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Strange tach function


Warp11XX

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Anyone got any ideas on this little anomaly? Started the bike this morning normally for the commute to work. Nice docile coast down the mountain through my neighborhood as she warmed up. I pulled out on the highway, ran the rpms up a bit, nice smooth shift to second, nice smooth shift to third, glanced down at the gauges to confirm all was right with the world, noticed my rpms were at about 9000 and climbing briskly. This might sound reasonable, if I was actually doing about 115 mph, but I was actually just passing a very sedate 38 or 39 mph. I focused on the tach for a few minutes...drop to idle indicated at 2000 rpm...uh-uh...approximately 60 mph indicated a blistering 9500 rpm in sixth gear. WTF, over? :icon_rolleyes: As I coasted through another residential area, I shifted to neutral, turned the key to the off position, turned it back on and restarted the engine....everything went back to "normal" state...idle is 1000 rpm, cruise at 70 in sixth gear is 4000 rpm...normal. What is my pretty little vixen doing to me? Seemed fine at lunch today going across town...

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Thanks guys! With that said... :icon_rolleyes: FUCK, FUCKITY, FUCK, FUCK ! The stator got replaced under warranty less than 5K miles and 2 years ago(and they scratched my stator cover at the same time...bastids). I suspected something wasn't totally right since the technician "slipped" and told me that he was a bit baffled because IIRC the AC output was only about 48 to 50 VAC on each phase. I asked him if that was normal...? His response was that it was consistantly making 14 VDC, so all must be right with the world. Now I get to fix it correctly out of my pocket. Fuckin stealerships... :icon_angryflip:

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can't help with the electrical gremlins but carbon fiber engine armor covers the scratches nicely, and looks pretty as well. :icon_whistle:

After getting a close look at Racer212's bluebird last weekend, I'm inclined to go the opposite direction. Polished engine covers look SCHWEET !

Sooooo... :icon_rolleyes: after testing and checking main connections last night, I'm wondering/hoping/praying that it was just a case of the battery being down a bit after sitting for a couple months....??? :icon_rolleyes: Maybe? Hopefully? Wishfully?

I had 12.56 VDC at idle. 2000 rpm raised the average ouput to 13.92 VDC. 5000 rpm steady state brought it to a peak output of 14.52 VDC. Turning on hi beam HID, a signal, heated grips, and squeezing the brake (all LED brake light with flasher) gave me a "loaded" voltage drop to average of 14.20 VDC. I still need to pull the rear cowl and check all the R/R connections and condition. Would a funky and temporarily low battery voltage lead to the tach doing this oddball dance? Did it heal itself of a minor/fluke little sniffle?

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I'd get a bit suspicious of a supposedly fully charged battery that registers (at rest or idle) less than 12.8v without any load... The readings at 2000/5000 suggest to me that the alt and R/R are working as intended. How old is the battery, and was it fully bench charged before installation..?

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I truly believe the 'bird heals itself.

Mine did just the opposite. I was riding down the highway and it dropped to zero. Then worked. Then dropped to zero. Then worked. That led me to check the battery and wiring. That is when I found my toasted connection between the R/R and the stator. I got that fixed and all voltages were good. Then my tach started to work, then not for about a week. Then it would stay at zero when I started the bike and start working about a mile down the road. Within the last week it works fine. Registers right at start up and works fully.

Hell if I know what it was.

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I'd get a bit suspicious of a supposedly fully charged battery that registers (at rest or idle) less than 12.8v without any load... The readings at 2000/5000 suggest to me that the alt and R/R are working as intended. How old is the battery, and was it fully bench charged before installation..?

Second year I've had the battery. It's a 14 amp Diehard gold that was dead in spring, recharged, left sitting two more months, and then irritated into starting yesterday morning. I certainly haven't been real nice to it now that I think about it... :icon_whistle:

My initial check was 12.8 or so while not switched on. I'm really hoping this was just a large load that drew down the system momentarily.

I truly believe the 'bird heals itself.

Mine did just the opposite. I was riding down the highway and it dropped to zero. Then worked. Then dropped to zero. Then worked. That led me to check the battery and wiring. That is when I found my toasted connection between the R/R and the stator. I got that fixed and all voltages were good. Then my tach started to work, then not for about a week. Then it would stay at zero when I started the bike and start working about a mile down the road. Within the last week it works fine. Registers right at start up and works fully.

Hell if I know what it was.

That would drive me nutz... :icon_wall:

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Now I'm even more suspicious of the battery... A new battery (properly bench charged, per instructions/rate found on sticker on battery top, prior to installation) may be your best - and cheapest - bet. At least it'd be one issue you'd know was right if the problem persists; and, it'd be the best baseline for further electrical testing (gremlin hunting).

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