Power loss

[motoman]

Just changed that before the trip to Michigan when my charging system cooked.

Charging system is working better now than it ever has. 13.75v at
about 3500.

Double check voltage input at coils.............better be the same as batt, with keyon.

[BA80]

Double check voltage input at coils.............better be the same as batt, with keyon.

Checked it in San Antonio. As I said before, with all other fuses pulled but the main and ignition it was only 2/10 difference. About the same as from one side of the fuse to the other.

[motoman]

Checked it in San Antonio. As I said before, with all other fuses pulled but the main and ignition it was only 2/10 difference. About the same as from one side of the fuse to the other.

Still haven't said you had checked the coil input voltage. Pull the dern tank off, and unplug coils, meter probes into feed wires for the voltage check TO the coils. Also with those wires of, check across coil post in ohms position on meter, More than .2 drop or rise, kiss those coils goodbye. Sounds like yo said you still have stock coils..........file 13 them anyways.

[BA80]

Yes Brant, that's exactly what I'm saying. I pulled the tank and seat and disconnected each connector and checked voltage at each one.

I am, however, going to run a wire straight from the battery to the ballast resistor just to be sure. As soon as I get a chance.

I just want to be sure I'm not the idiot you think I am.

[CaptonZap]

Another test for coil output is to take two old plugs and break the ground wires off. Plug the plugs into the two ignition wires, lay the plugs on the head, and crank the starter. The distance from the center electrode to the shell should need a minimum of 6 to 8 Kilo Volts to spark across the gap, (in ambient air, and yes, a difference in altitude will affect the break down voltage, but work with me here.) The spark should be a blue color, and have a sharp snap. If it is yellow or orange, the spark is weak. Try new coils.
The breakdown field for air is 30kV/cm. Plus or minus.

CZ

[BA80]

Yup. I took an old plug and hooked a plug wire first from #4 cylinder then from #2 cylinder. Orange spark even when I revved it. That was with the ground still on there.

I'm gonna flat wire the resistor straight from the battery just as a test. If Brant is right I may never tell him.

[motoman]

Yes Brant, that's exactly what I'm saying. I pulled the tank and seat and disconnected each connector and checked voltage at each one.

I am, however, going to run a wire straight from the battery to the ballast resistor just to be sure. As soon as I get a chance.

I just want to be sure I'm not the idiot you think I am.

Nope!...............your fortunate enough that I have squaters rights on that last remark.

[BA80]

Alright, I ran a wire directly from the battery to the ballast resistor and bypassed all the original wiring and switches where magic smoke can get lost. The spark was a little better but still an orangish blue. No change

Beating my head against the wall now.

All I can think to do at this point is try another set of coils. Trying to get my hands on a set of 3ohm Honda VFR coils like motoman suggests.

[dbeardslee]

You might try grafting some new high tension wires in the earlier model coils. 35 year old high tension wires are not a good thing. It's easier to do on the pre-81 coils and I've done it on several sets of coils. It makes a difference. Here's the thread that shows how - New wires in old coils

If you want to check your high tension wires for voltage leakage get it in a dark place, get it running, and spritz some water on the high tension wires. If you see blue sparks jumping around you definitely want to change the wires or the coils.

Resistor caps can also be an issue. They do wear out, but that should show up in the resistance measurement across the high tension wires. Non resistor caps might get you a little better spark, and you can get 'em at O'Reilly auto parts for $1.39 ea. Clip a little off the end of the high tension wires if you change the caps to get a good connection.

[BA80]

These caps are only about a year old and I tested them when I changed coils and they all measure 4.5 - 5 ohms. As for the wires, I changed coils twice and I've ridden in rain, sometime pretty heavy, with no change in how it acts.

It's not misfiring per say, it's bogging but popping at the same time. It feels like it's either drowning in fuel or starving for fuel. That's why I've tried 3 different sets of carbs with different jet combinations.

I did a compression check a little bit ago and it's 115/105/105/115. No issue there.

[dbeardslee]

These caps are only about a year old and I tested them when I changed coils and they all measure 4.5 - 5 ohms. As for the wires, I changed coils twice and I've ridden in rain, sometime pretty heavy, with no change in how it acts.

It's not misfiring per say, it's bogging but popping at the same time. It feels like it's either drowning in fuel or starving for fuel. That's why I've tried 3 different sets of carbs with different jet combinations.

I did a compression check a little bit ago and it's 115/105/105/115. No issue there.

What's the resistance measurement across the high tension wires?

[BA80]

With the caps on both measure right at 25ohms

[dbeardslee]

With the caps on both measure right at 25ohms

I hope you mean 25k ohms. Just out of curiosity, what kind of plugs are you running?

[dbeardslee]

Also, you might check the resistance readings again with the engine fully warmed up. I was reading through The when why and how on replacing your coils and it mentioned problems that can occur when the coils are warmed up that might not show up when they're cold.

[BA80]

i hope you mean 25k ohms. :d just out of curiosity, what kind of plugs are you running?

ngk bp6es..............