Curvy tacho faulty. - SV650.org

09-09-14, 06:28 PM

I've got a 99 curvy, I went to it this morning turned on the ignition and the tacho needle shot round to the stop and stayed there, this is before I started the engine. With ignition turned off the needle stays round at the 4o'clock position. The engine runs fine, what's going on?
Mark P.

DarrenSV650S · 09-09-14, 06:34 PM

09-09-14, 06:37 PM

No thats a pervy tacho!

10-09-14, 06:40 PM

Had another look at the bike tonight, I disconnected the battery and left it off for bit reconnected it again but still have the same fault ie needle goes round to the stop with ignition turned on but engine unstarted,still stays in the 4o'clock position with ignition off. Any ideas what could be the matter and will I kill the ignitor box if I use it? It runs fine with no misfires or the like. What's it all about?

11-09-14, 07:21 AM

Check the connectors on the front coil pack (feeds the tacho) its located to the left of the airbox under the tank (if you are sat on the bike)

Just try disconnecting, clean the contacts and make sure there are no breaks in any of the wires. It may be something more but this is where I would start

andrewsmith · 11-09-14, 02:20 PM

If the connector is fine, you'll need to test the speedo. Its about a £2.50 job

It does sound like your speedo sender (the out part) has bit the dust

11-09-14, 06:31 PM

You reckon that the speedo sender is at fault, didn't realize it would be linked to the tacho but come to think of it the speedo had a bit of a brainstorm ( it went dead momentarily) the same time the tacho went fut! the speedo seems ok.

Sid Squid · 12-09-14, 06:34 PM

Tachometer and speedo pickups are not connected or reliant on each other.
OP: I suspect the tacho is knackered, if it doesn't go back to zero when the battery is disconnected then the wiring isn't relevant and the instrument itself isn't working right.
There is no 'coil pack' there are two coils, the tacho has a single connection to the front coil LT- and simply counts the pulses from the ignition unit to deduce engine speed.
Seeing as the engine runs OK then the coil connections are proven good, clearly the connection from the coil to the instruments inside the loom could be broken, but if it were then the tacho would simply not work.

12-09-14, 07:04 PM

Thanks Sid, had a look at the wiring can't find any faults with it. I didn't think speedo and tacho were linked. Turned again today still hits the stop! Do you think I will hurt the ignitor box if I keep riding it?

13-09-14, 11:58 AM

What is the best way to disable the tacho without cutting too many wires?

09-09-14, 06:28 PM	#1
Mark P Guest Posts: n/a	Curvy tacho faulty. I've got a 99 curvy, I went to it this morning turned on the ignition and the tacho needle shot round to the stop and stayed there, this is before I started the engine. With ignition turned off the needle stays round at the 4o'clock position. The engine runs fine, what's going on? Mark P.

09-09-14, 06:34 PM	#2
DarrenSV650S Member Mega Poster Join Date: Jul 2006 Location: Dundee Posts: 4,404	Re: Curvy tacho gone wild.

09-09-14, 06:37 PM	#3
Mark P Guest Posts: n/a	Re: Curvy tacho gone wild. No thats a pervy tacho!

10-09-14, 06:40 PM	#4
Mark P Guest Posts: n/a	Re: Curvy tacho faulty. Had another look at the bike tonight, I disconnected the battery and left it off for bit reconnected it again but still have the same fault ie needle goes round to the stop with ignition turned on but engine unstarted,still stays in the 4o'clock position with ignition off. Any ideas what could be the matter and will I kill the ignitor box if I use it? It runs fine with no misfires or the like. What's it all about?

11-09-14, 07:21 AM	#5
Corny Gizmo Guest Posts: n/a	Re: Curvy tacho faulty. Check the connectors on the front coil pack (feeds the tacho) its located to the left of the airbox under the tank (if you are sat on the bike) Just try disconnecting, clean the contacts and make sure there are no breaks in any of the wires. It may be something more but this is where I would start

11-09-14, 02:20 PM	#6
andrewsmith Member Mega Poster Join Date: Apr 2010 Location: Newcastle upon Tyne, Just south of salad dodging country Posts: 7,750	Re: Curvy tacho faulty. If the connector is fine, you'll need to test the speedo. Its about a £2.50 job It does sound like your speedo sender (the out part) has bit the dust __________________ RIP Reeder 20/07/1988 - 21/03/2012. Always missed squire!!! Every year we meet old friends, gain some new ones, lose old ones and you always remember them all. “Live as if you were to die tomorrow. Learn as if you were to live forever.” Mahatma Gandhi

11-09-14, 06:31 PM	#7
Mark P Guest Posts: n/a	Re: Curvy tacho faulty. You reckon that the speedo sender is at fault, didn't realize it would be linked to the tacho but come to think of it the speedo had a bit of a brainstorm ( it went dead momentarily) the same time the tacho went fut! the speedo seems ok.

12-09-14, 06:34 PM	#8
Sid Squid No, I don't lend tools. Mega Poster Join Date: Jul 2003 Location: Skunk Works, Nth London Posts: 8,680	Curvy tacho faulty. Tachometer and speedo pickups are not connected or reliant on each other. OP: I suspect the tacho is knackered, if it doesn't go back to zero when the battery is disconnected then the wiring isn't relevant and the instrument itself isn't working right. There is no 'coil pack' there are two coils, the tacho has a single connection to the front coil LT- and simply counts the pulses from the ignition unit to deduce engine speed. Seeing as the engine runs OK then the coil connections are proven good, clearly the connection from the coil to the instruments inside the loom could be broken, but if it were then the tacho would simply not work. __________________ If an SV650 has a flat tyre in the forest and no-one is there to blow it up, how long will it be 'til someone posts that the reg/rec is duff and the world will end unless a CBR unit is fitted? A little bit of knowledge = a dangerous thing. "a deathless anthem of nuclear-strength romantic angst" Last edited by Sid Squid; 12-09-14 at 06:42 PM.

12-09-14, 07:04 PM	#9
Mark P Guest Posts: n/a	Re: Curvy tacho faulty. Thanks Sid, had a look at the wiring can't find any faults with it. I didn't think speedo and tacho were linked. Turned again today still hits the stop! Do you think I will hurt the ignitor box if I keep riding it?

13-09-14, 11:58 AM	#10
Mark P Guest Posts: n/a	Re: Curvy tacho faulty. What is the best way to disable the tacho without cutting too many wires?

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