Tachometer starting to show its age?

[Capn Ron]

Hi all,

I was just getting my '92 FJ ready for the ride to the Reno Air Races this Friday...changed the oil, lubed and adjusted the chain and a little wipe-down.  Nothing dramatic for sure...and nothing that I can figure would cause an odd tachometer behavior.

Bike starts and runs like a top.  It idles great and sounds to be at the RPM I'm used to (right around 1,100 RPM), but the tachometer indicates ZERO.  The needle just sits on the pin.  If I rev the bike up to what I'm imagining to be 3-4,000 RPM, the tachometer needle will rise, but maxes out at an indicated 1,000 RPM.

I rode the bike two weeks ago with no tachometer trouble...the bike has never had gauge issues.  It's just sat in the garage until today and now this.  Any thoughts on the cause?

[Country Joe]

Hi all,

I was just getting my '92 FJ ready for the ride to the Reno Air Races this Friday...changed the oil, lubed and adjusted the chain and a little wipe-down.  Nothing dramatic for sure...and nothing that I can figure would cause an odd tachometer behavior.

Bike starts and runs like a top.  It idles great and sounds to be at the RPM I'm used to (right around 1,100 RPM), but the tachometer indicates ZERO.  The needle just sits on the pin.  If I rev the bike up to what I'm imagining to be 3-4,000 RPM, the tachometer needle will rise, but maxes out at an indicated 1,000 RPM.

I rode the bike two weeks ago with no tachometer trouble...the bike has never had gauge issues.  It's just sat in the garage until today and now this.  Any thoughts on the cause?

Ron,
I have to give my tachometer a rap with a knuckle when I first start the bike up. It's been that way for about 3 years. Once it is moving, it works fine the rest of the day.
Joe

[Firehawk068]

Lack of morning coffee...........................

[FJmonkey]

Ron, I think your tach sleeps in much later than you... 

[Capn Ron]

Ron, I think your tach sleeps in much later than you... 

That's not possible!   

[red]

Capn Ron,

I'd bet money on corroded ground wiring.  Clean the connectors, first thing.  If that does not fix the tach, rig in a temporary ground wire to be sure.  If that fixes the tach, track down the faulty connection.  After that, things can get more complicated, but start after the simple stuff first.

Cheers,
Red

[Capn Ron]

Hey Red!

My money's on a grounding issue as well...but since I'm heading out for a trip day after tomorrow, I thought I'd run it by the collective here before I started tearing into my ride!  Chasing down a grounding issue somewhere would likely involve pulling the crispy plastics?   

[Capn Ron]

Ron,
I have to give my tachometer a rap with a knuckle when I first start the bike up. It's been that way for about 3 years. Once it is moving, it works fine the rest of the day.
Joe

Hey Joe,

Thanks for the input.  In your case, did it seem as if the tach was mechanically sticking and a rap with your knuckle would unstick the needle?  Mine appears to act like more of an electrical issue...it does move, but only after revving the engine and even then, it tops out at 1,000 RPM indicated.  This is repeatable with every twist of the throttle.

[Country Joe]

Ron,
I would say my issue is mechanical. Since  I have the fairing off right now, it is probably a good idea to see if a little lube and maintenance won't fix the problem. Yours definitely sounds like an electrical problem.
Joe

[Firehawk068]

Mine used to stick when it was cold...............When I would first start it in the morning.........................
But when I say it would stick..................I mean, the needle would physically stick to the zero-pin!
I ended up taking the cluster apart, and cleaning the pin with some alcohol (it somehow over the years, became sticky)
My guess would be vapor, mixed with particles from various lubricants from the speedometer and/or cable that made a sticky film of some sort.

Anyway, I don't think your issue is the same as that................Your issue does sound like a wiring or ground issue..................You stated that you DO get a reading when you rev her up.............Just not the intended reading for the rpm that you seemingly rev it to...................

[Capn Ron]

Mine used to stick when it was cold...............When I would first start it in the morning.........................
But when I say it would stick..................I mean, the needle would physically stick to the zero-pin!
I ended up taking the cluster apart, and cleaning the pin with some alcohol (it somehow over the years, became sticky)
My guess would be vapor, mixed with particles from various lubricants from the speedometer and/or cable that made a sticky film of some sort.

Anyway, I don't think your issue is the same as that................Your issue does sound like a wiring or ground issue..................You stated that you DO get a reading when you rev her up.............Just not the intended reading for the rpm that you seemingly rev it to...................

I had to laugh Alan...I read the description of your problem and pictured that needle being stuck to the pin on a cold morning like a tongue stuck to a flagpole!   

This definitely isn't something I have to fix before the trip...Maybe when I get back, I'll pull the fairing and run contact cleaner through every connection...and check all my grounds.  The bike's seen 30,000 miles and a lot of wet weather since the rebuild!

[Pat Conlon]

Ron, pull the tank, down at the coils, emery cloth clean those connectors...I forget which color wire, but one of them feeds the signal to the tach.

Do we have a head count?

[Capn Ron]

Ron, pull the tank, down at the coils, emery cloth clean those connectors...I forget which color wire, but one of them feeds the signal to the tach.

Do we have a head count?

Hey Pat!

Thanks for pointing me at something specific.  I'm heading out to the garage to check out that coil pickup!

Headcount looks like four:  You, Paul, Mike (although I haven't heard from him in two days) and me.  I heard that any more than three FJ's is a rally...so I'm still callin' it the RR 2014!

[Capn Ron]

Hey Pat!

Just got off the phone with Mike and he can't get the time off.  Looks like it's just me and you two.  I'm heading into the garage to check on the tach wiring connectors.

[FJ_Hooligan]

Ron, pull the tank, down at the coils, emery cloth clean those connectors...I forget which color wire, but one of them feeds the signal to the tach.

I think the Grey wire feeds the tach.  Not sure which coil it is.  Do make sure the coil to frame ground wire is, uh, grounding!