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Discussion Starter #1 (Edited)
So, after several weeks of maintenance on the old curvy, I finally got her road-worthy, inspected and ready for summer. Suddenly, while riding yesterday, my speedo started dancing a bit, then stopped working completely.


The Symptoms

While accelerating/on throttle, speedo and odo worked, but the needle did dance a bit.

Coasting/off throttle, needle dropped to 0 and no changes on odo. Within an hour (I was a good ways from home), the needle slowly stopped responding altogether, until now it's just dead, and odo is not counting miles.


Analysis

I. Checked all connections to ensure there was nothing loose, no obvious corrosion or broken wires, and checked battery terminals.

II. Removed front wheel and inspected speed sensor, which appears to be in perfect working order without any teeth damaged or broken on the spindle.

III. With front wheel off the ground, power ON, but engine OFF, I was able to get the gauge to register speed while manually spinning the wheel as fast as I could. Weird.

IV. Went through TeeRiver's speed sensor multimeter tests per his YouTube video and this thread. Here's my results:

  1. Voltage - Speed Sensor Supply (from gauge): 12.1v (normal spec)
  2. Current - Speed Sensor Supply (from gauge): 108.9 - 109mA (higher than spec?)
  3. Current - Speedo Sensor current draw test: 4.4mA (also higher than spec?)
  4. Current - Speedo Sensor signal output test: 0v to ~4.8v as wheel turns (normal spec)
I'm not sure if #2 and #3 above are actually showing me a possible issue, or if they're in spec. The sensor supply has a 100mA resistor inline, so it's supposed to keep current to 100mA (as I understand it).

At this point I could try replacing the entire sensor unit (~$150), but I question if that will solve it, based on the health of my current sensor.... or, I may have to replace the speedo gauge itself.

Another thought is the R/R, but these symptoms don't typically point to that...? So here's what did for that:


Battery - R/R Test

Additional Info: I upgraded my R/R several years ago with the recommended MOSFET unit off a Honda CBR after the OEM unit failed. I've just checked voltage at the battery terminals and got the following readings (based on PriestTheRunner's test):

  1. Battery Only (fully charged): 14.1v
  2. Lights Only - 30 seconds: 13.07v
  3. Lights Only - 3min: 12.97v
  4. Bike Running - Low Beams at idle: 13.42v
  5. Bike Running - High Beams at idle: 13.42v
  6. Bike Running - High Beams at 5k: 13.42v
So my voltage at the battery while running is a hair lower than spec, but still consistent throughout the rev range, and accessory scenario. Could this be a potential sign?

I have spent all day searching and reading the many threads on this subject, but can't come to an educated conclusion at this point.

Any suggestions, help or insights would be greatly appreciated! :worship:
 

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Check the charging voltage across the battery.I recently had some Speedo/Rev counter bouncing.Turned out to be the Regulator part of the R/R failing causing battery over-charging.

As the R/R was around 20 years old I didn't mind fitting a new one but decided it was a good time to upgrade to a MOSFET one.

I looked around at some of the links but many photo links were broken so decided to chronicle the job and make some Webpages.

This may not be the cause but hope it will be helpful just in case.I'm still putting finishing touches to it as I may fit a small cooling fan to it this week,

http://puttingoutfires.x10host.com/MosfetFH020AA/MosfetUniRR.html

HTH :)
 

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Excellent and thorough job tracing the problem so far, Kaliozone.

The sensor voltage and current tests you have made (as described in the video) indicate the sensor is fine. So long as the values are close, it is okay. Basically you are looking for short, open, or no voltage condition, anything close to "normal" is good.

By far, the most common SV650 speedo problem is a broken rotor magnet at the sensor. The rotor is brittle and will break easily if not properly lined up when installing the front wheel.

The second most likely problem, as Strat mentioned, is too low, too high, or flaky battery voltage. Too low voltage from a low battery, too high voltage from a failed R/R, or flaky voltage from loose or corroded battery terminals, any of those will cause a problem.

So far, it looks like you have eliminated the rotor and voltage as potential problems.

