Picture of How to install a tachometer
In this instructable I will show you how I installed an aftermarket tachometer on my ‘91 Chevy S-10. Tachometers are a great tool for your vehicle if you enjoy monitoring your engine speed or idle. In fact, they are nearly a necessity for a vehicle with a manual transmission. 

Step 1: Parts & Tools

Picture of Parts & Tools
Tachometer - - - - - Can be purchased from most any auto parts store for as low as $33. Mine was salvaged from my old truck
3M quick splice connectors 14-18 gauge - - - - - $4.10 (Walmart)

Wire cutters
Wire strippers
Automotive diagnostic tool-used for finding tachometer wire 
Ratchet and sockets

Uday nani13 days ago
Hai i brought a speedometer from kinetic gf 125 bike, i want to install it to my bajaj bike it has 4 wires orange, black, white and yellow plz any body tell me how to connect the wires

i dont think anyone has mentioned it yet... you should have put a grommet in the hole where cable goes through the firewall.......doubt you would start a fire tho, like some muppet suggested

rey_salasjr9 months ago

what about diesel engine?

mikaleda2 years ago
You need to install a rubber grommet where the wire goes through the firewall so it doesn't cause a short. The way you are running it is dangerous it could start a fire if the wire were to short out.
Harvard822 years ago
You really should add a grommet between the wire and the firewall or else vibrations will cause the firewall to cut the sheathing and make issues later.