solve the problem of the digits being upside down.

 So, idea demonstrated as feasible, I marked out the shape and holes I wanted on a 1mm aluminium sheet. I drilled the holes out before cutting with my jigsaw because it is much easier to drill into flat sheet than the something with bends in it. I decided to drill two possible mounting holes for the gauges so I could choose between two heights.

With the shape cut out, I clamped it in my pretend workmate and banged over the extensions for the gauges with a rubber faced mallet, then tidied up the roughness left by the jigsaw and drill with a my favourite fits.

 A trial fit showed the bracket was marginally too wide and the top edges of the gauges needed to move inwards and rearwards by between 5mm and 10mm to avoid fouling the top yoke and instrument binnacle.

I put a little bend into the aluminium to bring the gauges away from the binnacle (visible) and then another bend just inboard of the 90 degree bend to tilt the gauges inward towards the centre line of the bike (not visible).

I was now happy with the positioning of the gauges so needed to sort out the fact that they were upside down. I was also concerned that these car gauges might suffer in the rain. The electronics for the gauges are mounted on a small circuit board so they are on the opposite side of the mounting screw. Reversing this circuit board ran the risk of the mounting screw contacting the components. I solved this by cutting a piece of plastic sheet (actually the blister from the box the gauges came in) to insulate the electronics from the mounting screw. It was a bit of a fiddle to get it back in reversed with the improvised insulator but I got there with both gauges.

 I bought a box of o-rings in various sizes at an autojumble. I found some rings that were the same external diameter as the gauge bodies and coated them in rubber grease to help keep the water out. I gave my new bracket and the gauge bodies a coat of paint too.

 Here they are in place. I'm not sure about the purple anodisation. Purple and red aren't a great combination so I'll probably get the Smoothrite out again. Still, pretty neat, eh? They might even work ... ;-)