Tricky Yamaha C85 Electrical Problem - 1 cyl OOS - Problem Rolls with Stator wires but new stator - Same issue

[Havana]

Hello,

I have a tricky problem
1992 Yaaha C85 model c85tlrq
Issue : no fire top cylinder

troubleshooting

replace trigger coil - same problem

replace stator - same problem

This is one of the 3 cyl C85s where there are only two trigger coils. Per the manual two cylinders #1 and 3 are on the same trigger coil and the CDI recognizes the North South direction of the flywheel magnets to determine whether #1 or #3 should fire.

Inter sting observation. When I roll the trigger inputs #1 to #3 on the CDI. No change

When I roll the stator inputs to the CDI from Brown(#1) Red (#2) Blue (#3) to Blue Red Brown the problem moves to the # 3 cylinder. This is why I replaced the stator. Magnets on the flywheel are in the correct orientation, I verified with a magnet that they alternate around the flywheel and are in the correct orientationl.

I would appreciate any direction.
-Havana

 

[99yam40]

are you saying there in no spark on #1 cylinder?
how did you test the spark?

did you check the peak voltages into and out of the CDI with the proper test equipment, and compare those reading to the specs in the service manual for your motor?

it was my understanding that #1 and #3 get the signal to fire spark from the 2 pulser coils one for each, not both from one of those pulser coils

 

[Havana]

are you saying there in no spark on #1 cylinder?
how did you test the spark?

did you check the peak voltages into and out of the CDI with the proper test equipment, and compare those reading to the specs in the service manual for your motor?

it was my understanding that #1 and #3 get the signal to fire spark from the 2 pulser coils one for each, not both from one of those pulser coils

are you saying there in no spark on #1 cylinder?
how did you test the spark?

did you check the peak voltages into and out of the CDI with the proper test equipment, and compare those reading to the specs in the service manual for your motor?

it was my understanding that #1 and #3 get the signal to fire spark from the 2 pulser coils one for each, not both from one of those pulser coils

99Yam40 thank you for your quick reply, and your insight.

I tested the spark in using a timing light. When I roll the phases (3 phase) on the stator the problem follows. To me this indicates the signal is properly delivered across the CDI.
I performed static measurements across the stator and CDI and pulser coil and all are in spec. Active tests indicate AC voltage from the stator downward to the engine and all are all within spec.
The new stator and pulser does the exact same thing . This points me to magnets on the flywheel assemble which check out with a polarity test.

The service manual states
of the 3 cylinders , with this motor " #1 pulser actually controls two cylinders . These 2 cylinders are not firing at the same time. In orde to allow 2 cylinders to fire from 1 pulser at different times, the pulser must tell the CDI box when o ignite the appropriate cylinder. This is accomplished by taking advantage of the characteristic of the induction process. As a magnet goes by the pulser electricity is generated. This current flows to the igniter (CDI) box . The direction of the current flows is determined by which end ( north or south) of the magnet travels past the coil first. When the south end of the magnet goes by, the current flows in the opposite direction. The CDI box can differentiate the direction of the current flow and direct the signal to the appropriate capacitor.

Long story short, 2 of the 3 cylinders fire off one pulser seperated by the CDI units capability to distinguish between N/S on the same magnet head. C85 Yamaha.
-Havana

 

[99yam40]

all I can say is good luck.
I have never read anything like that before in a Yamaha Service manual.
the 90 should be the same as the 85 in my thoughts.
and it fires plug #1 off of one pulser and #3 off of the other pulser coil
#2 is made up by the CDI .
peak voltage readings need to be taken with a special voltmeter or a DVA adapter and regular meter set to DCV.
Specs are given as minimum ,so above is good ,but under is bad
what are the readings you get from the pulser coils to the CDI
what are the charge coil to CDI readings
what are the output readings from CDI to the ignition coils
are you taking the reading open or loaded( hooked up using a special harness)
I have no idea what you mean by "When I roll the phases (3 phase) on the stator the problem follows."
follows what to where?

 

[boscoe99]

When I roll the phases (3 phase) on the stator the problem follows. To me this indicates the signal is properly delivered across the CDI.

-Havana

Can you expand upon what this means?

Yamaha uses the terms charge coil and pulser coil.

 

[99yam40]

Boscoe, you know anything about a C85 ingition system?
should it be the same as a 90 about that year?

 

[Havana]

Can you expand upon what this means?

Yamaha uses the terms charge coil and pulser coil.

