mini tach on 2008 fatboy.
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Tourer
Joined: Jul 2009
Posts: 321
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From: Carol Stream, IL
mini tach on 2008 fatboy.
has anyone installed a mini tach with shift light on a fatboy. There are 2 that HD sells but in both it says not for 2007 and later fatboy... if these cant be installed are there any other that can be installed I am thinking of putting them smack in the middle of the stock riser .. any idea if this could be done or not
any pics with mini tach installed on a fatboy would be most helpful.
any pics with mini tach installed on a fatboy would be most helpful.
May our Moderator Rest in Peace
Joined: Sep 2006
Posts: 11,386
Likes: 35
From: Rochester, NY
I never understood why I wasn't supposed to be able to hook one up on my 07 Custom either. So I put one on anyway and it works just fine.
It wasn't until later that I realized that the reason I got it to work is because I 'didn't' follow the directions that tell you to hook it up to a pin in the back of the speedo.
If I had followed the instructions that came with the tach it probably would have given false readings or not worked at all because the speedo on the 07's (and up) is run off the EMC with a kind of serial data line. So all the speedo's idiot lights, and needle don't have any real dedicated lines. But are told what to do with data instructions from the computer in the ECM.
A normal tach (like the ones Harley sells) looks for a continuously pulsing line signal, not an ascii data command. So you 'can't' hook it up the same way.
I'm convinced that I got mine to work more by accident than design. I didn't like the idea of using a line that wasn't 'full time'. So I looked through the wiring diagrams and found that pin 3 of the ECM is actually a full time tach output line and is not normally used, so I found the right kind of pin and installed a new wire from there to the tach.
So you can hook one up, you just have to do it a little different.
It wasn't until later that I realized that the reason I got it to work is because I 'didn't' follow the directions that tell you to hook it up to a pin in the back of the speedo.
If I had followed the instructions that came with the tach it probably would have given false readings or not worked at all because the speedo on the 07's (and up) is run off the EMC with a kind of serial data line. So all the speedo's idiot lights, and needle don't have any real dedicated lines. But are told what to do with data instructions from the computer in the ECM.
A normal tach (like the ones Harley sells) looks for a continuously pulsing line signal, not an ascii data command. So you 'can't' hook it up the same way.
I'm convinced that I got mine to work more by accident than design. I didn't like the idea of using a line that wasn't 'full time'. So I looked through the wiring diagrams and found that pin 3 of the ECM is actually a full time tach output line and is not normally used, so I found the right kind of pin and installed a new wire from there to the tach.
So you can hook one up, you just have to do it a little different.
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