Got my new instrument cluster in today, it's a chinky knock off but it was cheap, and the tach doesn't want to work properly.

I thought I had read somewhere or been told by someone that with an aftermarket tach you have to use a resistor or something along that line inline to help steady the electrical current and get an accurate reading.

I could be wrong but if I happen to correct what is it exactly I need to use and what size?

I've tried using the original wire that went to the stock tach, wiring it to the first coil, and even wrapping it around the plug wire for the first cylinder but I can tell that the readings are off and the needle will just drop after 7k.

I'm fairly certain it's not any of the settings in with the tach itself as I went thru and adjusted every setting while it was running to see if there was any change but the closest I got was switching it from 4 cylinders to 2 which just caused it to read way too high.

It could possibly just be the gauge itself since it is a cheap piece of equipment directly from china but I figured I'd ask before sending the shipper a not so nice message haha.

Thanks guys in advance

 

Just read on some car forum that it's best to use a 470 ohm or 10k resistor to stabilize the signal, they're talking about cars but I'm not sure if this will do the trick on a motorcycle.

I can pick up a 5 pack cheap at orielly's so I'll try that and see what the end result is

 

So....I'm guessing its reading twice what it should, on 4-cylinder mode, because it uses the wasted spark method where it sparks twice as much as a normal system? Is there an 8 cylinder setting?

 

There's only a 4 and 2 cylinder mode, the 470 ohm resistor did the trick but the original wire for the tach still didn't want to work properly.

Wired it directly to the first coil, wired the resistor into it, and set it to 2 cylinder mode and she's reading dead on.

 

That'd do it. ! - smart thinking