No Spark
So you go out to fire up your trusty old warhorse and nothing happens. You check and there is no spark on the plug. Zero, zilch. Nadda. What do you do?
First thing you check is to see if somehow the kill switch got flipped. Many riders at some time in their motorcycling career have cranked the battery down to near flat before noticing that the kill switch is in the OFF position. Don’t feel embarrassed: it happens to just about all of us at one time or another. I did it early on. I was maybe 18 years old. Probably the worst part of the “flipped kill switch” problem is that after you’ve discovered it, you then have a flooded engine to deal with along with an exhausted battery. Not to mention a really irate operator.
If the problem isn’t a flipped kill switch and you have to discover what the problem is, an easy way to start is to divide the ignition system into two sections: before the ignition coil, and after the ignition coil. You’ll need a digital multi-meter (DMM) for any serious analysis, so you’d better plan on acquiring one at this stage if you don’t already have one. They have gotten quite inexpensive in recent years. Or just borrow one from a friend. Next you’ll want to test for an input voltage signal to the ignition coil. You can perform this test with the gas tank still on the bike, but it is easier to get at the connection if you remove the tank. Removing the tank, of course
requires first removing the side-panels and the saddle. If you have a DMM handy and you’re willing to reach up under the tank to pull the low-voltage input wire off the coil, you can perform this test in ten minutes.
The ignition coil is located on the left side of the bike somewhat tucked up under the gas tank: towards the front. There is a black/yellow wire plugged into the coil. This is the ignition signal feed from the CDI. Pull the wire off the coil and connect one lead of the DMM to it. Next, connect the other lead of the DMM to a frame ground: typically an unpainted bolt extending from the frame is a good source for a ground. Turn the DMM on and select “Volts Alternating Current” (VAC) for the DMM’s operating mode. Hit the starter button and crank the engine over for a couple, maybe three seconds. The DMM should register a voltage signal in the 36V to 42V range. If the DMM doesn’t register this strong signal, then you should suspect that the problem lies “upstream” of the coil.
That is, the CDI is not outputting a signal to fire the coil/spark plug. On the other hand, if the DMM does record a signal, then the CDI is trying to fire the coil/spark plug and the problem lies downstream: the coil/plug wire/spark plug become suspect. If the problem is that the CDI is not outputting a signal to the coil, the first thing to suspect is the little miniconnector that connects the pulse generator wires to the CDI Unit. The pulse generator is a rather low powered device and it doesn’t take too much corrosion in its connections to drop the pulse delivered to the CDI below
what the CDI Unit considers minimum to say “OK, I’ve got a pulse, I need to fire the spark.”
What you are looking for is a small two-wire mini-connector located beneath the saddle. Yes, you need to remove the saddle to access it. The pulse generator is located inside the right engine case and two wires exit from its top. These two wires are Blue/Yellow and Green/White in color. They snake beneath the carburetor and up to the left frame rail before disappearing under the saddle. Typically, all it takes is to disconnect the mini-plug and clean the contacts. The usual method is to use Q-tips and spray electrical contact cleaner. {{In an emergency, you might just try disconnecting the mini-plug and plugging it in a few times. The abrasion alone might be sufficient to get you going again.}} While you’re at it, follow the wires to the CDI Unit and disconnect the two connectors that jack into it and clean their contacts.
If you have your DMM handy, you can connect its two leads to the end of the mini-connector running from the pulse generator and check to see if there is a pulse coming from the pulse generator. Turn the DMM to VAC and crank the engine over a few times. The DMM should register around 0.5 V. If there is no signal, or a very weak signal, then there actually is a problem with the pulse generator and it should be inspected further. Typically, however, it is just a bad connection that is the source of the problem.
So what if it isn’t the pulse generator? Below is a systematic way to look at the problem. This was graciously posted up to the Ascot board by “j_reb_78 ‘Kenny’”. He found it on Thumpertalk: “So I‘m having problems with my ascot engine. I‘m not getting spark. Upon checking the net for help I came across this nice walk through on thumpertalk. All rights go out to “oldbob”
”My son recently rode his pride and joy back home 50mile from work. After a short time, he went out to start it again, the starter turned the engine but it would not start. Investigation revealed no spark at the plug. Neither of us knew anything about FT500 ignition systems. However by surfing the net we eventually found out how it should work. We purchased a multimeter for
£4.99 and set about fault finding
1. Remove the low-tension connector from the coil and check that the low-tension resistance to earth is about 1 Ohm. Check that the high-tension resistance from spark plug connector to earth is between 8-15 kOhm. If resistances are vastly out of spec change the coil. Ours was OK.
2. Remove side panels, tank and seat. Locate CDI unit. This is a small black unit with two plugs one with 3 wires the other with 4. Remove connectors.
3. Check Kill Switch and Ignition Switch. With Ignition Switch on and Kill Switch on Run, check that the Black/White lead on the CDI is not connected to earth. Switch Kill Switch to Off, check Black/White lead connects to earth. Switch Kill Switch to Run, Ignition OFF check that the BLACK/White lead is connected to earth. Ours worked OK.
4. Check that the Green lead on the CDI is connected to earth. Ours was OK
5. Check that the Pulsar Coil resistance from the Blue/Yellow lead to Green/White wire is between 500 to 570 Ohms. Ours was OK
6. Check that the Alternator Ignition coil resistances, from White to Earth 260 to 350 Ohms and from Blue to White 70 to 100 Ohms. Bingo we had found the problem there was an open circuit from White to Earth
7. On removing the crank case cover a coil dropped out. It could be seen that it was from the Alternator Stator. The coil had completely worn away a key-way it was supposed to be located in.
