nighthawk 550 electrical problem

Mark,

My Clymer manual should be here tomorrow. Once I look at th
section referring to the rectifier I will try your fix. In th
meantime, one of my electrician friends at work asked if I had checke
the coils yet. He said that it is possible if the resistance is to
high on them they could be failing which would also impede the chargin
capacity of the bike's charging system. Have you ever heard anythin
like this before. It sure sound relevant due to how poorly the bik
runs until it runs for a minute. It does not seem that it is an issu
of warming up because even after it begins to run well it can go bac
at any moment to running poorly

 

I don't know if you understand the nature of Mark's solution to the
remote sensing wire problem or not. If the remote sensing wire is open
or has high resistance, the voltage regulating circuit in the rectifier
regulator won't work and the voltage will get too high.

That's which Mark moved his wire, he wanted to avoid burning up his
stator from HIGH voltage. Your problem so far seems to be LOW voltage.
Your stator could already be partially shorted out, but you need to do
the open circuit voltage test to see if it's putting out AC voltage at
5000 to 7000 RPM.

The rectifier regulator is a two part device which has the six diodes
that change AC from the stator into DC that the battery can use.

The voltage regulating circuit is a silicon control rectifier that
grounds out one phase of the stator when the voltage gets too high. The
silicon control rectifier is sometimes also called a "thyristor".

When the SCR grounds one phase of the stator, that cuts the AC outout
in half momentarily. The silicon control rectifier has enough built-in
resistance, when it conducts electricity to ground it just gets hot
without hurting itself.

The remote sensing wire simply sends voltage to a component called a
zener diode in the voltage regulating circuit of the rectifier
regulator. A zener diode is a kind of diode that doesn't conduct
electricity until the voltage reaches the desired level. Then the zener
diode conducts electicity to the gate of the silicon control rectifier,
telling it to
shunt the high voltage (around 15 to 16 volts) to ground.

That's why the rectifier regulator is also called a "shunt type
regulator".
It just wastes excess voltage into the frame of the motorbike.

You might have loose connectors on the ignition control module or on
the ignition coils themselves. If you want to see if you have enough
voltage to produce adequate sparks, install a fully charged battery,
remove the spark plugs and reinstall the plugs in the plastic
connectors on the end of the ignition wires and crank the engine over
while holding a spark plug about 1/4 of an inch away from the cylinder
head. If you get a bright blue spark that jumps 1/4 of an inch, you
have enough spark to rev up the engine to do your open circuit test.

If you get a weak white spark that won't jump 1/4 of an inch, or it's
orange or red, that's really weak and you'll need to figure out what
the problem is. An electronic ignition system either works or it
doesn't, the most likely problem for weak spark is dirty or loose
connectors.

If you don't have a weak spark, the most probable reason for bad
running is dirty idle mixture jets. I've described what to do about
that in this newsgroup about a bazillion times, so you can google that
information up.