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Discussion Starter #1
Recently, my expensive Cobra tach went bad, not returning to zero when I shut down the motor, but rather stopping at 500 to 1000 rpm, also adding that amount to my actual rpm when the bike was running. Cobra tech support told me it was a sealed unit, so no adjustment could be made. Faced with wanting to replace with a lower priced alternative, I started spinning my wheels as others on this forum have done. I bought a brand x tach on ebay, only to find that it would measure only the rear coil if I hooked it up to the "tachometer" wire in the headlight box, or would either bounce around erratically or not run at all if I ran a wire to the front coil and used an old T-101 or a Baron or a homemade connector solution. So I put the tach and Baron connector up for sale on ebay and looked around for an electronic tach that supposedly was "universal." What I ended up with is a Koso DL digital tach, coolant temp and clock, all in one. The cost on Bikebandit.com was about $150 for the tach and an additional $35 for the coolant temp adapter that goes into the hose. Being an AMA member, I received a 10% discount, so I paid about $167 total. When I installed it, I eventually learned that the the rpm wire won't work when connected to the yellow "tach" wire in the headlight box. Instead, for us VTX1800 people, it needs to connect to the camshaft position sensor, i.e. the gray wire coming out of the ECM. This info is not in the directions and took a long time working with Koso support to get it right. I'm posting it here to give anyone interested in this alternative tach solution, an easy, pain free installation process.
 

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Discussion Starter #2
Final notes on the Koso DL tachometer...

I got the coolant hose insert and installed it yesterday, and put the bike back together. After road testing it today, my final judgment on the Koso gauge is that it's not bad, but not great either. It looks good in my garage and in early morning, evening or nighttime. But it suffers from the same problem as my GPS and my LED boat instruments in that it's a little difficult to read in the noonday sun. It's readable, but the numbers don't exactly jump out at you. Nevertheless, it's nice to have a better idea of my coolant temperature, than just an "overheat" light.
 

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+1 on the Veypor. Works great, pretty easy install and even has a fuel gauge.
More of a fuel guesser but yes a very versatile device.
 

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Discussion Starter #6
In my experimentation with tachometers, I found that one can get good readings from any tach and without use of special adapters, if the rpm reading is taken from the cam position sensor instead of from the coils. On my 2003 VTX1800C, this happens to be the grey wire entering the ECM from the sensor. I simply tapped into this wire right near the ECM, ran the new wire up to the headlight bucket, and soldered it to the appropriate tach wire. I recognize that this information would probably have been of greater value back in 2003, but I've only owned the bike for a couple years and only started experimenting recently, when my (expensive) Cobra tach stopped working.
 
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