Gauges Repair

[haybaler]

Isn't there a local outfit that takes gauges apart, cleans, lubes, calibrates?(tach/speedo, 1985 Cb650 Nighthawk)

 

[auntiebling]

palo alto speedometer. they might decline your gages, if they take the work it'll be spendy.

i don't know that anyone calibrates them per se, since there isn't really much to adjust inside one, it works or it doesn't. i suppose the tension on the needle spring could be fiddled with.

there is another outfit in the LA area, hollywood speedometer or something like that.

what's wrong with them? an 85 nighthawk isn't all that collectible is it? there writeups out on the internet to DIY honda motorcycle gage rehab. getting the crimped on band apart is the trickiest part especially if you're worried about aesthetics. I wasn't on some old goldwing gages and cut the band, reassembled with some RTV to hold the band in place and the rest was delicate but straight forward.

 

[haybaler]

"what's wrong with them?"

Unusual symptoms:
Bike starts and revs up on choke, no movement in tachometer.
Warm up for 5 minutes, reduce choke, no movement in tachometer.
Pull in clutch, throw it in first, no movement in tachometer.

Let out clutch, increase throttle, roll about 10 feet,
...tachometer jumps to life!

So, I need less of a calibration, and more of a diagnosis, or at least a way to troubleshoot the problem. Bike sat for many years, only 16,500 original miles, runs strong. Not collectible, true, so not worth huge $$ investment. Just curious what would cause these symptoms?

 

[seadog]

Isn't there a local outfit that takes gauges apart, cleans, lubes, calibrates?(tach/speedo, 1985 Cb650 Nighthawk)

Speed O Tach in Concord.

 

[haybaler]

Speed O Tach in Concord.

Yep, I think that's the one I remember seeing awhile ago, thanks!

 

[auntiebling]

"what's wrong with them?"

Unusual symptoms:
Bike starts and revs up on choke, no movement in tachometer.
Warm up for 5 minutes, reduce choke, no movement in tachometer.
Pull in clutch, throw it in first, no movement in tachometer.

Let out clutch, increase throttle, roll about 10 feet,
...tachometer jumps to life!

So, I need less of a calibration, and more of a diagnosis, or at least a way to troubleshoot the problem. Bike sat for many years, only 16,500 original miles, runs strong. Not collectible, true, so not worth huge $$ investment. Just curious what would cause these symptoms?

Sounds like dried up gooey grease to me.

 

[CDONA]

Cable driven or electronic?

My Triumphs cable driven speedo is temperature sensitive.
If it gets hot around 100*, internal grease will melt and the needle won't move.
Until I get rolling above 20, so I can pound the speedo and shock it back to operation.
The bike cover I use contributes to this issue, for it magnifies trapped heat.
Life in Az,

 

[bobl]

A quick look at Ebay shows at least half of a dozen tach/speedo combos. It would probably be cheaper to replace than to pay someone to repair.

 

[haybaler]

just replace entire unit

A quick look at Ebay shows at least half of a dozen tach/speedo combos. It would probably be cheaper to replace than to pay someone to repair.

Yes, my thinking exactly!

It's just that damned curiosity about the symptoms;
I've seen some strange stuff on motorcycles, but
this one is really mysterious;

I would like to know the cause.

 

[GPzPop]

Yes, my thinking exactly!

It's just that damned curiosity about the symptoms;
I've seen some strange stuff on motorcycles, but
this one is really mysterious;

I would like to know the cause.

how is the cable looking? is it (the center spinney part) in one piece from motor to tach?

 

[haybaler]

No cable. It's a 1985 with the then newfangled electronic tach, 3 wires attach to the back of the tach unit. A friend on the Nighthawk Forum suggested a broken internal solder connection, so either I'll take it all apart and look, or ask the folks at Speed o Tach in Concord.

I just can't get over the consistent behavior after rolling 10-15 feet, even does it if I use the centerstand, put it in 1st and spin the back wheel. But I know back wheel movement has no possible connection to the tach, right?

 

[bobl]

Maybe you could hook a volt meter to the leads, and spin it, if it will do it on the centerstand, and see if it's is the signal, or the tach itself.

 

[auntiebling]

Electronic!? Nevermind anything I said. That shit is voodoo

 

[haybaler]

Not Voodoo, but similar

So today, I started engine, ran for a few minutes, then smacked the tach a few times, and Voila, tach works! So if I ever sell the bike I can just tell new owner to Smack the Tach!! and everything will be okay.

"A friend on the Nighthawk Forum suggested
a broken internal solder connection"
Sounds like a good lead; please stand back in the safety area, and I will attempt a complete disassemble of the tach speedo assembly, find the problem.

Cheers!

 

[RVFRick]

From the symptoms my guess is it's aged lubricant, contamination or wear to the needle's pivot that is causing binding of the delicate needle. A shock or jarring vibration helps break the initial friction and frees it from the sticky resting position. Just give it a smack after start up. Harkens back to the abuse inflicted on our tube based Philco TV we beat on until we got decent reception :laughing

 

[seadog]

So today, I started engine, ran for a few minutes, then smacked the tach a few times, and Voila, tach works! So if I ever sell the bike I can just tell new owner to Smack the Tach!! and everything will be okay.

Percussive engineering at its finest.:thumbup

 

[haybaler]

And I sold the bike to a musician, so I think the percussive part is quite appropriate. As I told him, I suppose it's all fixable, but it's a 36 year old motorcycle, everything ain't gonna work perfect, right?