Calibrating a Tach

The Koso TnT tach I installed is a bit spastic when reading the RPM's. From what I read on other sites some people connected it to the one of the wires coming off the stator. Before I go and try that, i wanted to see if that made sense to any of you.

I currently have it connected the same way the stock 82 xj650 maxim has it, coming off the coils. Its currently slow to read and doesn't like to go past 5k. My other theory is maybe the preset RPM settings are wrong and for a 4-cycle - 4 piston bike it had the RPM signal set as 1 RPM per 2 ignition. Is that right?

Thanks for the help

 

which model do you have?

TNT-01 hook ups


different ways to hook it up

 

there is also t functions that need to be set

RPM pulse HI or LO
RPM input signal number setting
tnt -01 instructions
http://kosonorthamerica.com/instructions/BA035W00.pdf

 

All that was done and its not registering as accurately as it should. Thought maybe by changing the hookup to the stator (read how someone did it on another site) it might work better. Just don't know if it makes sense for our bikes. I don't see how connecting it to the alternator/stator would work, shouldn't it connect to the pickup instead?. I also thought maybe their internal setting in regards to rpms to ignition count might be wrong . For a 4-cycle 4-piston they have it set as 1 RPM per 2 ignition.

I have it connected to the coil with the orange wire like my stock tach was connected. So it should work fine.

I have the tnt multi.

 

our bikes have what is called wasted spark ignition. the plug fires every stroke

this is your setting
For a 4-cycle 4-piston they have it set as 1 RPM per 2 ignition.
there is also another setting for hi-lo depending on where you hook wire dark brown


do not connect to alternator.

the link above is the directions for your meter.

where did you hook the 1 hots to.
instructions show red constant power at battery or red on ignition switch.
the other wire is to brown wire to fuse block remaining fuses
black wire to ground if long enough connect to battery ground terminal.


DARK BROWN to rpm pick up source
connect to coil wire gray or orange which ever coil you use that should be the negitive side of coil
or wrap it at least 5 times around spark plug wire
other methods too , side of coil inside of cap with proper connector....

 

I guess I'll mess with it some more. The way i have it follows the instructions by connecting it to the coil. It shows an rpm reading. Just not steady.

Power and ground are connected directly to the battery.
Tried wrapping the spark plug wires and its all the same result. Guess I'll try wiring it to the pickups.

Is there a way to test and confirm if 1 rpm per 2 ignitions is an accurate read for our bikes. I would think it should be higher. 1 rpm to 4 ignitions to complete a cycle.

 

yamaha 1 coil at 2 sparks per rpm
your tach should be set to measuring 1 rpm per 2 ignitions 4 cylinder.

 

1 RPM per two ignitions is correct. The tach only gets/needs signal from one coil, not both.

 

I put a TrailTech on a long time ago and even though 1 per 2 seems right, I think it worked at 1/1.

 

I'll try that, i didnt think about going down in numbers. Thanks

 

You might also need a resistor in series with that wire. I used 1.5 meg ohm because that's what I found, they recommend 1 meg ohm.

 

Brown
Black Or green
Green
Silver