At this point, it looks very much like the gauge itself has failed. Did you happen to notice if the odo and speedo ever failed independently? That is, did the odo ever work when the speedo did not, or vice-versa? If so, then for sure the gauge is bad since odo and speedo share the same signal. If the signal were bad they would fail in unison.

Are you the original owner? Is the R/R stock? A failed R/R is very common on the gen1 SV. If the R/R fails in high voltage mode (>15v) it can fry the gauge electronics (the spark ignitor too). The failure does not have to be immediate, it is possible to have a "walking-wounded" gauge that once stressed may crap out at some random time in the future.

If your multimeter happens to have a Hz (frequency) setting, you can clip it to the speed sensor signal directly at the gauge connector, go for a ride, see if you get a Hz reading. This will give you a "live" reading and is a conclusive test. If a frequency signal is present but still no speedo or odo reading, then for sure the gauge is bad.

Failing that, you can open the gauge and do a visual inspection. Look closely for any sign of heat damage.
Also, look for broken solder joint(s). But be aware, a cracked joint may be obvious but often can not be seen with the naked eye, or even with magnification. A brute force option is to reflow all solder joints, see if that fixes the problem.
Good luck.
 

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Discussion Starter #5
Tee - thanks so much for taking the time to reply... I really appreciate your expertise! A few additional data points, per your questions:

  • Original owner (I bought the bike brand new in 2000 :naughty:)
  • OEM R/R failed about 8 years ago. Replaced with the forum's recommended MOSFET R/R off a Honda.
  • That failure event fried my tach, which was replaced when doing the R/R replacement. Speedo never had an issue.
  • The speedo failure happened within a few miles of riding, so I wasn't able to really assess if the odo worked while the speedo didn't.
  • The odo is definitely NOT working as well, but it does display static mileage and trip... just not adding miles.
One thing that was strange was that I was able to get the speedo to register some speed when I had the front of the bike jacked up, and I spun the front wheel as best I could (power on, engine off).

I'll confirm this by going for a ride and cutting the engine... If that's the case, perhaps I am somehow getting a slight power surge at the cluster from the charging system?

I'll do this tomorrow, along with trying the Hz function on my meter (if mine has it). From there, I'll pull apart the cluster and see if there's anything obvious.

Thanks!!
 

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Wow, original 2000 owner! :worship:

I am sorry to say (and you likely know) Naked SV gen1 gauges are hard to find. Hopefully the problem is not the gauge. I wish manufactures would post tech specs (like schematics and parts) when their products approach obsolescence.

Here is a thread from last year about a fried gauge resistor inside a gen1 gauge. Unfortunately no success, more than just the resistor must have fried.

... One thing that was strange was that I was able to get the speedo to register some speed when I had the front of the bike jacked up, and I spun the front wheel as best I could (power on, engine off).

I'll confirm this by going for a ride and cutting the engine... If that's the case, perhaps I am somehow getting a slight power surge at the cluster from the charging system?
Not a power surge, more likely something is damaged, the electronics are working at the "hairy edge" and lower voltage (engine not running) is enough to get it to work. It will be interesting if you can replicate this.
 

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I suspect my Rev counter is not long for this world after over-voltage charging.As Teeriver says the 1st gen clusters aren't common.

I may go for a cheapie replacement.

https://www.ebay.co.uk/itm/15000rpm-Motorcycle-Universal-LCD-Digital-Speedometer-Tachometer-Odometer-UK/192547377897?hash=item2cd4b7d2e9:g:O9EAAOSwOwZZhFBQ

as the the circuit board that the Rev counter is attached too doesn't seen available separately in my case so you have to buy the whole unit at 261 euros over here.

I've sent for a cheap inductive rev counter for now as the jumping/intermittent needle on mine has become annoying.

https://www.ebay.co.uk/itm/Digital-Engine-Tach-Tachometer-Hour-Meter-Inductive-for-Motorcycle-Motor-WE/192546216736?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

I'm most likely going to disconnect the Rev counter on mine for now and stick this on the glass for now.

Although I'm qualified in Electronic servicing I don't have the test tools or ability to reconstruct the Circuit board but fortunately I have a pal in Finland who is an Electronic Guru.He can reverse engineer nearly anything and can usually make something newer and better.

