Tach reading lower rpms than bike is running.

[06bigdogk9]

Hi, I have an 06 K9 carburated, has the new EHC, recently started reading about half the rpms it's actually running, lights flash at idle because of it. I thought it was a coil issue, so I replaced that with no luck. Any ideas? Maybe a crank sensor? Thanks in advance

 

[mleach72]

Hi, I have an 06 K9 carburated, has the new EHC, recently started reading about half the rpms it's actually running, lights flash at idle because of it. I thought it was a coil issue, so I replaced that with no luck. Any ideas? Maybe a crank sensor? Thanks in advance

Was the ignition changed recently?

 

[06bigdogk9]

I upgraded the ehc last year, I believe it came with a new ignition then. Other than that, no

 

[mleach72]

I upgraded the ehc last year, I believe it came with a new ignition then. Other than that, no

Did this problem start after the change? This sometimes happens when installing the thunderheart programmable ignition. It will cause the tach to read half or twice. Maybe changing the ehc can have the same effect. Anyways, you need to hook up a computer to change the tach calibration. You need a special cord and the thunderheart software.

 

[06bigdogk9]

Changed that about 4k miles ago, been fine ever since until the last couple hundred miles. Sucks, the nearest custom bike shop is over an hour away.

 

[mleach72]

Changed that about 4k miles ago, been fine ever since until the last couple hundred miles. Sucks, the nearest custom bike shop is over an hour away.

Hmm, I don't know why it would do that all of a sudden then. I can send you the cord and software to try it, so you don't have to spend money on something that may not work. Where are you located?

 

[Rottweiler]

What EHC did you use?

 

[Jwooky]

The EHC does not control the tach. The tach reads the pulses directly and had its own chip on it.

 

[Mickmorris]

Welcome from Florida! Check your tach ring. Could be the issue. Any loose connections there will make it do crazy shit.