WHAT DOES THE TACHO RUN OFF??

[cally]

Hi Guys,
A question...
What does the Tacho run off on a ZXR750J2??
Trying to problem solve...
Was on the M4....doing 100klms, then scooter spluttered and engine died, then came back on, died again, then back on...
Then kept going...didn't miss a beat after that....Has happened once or twice again since...
When this happened.....I noticed that the tacho went straight to Zero then back to 4K
Each time it died, the needle went to zero and then back to 4K...so, dirty fuel ETC is out!!!
Any ideas ppl??
Cheers!

[tim]

Losing electrical power?

[ducati_paul]

Each time it died, the needle went to zero and then back to 4K...so, dirty fuel ETC is out!!!

Why? Dirty fuel means the bike wouldn't run, if the bike doesn't run the RPM is zero!?

[Glen]

Did someone say Taco. Mmmmmmmmmmm Taco.............

[BrettZZR]

I think he meant the bike stopped pulling (engine still turning with the back wheel) and the rev counter flicked to zero, and then flicked back up to the actual RPM the instant it started pulling again...

This is typical of electric rev counters. They 'count' pulses from the ignitor to give a reading.

So either:
the ignitor has a bad connection / intermittent problem, and for that time stops sending pulses
or:
there is an electrical problem that interrupts the supply to the ignitor to make the pulses
or:
there is an intermittent problem with the crank sensor (in the older bikes days they were always on the one end of the crank?) so stops sending the trigger to the ignitor...

(-8

[Gosling1]

check your battery leads at the battery terminals, and also the main earth lead on the motor. Sounds like they could be either loose or have some corrosion. If you undo the earth lead that is bolted into the motor, give it a really good clean and re-install. This one is almost always overlooked when checking out electrical issues.