Yes, stator has 5 wires total .Two wires that run to the rectifier for the charge coil. The lighting coil on the stator has three wires(Brown,Red,Blue)that run down to the CDI and feed through to each each cylinders coil pack. When I roll the phases going into the CDI and move it to Blue,Red,Brown, the problem follows the Brown wire.

So no spark on top cyl ( brown wire in #1 CDI position) roll brown#1 and blue #3 and the problem moves the the bottom cylinder.

This is what made me buy a new stator to begin with.
Is this make it a little more clear ?
Havana

Thanks

 

[99yam40]

just for your information, the lighting coil feeds the rectifier/regulator to charge the battery.
charge coil feeds into the CDI to charge up the capacitor for ignition system and so does the 2 pulser coils

 

[boscoe99]

It's the "roll" part that I don't understand.

The "stator" has several functions.

The wires to the rectifier/regulator are from the lighting coil. Think of electricity for lights.

The wires from the charge coils feed electricity to the CDI box. To charge capacitors. In preparation for feeding that electricity to the ignition coils.

The wires from the pulser coils tell the CDI box when to release the electricity from the capacitors to the ignition coils.

 

[boscoe99]

Yes, stator has 5 wires total .Two wires that run to the rectifier for the charge coil. The lighting coil on the stator has three wires(Brown,Red,Blue)that run down to the CDI and feed through to each each cylinders coil pack. When I roll the phases going into the CDI and move it to Blue,Red,Brown, the problem follows the Brown wire.

So no spark on top cyl ( brown wire in #1 CDI position) roll brown#1 and blue #3 and the problem moves the the bottom cylinder.

This is what made me buy a new stator to begin with.
Is this make it a little more clear ?
Havana

Thanks

This is what I am not understanding. Is English your native tongue?

 

[boscoe99]

Boscoe, you know anything about a C85 ingition system?
should it be the same as a 90 about that year?

The 1992 90 two stroke uses a crank position sender. The 1992 C85 does not.

 

[boscoe99]

This is one of the 3 cyl C85s where there are only two trigger coils. Per the manual two cylinders #1 and 3 are on the same trigger coil and the CDI recognizes the North South direction of the flywheel magnets to determine whether #1 or #3 should fire.

This is one of the 3 cyl C85s where there are only two trigger coils. Per the manual two cylinders #1 and 3 are on the same trigger coil and the CDI recognizes the North South direction of the flywheel magnets to determine whether #1 or #3 should fire.

In what manual are you seeing this information?

This is one of the 3 cyl C85s where there are only two trigger coils. Per the manual two cylinders #1 and 3 are on the same trigger coil and the CDI recognizes the North South direction of the flywheel magnets to determine whether #1 or #3 should fire.

In what manual are you seeing this information?

 

[99yam40]

I missed it earlier, seems he just swapped the brown and blue wires from stater to CDI. red stayed the same
I have no idea what those 3 wires are from.
charge coils or maybe charge and pulser coils

looking at a parts drawing/pic the stator seems to have 2 charge coils and 8 lighting coils
pulser coils are separate and there are 2 of them mounted on the assembly

I have heard of high and low speed charge coils before, but I am wondering if the stater has one charge coil and a built in crank position sensor maybe

 

[boscoe99]

Those appear to be low speed and high speed charge coils.

 

[boscoe99]

I missed it earlier, seems he just swapped the brown and blue wires from stater to CDI. red stayed the same
I have no idea what those 3 wires are from.
charge coils or maybe charge and pulser coils

looking at a parts drawing/pic the stator seems to have 2 charge coils and 8 lighting coils
pulser coils are separate and there are 2 of them mounted on the assembly

I have heard of high and low speed charge coils before, but I am wondering if the stater has one charge coil and a built in crank position sensor maybe

99yam I found some data where Yamaha addresses the use of one pulser coil being used to fire two cylinders but at different times. The info I have applies to the V4 two stroke Yamaha models but perhaps it also applies to the OP's model. Whatever manual the OP is using seems to address this methodology. It is not in the service manual that I have for a C85 model motor.

 

[boscoe99]

 

[99yam40]

It would be nice to know what those coils are (3,4, 5 , & 16

 

[boscoe99]

It would. lol

 

[boscoe99]

99yam did you ever use the Excel program by Microsoft?

 

[99yam40]

99yam did you ever use the Excel program by Microsoft?

probably at work back before 2006,
but I did not create much with it


I am surprised to see just one pulser coil on that 90