The Yamaha TT-R125, TT-R125L and TT-R125LE do not come with lights and some
do not even come with wound stator coils to power lights. For the ones with
no wound lighting coils, modification is required. If you are mechanically inclined
or have wound stators in the past, then you already know what needs to be done.
If not, you can send your stator out to one of the many stator rewinding shops
or just purchase a new or rebuilt stator that has its lighting coils already
wound. The picture to the right shows the stock TT-R125L stator with only the
ignition coil or poll wound.
The engine must be somewhat disassembled to remove the stator. Before beginning
any of the following work, it is advised to purchase and use a good service
manual. On the Yamaha TT-R, you must first drain the crankcase oil because the
stator resides in crankcase oil. After draining the oil, pull the left-side
engine cover off. You will notice by the photos above and to the left, that
the TT-R stator is not behind the flywheel like many bikes. It is actually mounted
to the backside of the left engine cover and sets into the flywheel when the
cover is bolted onto the engine.
Contact or electrical cleaner works good for cleaning oil off the stator.
Package it up for shipping if you are having someone else do the rewinding.
You may also want to order a new left engine cover gasket and voltage regulator
at this time. The voltage regulator is the square thing shown in the picture
to the left. The picture also shows the newly wound stator coils with the addition
of a yellow wire that is common on most dirt bikes.
I wanted the plastic of the new headlight to match the blue plastic of the
original Yamaha plastic color. After some checking around, I purchased the Acerbis
HP headlight and taillight assembly. I went to a boating supply store and purchased
marine-grade wire, heat-shrink tubing, connectors, and a 2-1/2" stainless
steel bolt, washers and locknut for mounting the voltage regulator. I bolted
the voltage regulator to an existing hole on the right-side of the frame under
the gas tank, as you can see in the picture to the left. I removed the CDI unit
to facilitate easy installation. I made sure all ground connections were on
clean bare metal. I used the left side mounting of the ignition coil because
it already had ground wires going to it from the factory.
I wired four female power connectors into a red wire to plug the high-beam,
low-beam, taillight, and brake lights into (all separately). I soldered all
wires into the connectors for durability. The red wire just connects to the
yellow wire coming from the newly wound stator. I used plastic zip-ties to hold
everything in place, just like factory.
Notice the two forward-most red wire connectors in the picture to the left.
I have intentionally left these where they are accessible when the bike is reassembled.
This allows separate connection of the high and low beams in the headlight while
I figure out what works best (i.e. high beam, low beam or both).
The Acerbis HP headlight kit requires you to make your own wiring plug for
the back of the headlight, but they do give you the metal connectors to solder
or crimp on the wires and a plastic plug to snap them into. Again, I soldered
all connections for durability. I also used a piece of heat-shrink tubing to
group the 3 wires and run them down under the gas tank. [You may want to find
other tubing to use for a loom as heat shrink may eventually shrink down over
time from the heat rising up from the motor.] This helps reduce stress on the
wires when turning. If you use heat-shrink tubing, do not heat and shrink it
because it will be too rigid.
The Acerbis HP headlight is smaller than I expected but a good size for the
TT-R125L. It cost a bit more than others but it is DOT approved and can use
standard light bulbs (Sylvania 9003 or equivalent) found at places like Wal-Mart
for $7.00 and available in several wattages. Note: Baja Designs will try to
sell you the same bulbs for twice as much money. I ended up putting in a Sylvania
Blue-White Halogen 65/45-watt bulb. I am trying it with both high and low beams
wired up to run together (Baja Designs said this was fine) for an incredible
110 watts [estimated] of woods-illuminating power! Update, both beams on is
the best configuration.
It was a real chore mounting the Acerbis HP headlight so it would not interfere
with the front brake line. I also had to trim some plastic from the headlight
bezel to keep it from hitting against the gas tank shrouds in tight turns. The
modification shown in the picture to the left was required to keep the headlight
bezel from touching the brake line. I just drilled a hole in the headlight bezel
and zip-tied it to the handlebar so it would not contact with the brake line.
The choke is a little harder to reach but doable. [An alternate to this might
be to find a headlight with a fascia that does not interfere with the brake
line as much. It is not that critical if the brake line touches or rubs slightly
on the headlight fascia. You would also be able to run the all-important handlebar
The picture to the right is a close-up of the headlight fairing showing the
corner I had to cut away with a Dremel tool (on each side) to keep the headlight
fairing from hitting the shrouds in tight turns. Not that apparent in this picture
but on 3rd picture from top of this page is clear vinyl tubing around each fork
tube that Baja Designs sold me to make the Acerbis headlight fit the small TT-R
forks better. The rubber straps that hold the headlight to the forks were optional.
I used two zip-ties, one around each fork, to aim the headlight downward and
to position it left-to-right. Each zip-tie went through a hole in the middle
of the plastic rim under the headlight lens. [Some headlights have adjustable
beams so this mod may not apply.]
Taillight: I opted to use the Acerbis DOT approved taillight
assembly shown in the picture to the left. It is has a large mounting area for
a license plate and the taillight puts out a small amount of white light underneath
to illuminate a license plate. The Acerbis taillight assembly came with stainless
steel hex-head (Allen) hardware. [The way this taillight assembly mounts to
the rear fender actually strengthens it. If you do not go with this particular
taillight, try to find something similar that will help to strengthen the rear
fender. The TT-R rear fender (and most others) will not support a taillight
assembly if its just hanging off the end of the fender.]
The headlight on the right in the picture to the right shows that there is
not a lot of power when the engine is at idle, but who rides their dirt bike
with the engine at idle? When the engine is revved up just a little bit, the
headlight on the left in the picture shows what the new Acerbis HP headlight
looks like with my newly wound stator. Again, this is with both high beam and
low beam wired together.
Total cost of project was $330 and breaks down as follows: Stator rewind $135,
OEM left engine cover gasket $5, Acerbis HP headlight assembly $90, Extra light
bulbs (2) $15, Headlight mounting straps (4) $20, Acerbis taillight assembly
$40, Rear brake light switch & bracket $15, and marine grade wire &
I could have spent less by not getting the rear brake light switch. I could
have spent more and got a Hi-Lo or On-Off switch for the headlight too. It all
depends on what you want to do. If you want the bike totally street legal, you
will probably need these parts, otherwise I would say they are optional. I also
did not go with a horn or turn signals and I hear a horn requires a real motorcycle
battery to actually sound right. I was just trying to keep my modification simple.
Baja Designs' official TT-R125L dual-sport conversion kit with turn signals,
horn, switches, etc. runs $400 plus another $100 for the stator rewind.
Credits: TTR125 Lights Install article written and submitted by Tom Rogers.
Edited and published by 4Strokes.com.