+1 for the new Smiths Electronic Gauges

Fast Eddie

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Went on a 120 mile ride today - the Speedo was resetting constantly - needle to max/back to zero - while riding but pretty much ONLY above 4000RPM/top gear. It would do this 4-5 times in a minute. Didn't seem to do it at all at lower speeds. I'm assuming it is an intermittent electrical connection so I'll be checking that out but seems odd that it only occurred at higher RPM and not related to bike vibration. Anyway...I was missing my OEM speedometer which worked fine. Also, the digital tripmeter on the E-Smiths is very difficult to read in the sun where the stocker was no problem at all! Ain't upgrading wonderful? ;)
If it’s revs related Mike then my thoughts would be on either vibration related or interference from the ign system...
 
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Thanks, FE, I started thinking the same thing. I couldn't duplicate it on the center stand, only under load at higher RPM, where the ignition would be working the hardest. It also seemed to occur regardless of road vibration - smooth/rough made no difference.

There was a resister included for the tach, to be used if a TrisPark was fitted (it is). But I tried everything out on the center stand when I installed the E-smiths and didn't seem to need the resistor because the tach worked fine. The Tach is OK regardless of load/RPM but maybe there is electronic interference from the TriSpark/no resistor which affects the speedo. I installed the resistor this morning but can't road test the bike until I get/make new cush rubbers for the rear wheel.
 

Fast Eddie

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Perhaps also ensure you’ve not got HT leads cable tied to the speedo feed?

You have suppressed leads or caps?
 
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The HT leads are not close to the speedo feed wire.

They are suppressed wires - Taylor Spiro Pro 8mm silicone.

Heck, maybe it really is just a bad connection but everything looks fine and I can't make the speedo reset by wiggling any of the associated connections.
 

Tornado

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How's your rectifier and/or Zener? Perhaps you're getting over volts DC at higher rpm or AC leakage?
 
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Thanks, FE, I started thinking the same thing. I couldn't duplicate it on the center stand, only under load at higher RPM, where the ignition would be working the hardest. It also seemed to occur regardless of road vibration - smooth/rough made no difference.

There was a resister included for the tach, to be used if a TrisPark was fitted (it is). But I tried everything out on the center stand when I installed the E-smiths and didn't seem to need the resistor because the tach worked fine. The Tach is OK regardless of load/RPM but maybe there is electronic interference from the TriSpark/no resistor which affects the speedo. I installed the resistor this morning but can't road test the bike until I get/make new cush rubbers for the rear wheel.
Have you now found what the problem was?
 
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Nope - still doing it. The charge voltage is within specs at any operating RPM and, as I said, the RPM itself doesn't seem to be the issue, it only occurs under heavy load - acceleration - at approx 4000RPM +. My next attempt will be to replace the run of wire from the sensor to the speedo with shielded cable. That should eliminate any interference, if that's what's causing it.

HMMM... just reading what I wrote - "under heavy load" - wonder if it's an LOW VOLTAGE problem to the speedo in that condition? Though I would have thought that the ignition would react (cut out) at low voltage before the speedo would. But seems like the red charge light would illuminate if there was low voltage.
 

Tornado

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Wire up a temporary multimeter and monitor volts while running at the problem rpm?
 
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