Tachometer issues

[lords88]

I just bought a sled and it has two tachometers on it and they both read different RPM's. One is digital and one is mechanical the digital one reads 1,000 rpm higher at idle. My engine is a triple, could one of the gauges be for a twin? Would that make a difference, and how do I figure out which one is right? I don't want to over rev this engine. Thanks in advance.

 

[motorman]

you need a 3rd tach,i would use my hand held to compare at different rpms.
good luck D

 

[Ex-Member]

Sounds like there's something mechanically wrong with the analog one.

Digital one probably uses a hall-effect sensor (solid-state). Those have incredibly high MTBF's and are rather accurate. From there, it depends on the A/D and clock in the circuit that reads that sensor. Again, solid-state devices with high reliability. That stuff either works or it doesn't, the error is going to be negligible.

I'd rip the analog one out and throw a temp sesnor or two in its place.