Help me fix my tach!

[corksil]

Hey guys, new bike and the first order of business is fixing the tachometer.

It says the bike is idling at 3krpm, which isn't correct.

As the bike revs up, the tach barely moves and never goes over 5k. Sometimes under hard acceleration it just shuts off instantly and snaps down to zero.

I'm a mechanic, so I'm used to diagnosing and troubleshooting cars but someone give me a place to start..

I think the first order of business is pulling off all the fairings and looking for loose wires, stretched hoses, and any fluid leaks that need to be fixed.

Where do I start? And am I correct to assume that the battery is under the seat?

Thanks!

[nightrider]

Originally Posted by corksil

Where do I start? And am I correct to assume that the battery is under the seat?

Thanks!

yes, it should take about a minute to take off. Remove the side panels and then the two allen bolts holding the seat. Make sure the battery connections are tight. My tach did funny things too when they got a little loose.

[corksil]

Originally Posted by nightrider

yes, it should take about a minute to take off. Remove the side panels and then the two allen bolts holding the seat. Make sure the battery connections are tight. My tach did funny things too when they got a little loose.

Thanks! I've done a little reading since I made this thread, and it seems like battery/charging connections are the number one cause of gauge problems.

I will get into this today, or as soon as my part-order arrives and I do all kinds of maintenance at once. I kinda don't want to take the bike apart... because then I can't ride it until my parts arrive >.<

Anyone else have suggestions? If my battery connections are tight and clean and the battery tests correctly for voltage/charging/starting, where's the next place to look?

Thanks!

[corksil]

Where else should I look for a problem?

The tachometer reads ~3k at idle (bike is definitely not idling that high)

Revving it causes the tach to climb, very lazily and never higher than 7k.

[What sounds to me like] 10k+ ACTUAL rpm causes the tach to shut off abruptly and the needle falls to zero.

I did the 'tach test' -- when you remove the wires from the back and see if the needle jumps/moves and everything seemed to test fine. Removing either of the signal wires made the needle drop to zero.

I polished the battery terminals, changed the spark plugs, polished the electrical connectors on the igniter coils.. I have checked every single plug for corrosion and found none.. I have removed the engine ground and polished it...

I've done everything I can at this point -- I need information. How does this system work? How can I check the tach signal wire for adequate range/reading?

Anyone?

[Motofool]

Originally Posted by corksil

............Anyone?

A tachometer in good condition just counts the number of sparks that the CDI commands.

Many new-gens have had problems with that, being the CDI the culprit.

Please read this:
http://www.ninjette.org/wiki/Ignitor_problem

[corksil]

Yes I have been all through most of the links that are related to this issue. I'm well aware that there have been massively documented issues with the CDI and tach on these 250r's.

As stated in that link -- seems like the common solution is to replace either the tachometer or CDI and hope for the best.

I completely tore down the bike when I did maintenance and didn't find evidence of anything else that could be contributing to the problem.

Please help me fix this. So if I'm looking at a new CDI, this would work for me?

And as for replacing the tach -- I'd have to replace the entire cluster? I didn't see any way to pull just the tach itself out of the cluster.

Feels like I'm shooting in the dark. Who's to say that replacement used ebay parts aren't just being sold off to people like me for the exact same reason that I'm looking for replacements..

[corksil]

And is there any way to test the signal that's going to the tach? I have clear access to the wires...

Can't I just put a multimeter on there and test it somehow?

[Motofool]

Originally Posted by corksil

And is there any way to test the signal that's going to the tach? I have clear access to the wires...

Can't I just put a multimeter on there and test it somehow?

As far as I know, these tachometers have a micro-controller that collects information by counting the input pulses to calculate the rpm.
They work based on frequency; therefore, a multimeter will not be useful to you.

As for replacing the tach; I am not familiar with the new-gen bikes.