Trailtech Vapor install on WR400

8 replies to this topic
  • chickenstrips

Posted May 16, 2008 - 11:30 PM


Installed my Trailtech Vapor today, figured I would post up a few pics. I am not sure if the power wiring is good or not, when I turn the power on the RPMs freak out. Going to call Trailtech and see what they think, the bike is all stock (doesn't have an upgraded stator or capacitor or battery).

Here are the pictures and somewhat of a guide.

I wrap the wires with silicone tape, waterproof, heat resistant, sticks to itself and doesn't make a mess.

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Tach wire ran through bike

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Small slit in coil wire covering to run tach signal wire through

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Tach signal wire soldered onto coil connector

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With the rubber boot back on

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Tach signal ground, to the frame

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Power wiring (DO NOT WIRE TO HEADLIGHT, this will cause the RPMs to not function properly)

Black Connector coming from the CDI box, pull the black and green wires out (press up on small plastic tab inside connector and pull terminal out). Just wrap the red wire for the vapor around the green and the black around the black, then get the terminals back into the plug and make sure they click in place.

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Tach and Power connectors

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Trailtech Vapor unit mounted with the supplied bar clamp, works OK but I will probably order the $10 bracket that bolts to the front of the triple clamp.

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Water temp is not installed because I originally ordered the kit for my DRZ-SM, which comes with a 6mm sensor for the radiator bleed port. I need to get the hose coupling/sensor for the WR.

Speed sensor is installed and was fairly easy to do.

Here's the bike. Plated 99 WR400F. Probably ordering new plastics soon. Just put new tires on.

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  • 89TRX350RX

Posted May 17, 2008 - 06:24 AM


Nice work and thanks...


  • maxtherat

Posted May 17, 2008 - 08:19 AM

Read this. You have a couple of options that should fix your tach problem. Either re wire the tach signal wires (both) or re ground the one wire from the power supply to the chassis instead of the ground you used in the harness.

  • chickenstrips

Posted May 17, 2008 - 01:49 PM


Changed the power wiring to this:

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From this thread:

It makes the power on all the time (when the bike is running) and the RPM problem is fixed, no 18000 rpms all the time etc. I'd say thats the proper way to hook it up.

I took pictures I will put them up in a bit, have to go adjust the pilot air screw or whatever it is on the frontside of the carb. I left it closed on accident.

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  • chickenstrips

Posted May 17, 2008 - 06:29 PM


updated first post with the proper way to wire the power for the vapor

  • robert93727

Posted October 22, 2008 - 07:30 AM


Hi thanks for the post. Ive just installed a trailtech vapor on my 2000 wr400. I'm looking for the proper high temp and danger temp degrees so I can set the computer to warn me. Also looking for the oil change and tune up distances. I would appreciate any help. Thanks

  • byggd

Posted October 22, 2008 - 08:15 AM


I set mine @ 200 warning and 240 for oh crap! seems to work well on my 02.

  • anoldsman

Posted August 08, 2011 - 12:35 PM


I installed a Trailtech Vapor on a 1998 WR400F as per these instructions and I am getting around 4x the RPM with the tach setting at 1 and 2x at setting 2. Any ideas on what I did wrong?

  • USMC_CRF450_WR400

Posted October 10, 2011 - 09:57 AM


Where are you going to splice into your coolant hoses for the temperture sensor? So my real question is.....where is the cooant the hottest, coming out of the engine so the sensor picks up the hottest and most accurate reading? Nature tells me common sence would apply but i always like to ask just to be sure.


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