Adding lights to a YZ450FX

[yz426rdr]

Just picked up a YZ450FX. Curious about the possibility of hooking up lights. Does the full stator capacity go to charging the battery or is there a separate lead in the wiring harness for hooking up a light on AC power? I would like to power my 8" HID off the battery but curious if anyone has tried it yet.

[yz426rdr]

Nobody? I guess I'll experiment!!!

[DanielMerrick]

Nobody? I guess I'll experiment!!!

There's a thread about installing a led bar on a 14 yz450f, it's a little different but you should Have more possibility with the x

[cowboyona426]

Odds are there is a connector somewhere behind the number plate to connect your light to.

[grayracer513]

There may or may not be, but nothing on the motorcycle runs on AC power.  Alternator output goes directly to the rectifier/regulator, and there is roughly 40 watts of surplus power available. 

[yz426rdr]

This is my first bike that isn't a full motocross bike.  Not an electrical expert but I was under the assumption that on a bike like the WR that already has a headlight that the stock wiring runs from the stator in two circuits, one for running the bike and one for lights.  Also under the assumption that the light lead is only regulated and is not converted to DC with the rectifier.  That' why you couldn't wire an HID to the stock light wiring and you had to float the grount and get all power to the battery and run it directly off of the battery.  Wasn't sure it the wiring is more YZ based or WR based.

 

I didn't see a lead for a light behind the number plate.  If all power runs to the regulator/rectifier, then I'm assuming that there won't be a lead.

[cowboyona426]

There may or may not be, but nothing on the motorcycle runs on AC power.  Alternator output goes directly to the rectifier/regulator, and there is roughly 40 watts of surplus power available. 

 

I have no idea how the YZ or the FX is setup, but since a lot of us that ride snow bikes look to add lights to MX bikes I know many of them are capable of doing so.  My 2012 KX can power a light or other accessories using the connector that the dealership diagnostic computer connects to behind the number plate.  I'm assuming there must be something similar on the Yamaha's.

[grayracer513]

All three model classes of the EFI Yamaha thumpers have the same basic electrical layout.  Obviously the WR and FX have a lot of extra stuff the YZ doesn't, but the core of the system is then same.  Alternator output goes directly to the rectifier/reg, and everything in the system feeds off of DC power from the red wired circuit that comes from the DC output side of that.  There are a couple of commercially available plug-in adapters that will allow you to quickly tap into the DC+ side, and HID's actually run on DC anyway.  Most of them have a built-in ballast that rectifies AC if present.  The only question is whether there is an adequate power surplus to handle the thing.

 

LED's are one thing, but the start-up current required for HID's would mandate having a switch to power them up with, as naving them connected full time could prevent the fuel pump from getting enough juice to start the engine.  The light may only need 30-35w to run, but they can take three times that to ignite them.

[cowboyona426]

There are a couple of commercially available plug-in adapters that will allow you to quickly tap into the DC+ side

 

I don't suppose I could get a company name or a link?

[grayracer513]

Try Baja Designs or Trail Tech

[mdr219]

Fx = 160 watts DC

Yz = 85 watts DC

 

Lots of juice for a led light kit like Baja Designs Squadron

[grayracer513]

Fx = 160 watts DC

Yz = 85 watts DC

 

Lots of juice for a led light kit like Baja Designs Squadron

 

Alright then, the 40w surplus figure was for a YZ, as it turns out, so that means the basic system needs are roughly 45 watts.  That should give the FX a 115w surplus. 

[yz426rdr]

And that goes back to my original question. A bike with 160 watts of stator power usually has separate circuits for lights unless modified. It would be awesome if all 160 watts was going towards running the bike and charging the battery from one circuit off the stator. But I'm guessing the WR has a separate circuit for lights using the same stator.

[drtrcr400]

And that goes back to my original question. A bike with 160 watts of stator power usually has separate circuits for lights unless modified. It would be awesome if all 160 watts was going towards running the bike and charging the battery from one circuit off the stator. But I'm guessing the WR has a separate circuit for lights using the same stator.

Your bike should have come with a wiring diagram in the service manual. It would be really easy to figure out by taking a look at the stator.

[FORMA MOTO]

The stator is AC only.

 

Plenty of kits out there for adding lights to a stock stator.

Edited April 7, 2016 by KRANNIE

[grayracer513]

The stator is NEVER DC.  It's an alternator, producing alternating current.  That current is routed directly to a full wave rectifier that converts it to DC.  Everything that taps into the system for power taps into the DC side.  Much simpler and more contemporary.

 

Without seeing a schematic for the current WR, I couldn't tell you whether the headlamp runs on AC or not, but there's no reason it should. 

[yz426rdr]

Hey guys, first of all thanks for the input.

 

Don't know why I couldn't find it the night before but last night found the wiring diagram in the manual.  Greyracer is right in that it shows all stator output going to the regulator/rectifier.  In the charging system, there is a main fuse, a diode, the starter relay and the battery.  Not the best at reading wiring diagrams but looks like I should be able to run lights right off the battery with no fear of killing it.  The local shop mechanic where I bought it from assumed that it still had the capacitor in the system that the YZ has so it should run without the battery anyhow so worst case scenario is that I kill the battery and the lights go out.

 

Can't wait to get this thing out on the trails, track and in the dark!!!  Possibly on the road too!!!

[MidlifeCrisisGuy]

email from me to Yamaha on this topic.

 

Adding a light to a YZ250FX ?

 

Hi.

Do you know of a service bulletin that explains where one should tap into the harness on the YZ250FX in order to add a headlight ?  Does Yamaha sell a kit (pigtail with connector) for doing this ? 
 

Also, what is the maximum amount of power that one can pull from the electrical system.

 

I've asked at dealers, but they don't have a clue.
 

Thanks

 

Their reply.

 

I am very sorry however we cannot recommend to modify your unit.  

 

Edited April 15, 2016 by MidlifeCrisisGuy

[Not sponsored]

I wired stock wr head tail/brake lights to the battery by modifying an old baja designs harness that I had.

[grayracer513]

DC 12v+ is available from any red wire in the harness.  Most of the wiring should be 18 gauge or larger, and a piece of 18 gauge 3 feet long will handle up to 240 watts (40 amps) at 12 volts.  A 6 foot run will handle 144 watts.  Consider the entire length from source to load as you select which wire.  The Baja Designs (?) adapter plugs into the harness connector for the GYT-R tuner on the YZ-F.