Vapor tach...

[wvu101]

I installed a trailtech vapor on my '07 gs and have been riding with the wire wrapped around my spark plug wire.  Obviously the tach is jumping like crazy but it is fairly accurate in providing me with a range the rpms are in, i go by feel mostly anyway.  Now to the point, I did the research and read to hook the red tach wire from the vapor into the black/yellow wire on the right hand coil.  I did this and my tach is reading worse than before.  It does okay at idle (still jumpy) but as soon as I rev it the rpm reading drops to zero usually until I let go of the throttle and then it spikes past 15000.  I've tried splicing it, double spading it, just wrapping it around the black/yellow lead from the coil, all leading to the same result.  Any suggestions??

[Lukewarm Wilson]

not sure yet, I have to wire mine up but what measurment did you get for the front tyre?

[wvu101]

Mine came out to 1958.  I just kept the original speedo attached and ran them together until they matched up.  They were mph for mph up to 85, I figured if the vapor is off a little bit after that I would be getting a ticket anyway .

[jeremy_nash]

yep, I know reviving an old thread......... yada yada yada  I'm a stoopid noob  
now that we're past that, what did the O P do to resolve this problem, as I'm having the same problem.  I saw somwthing about a resistorized tach lead for the vapor, but I dont have that, so does anyone have a workaround for that, or know the value of the resistor I need?

[dohabee]

I bought a veypor (not a trail tech) but I had similar rpm errors.

I had a resistor thingy that supposedly worked directly from the spark plugs but it didn't.

I tried all of the coil wires and only one worked properly.

i have a 2002 gs and I used the white wire on the left coil (left from the riders perspective) and everything works now.

not sure how similar our units are but its worth a shot if you haven't tried that wire yet.

[waiho]

you need this wire that has a resistor http://www.trailtech.net/7000-1020.html

plug into the yellow black wire from the coil

that what I have, and no jumpy rpm

[jeremy_nash]

I have it installed the same way as the 05 gauge cluster with the electric tach, it worked great as the signal for it.  I already have a cable, and would rather buy a 25 cent resistor from radio shack, than a $15 cable that may not fix my problem.  I was hoping maybe someone would maybe know the resistance of that resistor in the tach lead that waiho directed me to.

gues its time to call tech support   

[mitch.lax]

Hey guys

Jeremy, did you find out what resistance value we need?

My vapour is still jumping around slightly.

[jeremy_nash]

no, I fixed it without a resistor.  I ran my power and ground wires to the battery and it fixed the problem.  it seems to read high at idle, but it seems accurate when riding it, so that is good enough for me