How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Louie Your Own Question
Louie, Technician
Category: Motorcycle
Satisfied Customers: 12677
Experience:  25+ yrs. experience
Type Your Motorcycle Question Here...
Louie is online now
A new question is answered every 9 seconds

Cbr 600fx--started stalling on idle (with idle really high

Customer Question

cbr 600fx--started stalling on idle (with idle really high even)
JA: Is the check engine light on? Does the car stall at idle or when driving?
Customer: now wont start no spark
JA: What is the model/year of your motorcycle?
Customer: cbr 600 fx 2000
JA: Are you fixing your bike yourself? What have you tried so far?
Customer: yes u a bot?
JA: Anything else you want the mechanic to know before I connect you?
Customer: yes, the signal generator output while cranking is 1.2v AC no DC voltage manual does not specify if it should be ac or dc i suspect the signal generator is faulty & should output DC is that corect?
Submitted: 1 month ago.
Category: Motorcycle
Customer: replied 1 month ago.
carb model
Expert:  Louie replied 1 month ago.

Hi and welcome to JustAnswer, I’m Louie. Sorry you had to wait awhile but I’ll do my best to help.
Initially, have you checked the burn colors of the spark plug tips?

...attempt to start again with the side stand folded up? ...clutch lever pulled in?

And to avoid asking you to do something you've already tried, can you please tell me what / any and all troubleshooting / specific steps you've already attempted other than the above checks on the "...signal generator..."

This is an independent site and members of this online community provide information, repair tips, technical assistance as a form of paid Q & A service.

Customer: replied 1 month ago.
Hello,I have attempted your suggestions.
I have Haynes manual have tested the
Ignition HT coils
Throttle position sensorthe ignition pulse generator I have also tested & it outputs 1.2 v AC (measured with a multimeter , no peak voltage adaptor)
the manual does not specify if it should be AC or DC it only says it should be above 0.7I am not sure about the pulse generator
Should it be AC? are the ht coils powered by AC? ,Also that says should be minimum 100V on AC there is 0
on DV I get 0.00v, the as I hold the start button & as the engine spins the voltage goes up slowly to 0.078 & the drops to 0.04 & fluctuates.
Customer: replied 1 month ago.
Expert:  Louie replied 1 month ago.

To my recollection, the ignition coils would have a consistent IGN+12V on 1 of its wires


a pulsating voltage to ground on the other.

Both are DC voltage.

The pulse generator would be producing a pulse also but lower thus it would be AC in a sense.

Is your Haynes manual in electronic form?

Customer: replied 1 month ago.
no it is a book
Customer: replied 1 month ago.
38; reading it again, yes 12 volts battery input
& minimum peak 100voltsso, 0 input & 0.078 fluctuating clearly a problem
Expert:  Louie replied 1 month ago.

The pulse generator would normally produce 500mV to about 1V. And as its name implies in pulses. These pulses trigger the ignition module to drive to ground the other wires of the ignition coil. These high speed switching to ground induces high voltage at the secondary of the ignition coil = spark.

So first, we must establish the presence of these low voltage pulses from the pulse generator.

Can you post back with a picture of the wiring diagram? ...again to serve as common reference.

Bear with me for possible delays, mobile with sluggish Internet if at all.

Customer: replied 1 month ago.
as i mentioned, i do not have a peak voltage adaptor, only a multimeter & am getting 1.2v AC.As the ht coils do not have 12 v present when ignition is on (let alone a 100v pulse), does that not point to some relay or capacitor?
Expert:  Louie replied 1 month ago.

Appreciate your kind understanding; was mobile.

For some reason, the right half is missing.

Still, locate the black and black/white wires of the engine STOP switch. For test purposes, jump these 2 wires together. Attempt to start again / check for spark.