After the season is over over here I'll take the board off and hopefully send it to him :)

Back to the OP.A cheap new Cluster might be the way to go.For what they cost it's worth an educated punt IMHO.

]
 

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Discussion Starter #8
Bringing this thread back on topic (Speedometer and Odometer):

Any additional thoughts from the forum on this? I've put another 150 miles on the bike, and the speedo/odo are still DOA. Every 20 minutes or so, I'll see the speedo react (needle jumps up from zero), but otherwise stays at zero.

Before diving into a complete sensor and/or gauge replacement, I may just replace the R/R again, since it's about 8 years since the first replacement...

Thoughts?
 

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If you get to the point of trying a new sensor, hit me up. I have a sensor and rotor from an '01 I can send for the cost of shipping.

Sent from my XT1575 using Tapatalk
 

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...Every 20 minutes or so, I'll see the speedo react (needle jumps up from zero), but otherwise stays at zero.

Before diving into a complete sensor and/or gauge replacement, I may just replace the R/R again, since it's about 8 years since the first replacement...

Thoughts?
This is not an R/R problem (though a failed R/R could have damaged the speedo in the first place).

The stock SV R/R is a ticking time bomb and should be replaced no matter what but if you have a good MOSFET replacement R/R in the bike already, you should never have to replace it, they do not wear out.

Did your multimeter have a frequency setting. That would tell you for sure without having to replace the sensor.

If you are into doing a science experiment, and who isn't :naughty:, you could hook up an LED to a 200 ohm resistor, place that between the speedo signal and ground, that would flash each time the speed sensor triggered and let you know if the signal were active or not.

But looks like you already have a new sensor coming, that will narrow down the problem.

Please keep us updated on what you find.
 

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Discussion Starter #13
Tee - thanks for the reply/confidence in it not being the R/R. That was a task (and expense) I was hoping to avoid doing a second time.

As noted, Superdog - being super - is sending a replacement speedo sensor... an inexpensive and easy test.

My multimeter did not have the Hz setting (it's a pretty basic one), so I could try the LED trick. I had tested the signal output per your Youtube vid and was getting in-spec readings when spinning the wheel. There's a good chance that the speedo just decided to crap out after 18 years.

Stay tuned!
 

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Discussion Starter #14
SOLVED!

Ended up being a bad Speedo sensor (with nothing visibly wrong with the rotor magnet) after all. ¯\_(ツ)_/¯

Special thanks to Superdog for the wonderful '01 sensor assist, and TeeRiver for his wealth of knowledge that I used to help narrow down the possible issues.

I was über-stressed about this! Didn't want to lose my classic OEM gauges.

Cheers, gents! :eek:ccasion14:
 

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Gents, excuse me jumping in late, but this seemed more relevant than starting a new thread. Prepping my son's 2000 UK SV650 naked: he had a total short and the dealer sorted a new RR and other issues. He also sent the speedo to a repairer in the UK but we haven't seen it work successfully to guarantee it is OK. We have everything back together, working and running fine except speedo. TeeRiver, I followed your excellent tutorial (although I am super confident on mechanical parts, electronics make me twitchy) and with about 12.4v across the battery terminals i get zero in the speed sensor block from the speedo across b/w ground and red/orange, suggesting i am not doing it right OR there is no pwer from the speedo. A physical inspection at the wheel suggests the speed sensor is OK but unable to do a substitution like Kaliozone (yet). I am going to try the other tests above but I couldn't follow the wiring schema sufficiently to work out where the power goes into the speedo - is it a one to one routing, in on a colour and out on the red/orange, or more complicated? We may also go for an after market speedo but I'd like to know if the original actually works, I can't find a test in the manual/forums. Paul
 

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... He also sent the speedo to a repairer in the UK but we haven't seen it work successfully to guarantee it is OK. We have everything back together, working and running fine except speedo.
So the speedo is back on the bike, everything is connected but it is still not working?

I imagine the repair tech would have tested the unit before sending it back to you, no?
 

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It was a while back but I've asked my son to ask the repairer what he found, what and how tested.. my son moved out so it sat there a good while.
 
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