We bonded the coil back onto the stator with an aircraft ‘glue’ Reconnected the coil and encapsulated it to the the adjacent coils with epoxy resin. The bike was put back together again and after 4 turns of the starter burst into life again. Whether this repair will last I don’t know but
it is running OK at the moment.
I hope this will help anyone with a similar problem”
Honda FT500 Ascot No Spark 1 GRN Rev. 1 Oct 2008
Y/R Y/R
Y/R
Y/R
Y/R
Y/R
Y/Bl
Y/Bl
R/W
R/W
R/W
R/W
Lg/R
Lg/R
Lg/R
Lg/R
Lg/R
Lg/R
Lg/R
Lg/R
G/Y
G/Y
G/Y
G/Y
G/Y
G/Y
Brake Lights
G/Y
G/Y
G/Y
G/Y
G/Y
G/W
G/W
G/W
G/W
G/R
G/R
G/R
G/R
G/R
G/R
Br/W
Br/W
Br/W
Br/W
Br/W
Br/W
Br/W
Br/W
Br/R
Br/R
Bu/Y
Bu/Y
Bu/Y
Bu/Y
Bu/W
Bu/W
Bu/W
Bu/W
Bl/Y
Bl/Y
Bl/Y
Bl/Y
Bl/Y
Bl/Y
Bl/Br
Bl/Br
Bl/Br
Bl/W
Bl/W
Bl/W
Bl/W
Bl/W
Bl/W
Bl/W
Gr
Gr Gr
Gr
Lg
Lg Lg
Lg
Y Y Y Y Y Y
O
O
O
O
Bl
O Bl
O
O
O
Lb
Lb
Lb
Lb
Bl
Lb
Lb
Lb
Lb
Br
Br
Br Br
Br
Br
Tail Lights
Br
Br
Br
Bu
Bu
Bu
Bu
Bu
Bu
Bu
R
R
R
R
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
Bl
Bl Bl
G
G
G
G
G
G G
Bl
Bl
Bl
Bl
Bl
Bl
Bl
Bl
Bl
Bl
Bl
Bl
Bl
Bl
Bl
Bl
Bl
Bl
Bl
Bl Bl
Bl
Bl
Bl
Bl
Bl Bl
Bl
Bl
Bl
Bl Bl
W
W
W
W
W
IGNITION SWITCH STARTER SWITCH ENGINE STOP SWITCH DIMMER SWITCH HORN SWITCH TURN SIGNAL SWITCH
BAT1 BAT2 TL1 TL2 IG E
OFF
ON
P
BAT2
FREE
PUSH
MG HL1 IG E
OFF
RUN
OFF
HL2 Lo Hi
Lo
(N)
Hi
FREE
PUSH
HO E W R L
L
N
R
Bl
Y
Bu
G
R
W
BLACK
YELLOW
BLUE
GREEN
RED
WHITE
Br
O
Lb
Lg
P
Gr
BROWN
ORANGE
LIGHT BLUE
LIGHT GREEN
PINK
GRAY
GRN Rev 0 Dec 05
SWITCH CONTINUITY
Note: the original wiring diagram fromHonda
had an apparent error in the green wire
(ground) circuit that has been corrected in
this drawing. In the original drawing, the
green wires connecting to the ignition and
starter switches, and the front turn signals
were not connected to the system ground.
HEADLIGHT 12V60/55W
LEFT FRONT TURN SIGNAL 12V32cp(23W)
LEFT REAR TURN SIGNAL 12V32cp(23W)
RIGHT REAR TURN SIGNAL 12V32cp(23W)
BRAKE AND TAIL LIGHT 12V32/3cp(23/8W) -2
TLI TL2BAT1BAT2IG E
E Lo HiHL2 R L WHO
TURN SIGNAL • DIMMER • HORN SWITCH
CLUTCH SWITCH
IGNITION SWITCH
E IG MG HL1BAT2
STARTER • LIGHTING • ENGINE STOP SWITCH
FRONT BRAKE LIGHT SWITCH
FUSE BOX FUSE 15A (HEADLIGHT)
FUSE 10A (TAILLIGHT)
CDI UNIT STARTER CONTROL UNIT
REAR BRAKE LIGHT SWITCH TURN SIGNAL RELAY
HORN
NEUTRAL SWITCH
PICK - UP
ALTERNATOR
REGULATOR
/ RECTIFIER
M
BATTERY
12V14 AH
STARTERRE LAY
FUSE1 5A
(MAIN)
4P
SPARK PLUG
STARTER
SOLENOID
(MINI)
(MINI)
(MINI)
3P
(MINI)
(MINI)
(MINI)
STARTER G - tube
SOLENOID RELAY
Lb - tube
O - tube
O - tube Lb - tube
G - tube
R - tube
SPEEDOMETER LIGHT (12V3.4W)
TACHOMETER LIGHT (12V3.4W)
TURN SIGNAL INDICATOR 12V 3.4W
NEUTRAL INDICATOR 12V3.4W
HIGH BEAM INDICATOR 12V3.4W
G - tube
RIGHT FRONT TURN SIGNAL 12V32cp(23W)
