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Discussion Starter #1
Hi everyone, I recently changed the Tach dial on my 2003 bird, I followed a guide online to do it and all seemed fine for a day or 2. Yesterday whilst out for a ride the Tach dropped to 0 and for the rest of the day was intermittent, reading 0 for quite some time then jumping to the correct rpm before falling back down.
Any suggestions would be helpful, thanks.
 

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Is it possible the tach motor is working but the needle is loose on the motor? Never did a Bird tach so no experience.
 

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I'm planning to fiddle with rev gauge myself...curious to know what was your process for removing and reinstalling the needle?
 

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Discussion Starter #4
I'm planning to fiddle with rev gauge myself...curious to know what was your process for removing and reinstalling the needle?
I gently lifted the needle over the black post then marked its resting position. I then used 2 spoons to lever the needle off evenly. When re fitting I put the needle back in the marked position then lifted it over the post. When it works its spot on but its only working intermittently now, It was working perfectly before, so try this at your own risk.
 

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I removed my needle from the gauges carefully, two spoon technique, but I didn't mark anything. Great. LOL.
 

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But how does it matter how do you position the gauge - how can you even do it wrong when there's a physical limiter, a small needle, right under 0 rpm mark? Confused :D
 

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Discussion Starter #8
But how does it matter how do you position the gauge - how can you even do it wrong when there's a physical limiter, a small needle, right under 0 rpm mark? Confused :D
Because electronic gauges have something called preload on them. The needle has a different position depending on power on or off, I know this because the first time I put the needle back on I forgot to line it up with the mark. I just put the needle next to the post. When I turned the ignition on it jumped to 1500rpm and stayed there without the engine running. Re installing it to the mark solved that issue and it worked fine.
In other news I’ve solved the problem. Before re installing the needle I put a couple of drops of oil into the hole for the shaft. I think some of the oil may have dropped onto the windings as today I took it apart and sprayed the windings with contact cleaner. It now works perfectly and has done throughout the entire afternoon of riding. So looks like problem solved.
 

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I just disassembled my other set of gauges, from late model Bird. How would I put it back the wrong way if there's a limiter? Help me out :D



How would I position the needle in any other way other than "leaning on the limiter" at 6 oclock so to speak. You're saying I should, for example, budge the needle in at 9 oclock and twist it down to the limiter?

Because that's not the way how the needle got out. Sorry for being daft lol
 

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Tom,

What JSForder was explaining is that when the needle is in the off position (resting against the post as per your diagram) it is still under an anticlockwise pressure pushing it against the post.

So in that state, lifting it up and over the post (anticlockwise) will let it go to an unpressured location (approx marked "X" on my version of your diagram).

What he did was exactly that (and marking it) before removing the needle from the central spindle. Hence when he reattaches it, he did it at the X position before then lifting the tip up and over the post (moving it clockwise).

Untitled 1_2.png


JSForder… yes/ no to that?
 

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Discussion Starter #11
Tom,

What JSForder was explaining is that when the needle is in the off position (resting against the post as per your diagram) it is still under an anticlockwise pressure pushing it against the post.

So in that state, lifting it up and over the post (anticlockwise) will let it go to an unpressured location (approx marked "X" on my version of your diagram).

What he did was exactly that (and marking it) before removing the needle from the central spindle. Hence when he reattaches it, he did it at the X position before then lifting the tip up and over the post (moving it clockwise).

View attachment 130511

JSForder… yes/ no to that?
Exactly that and a much better explanation than mine. Thanks
 

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Thanks JSF,

I should also build on your observation that if one wrongly attatches the needle at the 0 rpm/post and switches the ignition on (or apply 12v if the gauge is off the bike) then the needle jumps to 1500 rpm and stays there despite the engine being off/ not even attached.

The distance from the post to the 1500rpm mark is therefore the same distance from the post but in the opposite direction to identify where "X" is. Useful if you didn't identify X before removing the needle. Now anyone can find X.
 

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Note for the perfectionists:

The 1500 rpm mark was where JSF says the needle went to. I'll assume not all gauges are exactly the same so someone trying to find X accurately still ought to attach at the post first. Applying 12v/ turn ignition on and see for themselves where their needle settles at (in the region of 1500rpm). That step ought to allow anyone to i.d. X exactly for each individual gauge.

Note for us pedants:
Yep that is still "give or take" needle width/ post width/ distance from post to zero (if any) and any applicable least step of your measuring instruments etc. Head hurts now… must lie down in dark room…!
 

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Ooof. So I took my spare set of gauges to the garage and tried to decipher how the needle drop works :D

Method one - just push it in on zero mark. Turn the bike on, nothing happens.
Method two - push the needle on the X mark as advised here in the thread, wind it to 0 mark counterclockwise - nothing. Same method, but wind it clockwise to 0, nothing.

I even started lightly pushing the needle around while the bike was idling just to see if it'll get some reaction. Eventually with one attempt, the needle was slowly creeping from 0 to 2000 but far away from correct behavior. I tried pushing the needle in lightly just so that it "bites" in place, and same result.

So now I have to ask, how does this work? How did they put these needles in factory on the assembly line? How do I fix this problem, I don't want to ruin my main gauge cluster with attempting to figure it out how it works. Help! :D
 

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Also, I took a pic of the cluster connector just in case I get inspired to hook it up to my bench PSU :D

I guess the wires on the connector weren't aligned in the factory as per the diagram, I presume every Bird has these cables aligned differently, as it's not crucial to reflect the diagram pattern. I tried to decipher the "top row" of the connector with the diagram.

 

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Quick update - spent some time figuring out the gauge, and I don't think the needle needs any positioning. Taking the cluster fully apart, under the needle you have a coil thing, galvanometer or whatever, and on the board printed you see the sine and cosine markings. I'm not that well versed in maths, but what other use of these markings and coils other than created a specific magnetic field in specific "area" between those 4 pins, which drags the needle via its magnet to the proper rev reading.



I hooked up dupont wires to Arduino and put 5V on the cos + / cos - pins, and the needle moves, because of that small magnetic field. So I don't think ECU or the coil cares at what direction is the needle inserted, as long as you don't push it way too down where it has way too much friction, it has to sit lightly in its place so you can move it by puffing on it. I'll test the theory tomorrow :D
 
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