The TL is a 1997/ 1998 model platform.
So we are seeing more and more confusion around proper TL operation as the
problems become more compound/ complex. I recommend you do all maintenance
if your bike runs poorly.
Basic problem areas: Air Intake System, Fuel Delivery System, Electrical
System, Vacuum System, Safety System
Air Intake System
There are a few major sensors associated with the air intake system that
feeds info to the ECU to control fuel/ air mix. The Air Pressure Sensor
which is located under the headlight and the Air Temperature Sensor located
in the airbox. If there is a problem with either of these sensors the ECU
will throw an error code. Basically for the air system to function properly
you need to keep your air filter well maintained and the airway clear.
Fuel Delivery System
The major troublesome components of this system are the fuel filter, fuel
pump, and the injectors. The fuel filter is located inside the tank and is
attached to the fuel pump. The fuel filter should be replaced every couple
years and can cause the bike to run
lean/ poor/ not at all if clogged.
The fuel pump is inside the tank and is bolted to the underside. The
major sign of failure with the fuel pump is that you don't get that whining
noise when you turn the ignition on which is the fuel pump priming. If you
expect your fuel pump is bad you should make sure your dash does not show "CHEC".
If it does then you should make sure the bike is in neutral and that the
neutral light is on. If the Neutral light is on then you will want to start
checking fuses and electrical connections or Fuel Pump Relay to the pump as these are more
likely causes than the pump itself. the fuel pump relay is often a point of
failure and should be replaced before buying a new fuel pump when
troubleshooting. You may see the proper voltage coming from the relay but
may not have enough current to get the pump going. The Fuel Pump relay is
located under the drivers seat.
Symptoms of a bad Fuel Pump relay are; the bike dies intermittently,
sometimes will not start, fuel pump does not whine when ignition is turned
on in neutral.
The injectors are located on the throttle bodies (TBs). There are four on
the TLR and two on the TLS. If they get clogged they should be replaced as
per the manual. Clogged injectors can cause the bike to run lean (see
the spark plug burn chart) or cause poor performance. Commonly in the
TLR the secondary injectors become clogged. The secondary injectors spray
above 4K RPMs (send me a note if this is incorrect) and the symptoms are
bogging above this RPM.
Another problem can occur with the injector or injector rail if there is
a vacuum leak. Look at the vacuum lines if you are troubleshooting to the
injectors. Symptoms are boggy, boggy at 4K+ RPMs, does not idle -just dies.
The electrical system is comprised of the Supply Power, Regulated Power,
Stator Power and fuses.
The supply power is generated by the battery. If the battery is not
working properly it can make the bike hard to start and run poorly. The
battery does not supply current to the bike when the bike is running and
creating its own current. However, the electrical system is a floating type
system and utilizes the battery as a capacitor after the bike is running to
help regulate and help the regulator control the current flow. If that last
sentence doesn't make any sense then just ignore it and know that a battery
with a dead cell can start your bike and appear ok but can still effect the
bikes behavior. A common problem is the battery connections are loose or
need cleaning -especially ground to the bike. The main fuse block or
Starter Relay can also
be a problem supplying current to the bike see the
power connector fix.
Regulated Power is the power that comes from the Regulator/ Rectifier
(R/R) located under the drivers seat. This powers the spark coils, dash,
fuel pump, lights and everything else electrical when the bike is running.
The R/R gets its power from the Stator Power and simply takes that power and
regulates it in two ways 1) gives out regulated power to run the electrical
on the bike 2) Recharge power to the battery. When the regulator is not
functioning there are 2 possible scenarios 1) The R/R is not providing bike
power and the bike runs off the battery only -this only last 10 minutes or
so before the bike dies from a fresh charge and will not restart due to dead
battery 2) The R/R does not provide recharge current for the battery -good
for 5 or 6 starts then will not start again until the battery has been
charged on a charger. The most likely cause is electrical connectivity.
There are numerous harness plugs in the wiring leading to the R/R see the
power connector fix
Stator power is the power generated by the engine turning. The components
here are simply a magnet and some coils of wire. Problems with the stator
are uncommon. Typically harness connections to and from the R/R are the
issue and the symptoms are; The R/R is not providing bike power and the bike
runs off the battery only -this only last 10 minutes or so before the bike
dies from a fresh charge and will not restart due to dead battery.
Fuses are located in a little black box attached to the inside of the
fairing under the throttle grip. There should be a small phillips screw
securing the access lid. There is a main fuse block under the shifter side
fairing right off the positive battery terminal. This block contains a 30A
fuse and a spare. These fuses should be checked whenever something
electrical does not function.
The vacuum system powers the Fuel Pressure Regulator (FPR) located on the
injector rail. It also powers the flapper actuators. The vacuum pressure
itself comes from ports on the throttle bodies. If a vacuum port on one of
the throttle bodies is left open it will cause them to be unbalanced and the
bike will not idle -just stall. If there is a slight leak if will cause the
bike to run rough. See
Airbox Mod and
The safety system is comprised of the clutch switch, side stand switch,
tip over switch, kill switch, Gear Position Indicator, and Airbox flappers.
Sometimes these safety components can become worn or otherwise
inoperative which may cause the bike to stop working. Symptoms are the bike
dies and/ or does not start. The dash should show "CHEC".
The clutch switch is part of the clutch lever housing. It is required
that you pull in the clutch to start the bike. If the fuel pump primes with
the ignition on but the bike does not respond to pressing the start button
then this may be your issue.
The side stand switch is attached to the side stand mount just under the
drivers shifter side foot peg. Symptoms here are the bike studders badly
over rough roads, bike will not start in gear or dies when put in gear. The
dash should show "CHEC".
Tip over switch (TOS) is a black box located under the drivers seat on
the fuel tank hinge. This may act up randomly and cause the bike to stop
functioning. The tripped safety condition is reset by turning the ignition
off then back on. Sometimes the TOS may require a couple taps to reset if
the bike was dropped on its side. Symptoms are the fuel pump will not prime
with the ignition on with the neutral light on and the kill switch set to
on. The dash should show "CHEC".
The kill Switch is the big red rocker switch right next to the throttle.
This can be faulty especially if your bike lives outdoors or you like to
ride in the rain. Symptoms are the fuel pump will not prime with the
ignition on with the neutral light on and the kill switch set to on. The
dash should show "CHEC".
The gear position indicator (GPI) is located inside the engine and tells
the ECU what gear the bike is in. If the GPI is not working at all then your
neutral light will not illuminate with your transmission in neutral and the
bike will not start with the side stand down. If the GPI is not working your
bike will run a neutral fuel/air mix map instead of running and individual
power map for each gear. This can cause a lack in performance.
Airbox flappers are located on the top of the airbox. If these flappers
are not working correctly you bike will bogg see
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