Honda CX 500 Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
37 Posts
Discussion Starter #1
The bike's been running beautifully. I hopped on it yesterday to run to the store and about a mile into the ride, the bike sputtered out. The engine started cutting out like I wasn't giving it enough throttle, then it died. I noticed I hadn't turned on the petcock, so I flipped it to reserve and tried to fire the bike back up. Nada. Pressing the starter does nothing. I let it sit. Nada. Moved the petcock to the on position. Nada. Waited. Nada. Checked my tank, PLENTY of gas. Pushed it home (uphill, of course).

I'm thinking the petcock is a red herring. I'm sure lack of gas is what caused the engine to die, but I don't think it's related to the bike not starting.

I don't know where to even begin. The battery's fine. Lights work. Horn works. Plenty of voltage. Anybody ever have this happen to them?
 

·
Registered
Joined
·
2,657 Posts
It's possible that when you flipped to reserve you pulled some crud from the bottom of the tank into the carbs. Did you check to see if it has spark? Vent on the gas cap? You just have to methodically start ruling things out until you find the culprit.
 

·
Super Moderator
Joined
·
15,454 Posts
Pressing the starter does nothing.<< The battery's fine. Lights work. Horn works. Plenty of voltage. Anybody ever have this happen to them?
I think this is the key.
Silly question: Was the transmission in neutral and/or the clutch lever pulled (disengaged) when you were trying to start it? The circuit that triggers the solenoid has protections against starting the engine when in gear unless the clutch is disengaged because that would make the bike begin to move instantly. (We've all done stuff like that when flustered.)
Also, do you hear a click from the solenoid (mounted near the battery on most bikes) when you press the Start button?

Assuming it wasn't in gear, I would have looked for a place where I could roll it downhill and see if it would bump start. If it started you would know that the problem was in the circuit that powers the starter solenoid and you wouldn't have had to push it home....

The problem could be in your starter motor, solenoid, Start button or in the wires & cables that connect them together and the connection points. A quick test to see if the problem is the starter motor is to use a jumper cable or something else capable of handling lots of current between the battery's positive terminal and the terminal on the starter motor (be careful not to let it touch the bike's frame) and see if it cranks. If it does the starter motor is OK, if not you have probably found the problem.

After that get out your voltmeter and go through the steps below until you find the problem
The starter system actually consists of two circuits, the starter motor circuit and the starter solenoid circuit.

The starter motor circuit is usually a heavy wire from the + terminal of the battery to a stud on the solenoid, another heavy wire from the other stud on the solenoid to the starter motor and the return path from the starter motor to the - terminal of the battery via the engine block and the heavy wire that connects the block to the - terminal of the battery. If any of the wires is broken or disconnected or the starter motor or solenoid is defective the bike won't start.

The solenoid circuit consists of the low current terminals of the solenoid, the neutral switch & the clutch lever switch (between the solenoid and ground), the start button (between the solenoid and battery +) and the wires that connect them. Some circuits also include diodes to prevent the neutral light from coming on when the clutch lever is pulled in.

To troubleshoot the starter system you will need to connect the negative lead of a voltmeter or test light to a known good ground point (motor mount bolts are usually good) and check for voltage by touching the positive lead to the points mentioned below.

- The first thing to do is to determine if there is voltage between the starter motor and ground when the START button is pressed.
If there is voltage and the starter motor does not turn the starter motor itself is probably at fault.
- If there is no voltage at the starter motor, check the voltage at the high current terminals of the solenoid (your shop manual should tell you where it is, or you can follow the heavy wire from the battery +).
There should be voltage at the terminal that is connected to the battery all the time and voltage at the terminal that is connected to the starter motor only while the START button is pressed.
If there is no voltage at the solenoid terminal connected to the battery + either the battery is dead or the heavy wire that connects them is faulty.
If there is voltage at the solenoid terminal connected to the starter motor but not at the starter motor, the heavy wire that connects them is at fault.
If there is no voltage at the solenoid terminal connected to the starter motor the fault is in either the solenoid or the solenoid circuit.

A word about the solenoid: The solenoid is really just a relay,. If the solenoid circuit delivers voltage to the solenoid a coil inside it becomes magnetic and pulls a steel part into position so that the contacting piece attached to it connects the high current terminals. This allows the circuit that controls the solenoid to carry much less current than the starter motor requires so thinner wires can be used and the START button will last much longer.

- From the wiring diagram, figure out which low current wire is + (connected through the START button)and which is - (connected through the clutch switch and teh neutral switch), then check for voltage at that wire when the START button is pressed.
If there is voltage at the low current + wire and not at the high current terminal that is connected to the starter motor, the solenoid is probably at fault.
If there is no voltage at the low current + wire the problem is in the solenoid circuit.
- By following the solenoid circuit in your wiring drawing you should be able to determine when there should be voltage at the appropriate points. If you have come this far, the likely suspects are the clutch switch, the neutral switch and the START button.

BTW: Welcome to the forum and welcome to the world of antique vehicle ownership. Your bike has had 38 years of Previous Owners who may or may not have done the maintenance necessary to keep it safe & reliable. It is highly recommended to go to the CX Wiki (link in my signature) and download the Factory Shop Manual for you specific model (it may be a general manual plus a model specific addendum) and the wiring schematic for your model. Once you have the FSM go through it every maintenance procedure in it no matter whether your bike has reached the specified mileage. Look at any rubber parts with suspicion; Look up how to read tire date codes and if yours are over 5 years old replace them (rubber hardens over time and can no longer flow around the irregularities in the road surface to grip them, especially if it is cool or wet). If it has rubber brake line(s) they should be replaced every 2-3 fluid changed (5-6 years) and yours are probably over 6 times that old; Modern stainless braided lines work better and last practically forever.
Also, please add your bike's model and model year to your signature (see Forum Settings link in my signature) so that you don't have to remember to tell us every time and we don't have to keep asking when you forget.
 

·
Registered
Joined
·
655 Posts
Its old? Joking.
Hope you get it sorted! Bloody CX’s!
 

·
Registered
Joined
·
2,657 Posts
I missed the part where you said starter did nothing, listen to Bob!
 

·
Registered
Joined
·
1,600 Posts
did you check the fuses - the ones in the top handlebar centre cover and the main fuse by the battery? They can look ok but actually have failed
 

·
Registered
Joined
·
37 Posts
Discussion Starter #8
Silly question: Was the transmission in neutral and/or the clutch lever pulled (disengaged) when you were trying to start it? The circuit that triggers the solenoid has protections against starting the engine when in gear unless the clutch is disengaged because that would make the bike begin to move instantly. (We've all done stuff like that when flustered.)
Also, do you hear a click from the solenoid (mounted near the battery on most bikes) when you press the Start button?
Thanks so much for your in-depth response!

The transmission was in neutral with clutch pulled. I tried it in first too, no dice.

No clicking from the solenoid when I hit the start button.

Checked the starter motor. When I connect it's terminal to the battery, it reacts to the juice.

I'm going to get the tank off and check the rest of the points you mentioned.
 

·
Registered
Joined
·
3,804 Posts
Just a side note, did you also make sure that the kill switch is in the run position?
I have on occasion accidentally hit this with gloved hands and not noticed it right away and wondered why it was not starting.
 

·
Registered
Joined
·
409 Posts
A COLOUR WIRING DIAGRAMME FOR MY '81 DELUXE!? I was colourising one from scratch in MS Paint--and I was almost done!

Third vote for "Hey, who moved my kill switch?"
 

·
Super Moderator
Joined
·
11,455 Posts
1 - 13 of 13 Posts
Top