Thank you MetroMPG and VARN
Here you can see the speedometer:
The holes had fairing speakers. the plastic was marred in a few weeks .
I had thought to put the classic vacuum gauge 2 "( 52mm ) , like these :
52mm Calibrador Puntero medidor tabla Mesa vacío Leer de 0-30 in.Hg Vacuum Gauge | eBay
Tim Vacuum Black Dial Face Mechanical Analogue Dash Board 52mm Gauge | eBay
I have also seen these electronic gauges 2.5 " (60mm )
negro cara 2014.01 60mm calibre coche vacío, luz blanca, auto manómetro de vacío, metros del coche, barra 1.0/ap106 en Instrumentos de Motor en AliExpress.com | Alibaba Group
60mm defi avanzada serie cr calibre coche vacuómetro metro de auto negro cara en Instrumentos de Motor en AliExpress.com | Alibaba Group
The problem is that there is no space . They are great to put on the fairing .
I thought to put the vacuum gauge on the handlebars or .
Add a dome to the fairing and put the vacuum gauge on the dome . the dome is like this or another model: