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I posted on here a couple months ago about my bike not reading tach. i was told to check the gauge cluster to see if it was plugged in, ive tried 2 different ones and neither of them read. it started after i laid it down on hits left side (shifter side). was wondering if any one has any other idea's, thanks.
 

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How about checking the fuse , relay under left side ram air cover
 

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How about checking the fuse , relay under left side ram air cover
if the fuse goes bad the gauges wont function at all not just tach. i am currently suffering the same issue after sending my gauges off to get color changed.
 

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Who did you send them to?
I prefer not to say who i sent them to. because i dont believe it is relevant to why my tach isnt working. If you wanted to know who because you wanna do the same thing i would be very happy to let you know via PM i can send pics they came out very well did white displays white numbers red needle. I do not believe it is in the gauges the initial sweep is fine and the rpm sets to zero and stays there no ticking or shaking at all i think my issue is with a wire coming undone during removal or but not very likely yet possible the sender prior to ECU not 100% yet but this is where i will start after some thought. if it where ecu and after i would think the initial sweep would not function and if a loose wire i would get momentary readings. i tried hooking a meter to the wire i believe is the tach wire but i didnt get a reading from it with the bike runnning. i was thinking about just revving it to see if the limiter kicked in which i would think is a good sign the ecu was getting a signal but then if it doesnt whats gonna keep me from over revving :( so i opted not to do that.:icon_pai:
as there was dissasembly required to get the gauges out im thinking i may have pulled a wire somewhere that i was oblivious about. i plugged the gauges in one shot no issues with connecting the wrong way power was off. so im pretty sure i didnt burn anything out.
I rode the bike a few weeks with no gauges i dont think that would be the problem since i have read from a few people that they rode without theirs.
 

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There's a pretty good section in the workshop manual for fault finding a tacho that doesn't work.

If the bike runs OK it's not the sensor in the motor as this is used to determine all the ignition firing etc. More likely an issue with the signal from the ecu to the gauge - as I jus t posted elsewhere I've known this fault to be a faulty ecu (was a HRC one but the circuit is identical) especially as you're getting the right power to the gauge shown by the initial sweep working.
 

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There's a pretty good section in the workshop manual for fault finding a tacho that doesn't work.

If the bike runs OK it's not the sensor in the motor as this is used to determine all the ignition firing etc. More likely an issue with the signal from the ecu to the gauge - as I jus t posted elsewhere I've known this fault to be a faulty ecu (was a HRC one but the circuit is identical) especially as you're getting the right power to the gauge shown by the initial sweep working.

I have noticed that when i let off the throttle from a decent rpm say maybe around 5k i get a backfire dont remeber that happening before unless i was up around 10k plus. dont think this is what you ment by if your bikes running OK. i know if the firing was messed up i would be getting backfires and the works or maybe nothing at all but this is what i got :( also due to the curious george in me i pinned it in first gear till i hit 73 mph. which is a good sign the rev limitter isnt working ( normally 66 mph )prolly cause the ecu isnt getting a signal. im gonna tear my bike apart tonight and look for a disconnected wire. if anyone can tell me where on the motor exactly to look for the wire that carries the rpm signal to the ecu i would greatly appretiate it i dont own a workshop manual... yet. but i will be ordering one and dont have the patience to wait :) . but i also dont want to do a complete tear down the night before i goto work if i can avoid it.
 

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well after more internet reading and a voltage check seems my ecm is sending 9.4V instead of 10.5V min. :puke:

says if signal is under 10.5V to replace ECM. Well that sounds easy. Just gonna go pick a few dollars off the tree growing in my back yard /cry
 

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You can get a used ECM for around 30 bucks shipped mine went bad for some unknown reason.The brand new prices are anywhere from 600 to 800.
 

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There's a pretty good section in the workshop manual for fault finding a tacho that doesn't work.

If the bike runs OK it's not the sensor in the motor as this is used to determine all the ignition firing etc. More likely an issue with the signal from the ecu to the gauge - as I jus t posted elsewhere I've known this fault to be a faulty ecu (was a HRC one but the circuit is identical) especially as you're getting the right power to the gauge shown by the initial sweep working.
Troy45 Thank you for the input. :) as i posted earlier i did do a voltage check on the ecu to the gauges and it seems as though you are absolutely correct the ecu signal is week. for those that have a tach not working but everything else seems to be fine i would check the voltage /yellow and green wire + / green wire neg. for the 03 not sure which wires on other models but possiblly the same color. rather than checking the gauges first so i wouldnt have to tear the whole bike apart to get to the plug on gauges. i used the back of the connector located under the left side cover located under handlebar not sure of pieces name ( as your sitting on the bike ). the manual i downloaded says if the signal is below 10.5V to replace ECM. :( i get the new ECM on the 16th 89$ high bid on ebay claims its new. after i install it I will post updated info.
 

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Troy45 Thank you for the input. :) as i posted earlier i did do a voltage check on the ecu to the gauges and it seems as though you are absolutely correct the ecu signal is week. for those that have a tach not working but everything else seems to be fine i would check the voltage /yellow and green wire + / green wire neg. for the 03 not sure which wires on other models but possiblly the same color. rather than checking the gauges first so i wouldnt have to tear the whole bike apart to get to the plug on gauges. i used the back of the connector located under the left side cover located under handlebar not sure of pieces name ( as your sitting on the bike ). the manual i downloaded says if the signal is below 10.5V to replace ECM. :( i get the new ECM on the 16th 89$ high bid on ebay claims its new. after i install it I will post updated info.
Lost access to my old user account MiamiRR but guess what.... new ecm from ebay = still not working...

Sensor/s to ECM: does anyone know for certain what signal or signals the ECM uses to generate the signal to the tach. also what type and/or range are the signals to the ECM?

From ECM to Gauges: At idle i show 9.4v it should be 10.5v but after swapping the ECM with what appears to have been a new ECM i am still getting the same voltage. ( is this supposed to be a pulse? am i using the wrong tool to check the line? )

I have opened up the gauge and checked the soldering on the 4 pins for the motor and they appear to be good ( resistance measured between bottom pair and top pair shows 335 and from soder to board 0 ). but now im wondering is the tach motor orientated correctly on the circuit board? does anyone have or is able to do a drawing for the circuit board to test the tach motor?

the only issue i have is the needle is not showing the rpm... tach does do the intial sweep, rev limiter works, bike runs strong, all lights work.
 

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I may have finally fixxed the tach

after opening up the tach here at work with an electrical guru, we found that the 3 leds used for the needle are wired wrong. they are wired to pin 3 (tach) and 8 (ign +12) should be pins 4 (ground) and 8 (ign +12). i will take this home tonight and give it a go.

brain fart while re-soldering the wires ended up doing pin 4 (ground) and pin 7 (backlight +12)
woot! straight to the garage and... it werks !
needle reading 3k at idle so I reset the needle to 1100 @ idle hits rev limiter just past 15k. perfecto
the recolor looks so much better when the needle moves.. now to do the LCD reverse color.
Thank you to all the helpful members that tossed me info. I gave up on it a few years ago then suddenly it was ever so important to have working again.
 
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