Topic: Checked Timing and Ignition: 400Four: "Interesting" results inside.

[brandon]

Long read but lots of data:

Last Saturday, I thought I'd pull the timing cover off the 400 Four and see how the timing was. Since I've owned the bike, I really haven't done anything to the ignition system or carbs. Well, I pulled the carbs off twice. Once to check the condition of the internals, give them a cleaning and the second time to bench sync the carbs using Too Tired's light method, which works quite well BTW.

Last Saturday, I didn't have my own timing light so I borrowed a neighbors which had an advanced ignition knob on it that was broken and spun freely. Unable to get a reading that I was comfortable with because of the spinning knob, I really didn't know what my ignition was doing. However, I did notice that when I had the timing light on spark plug wires 1 or 4, I would get an uneven flash. As in the light would have even flashes then a random subtle pause. This pause would coenside with a slight hestiation that I could hear as the bike would idle. Interesting.

Today, I rode the bike to Sears (about 40 miles round trip) to pick up a new timing light so I could get a better idea of what was going on. Sitting next to the timing lights were Dwell meters, so I purchased both and rode home.

Upon getting home, I pulled the timing cover and started logging data. Using a Craftsman Professional Advanced Inductive Timing Light #21023 I checked the timing marks 1.4 and 2.3. Points are eight months old. Plate is #333 and eight months old.



Idle: 1,100-1,200RPM
Battery: Water to full marks 12.2V
Carb A/F: 1.75 turns out
Carb Filters: Individual pods
Carbs synced: Light Method - benched
Exhaust: OEM 4-1
Vacuum Leak: Negative
Spark Plugs: D8EA gapped too 0.8mm - Four days old
Tappet Clearance: I have not checked it since my ownership = eight months

With the timing light on:
#1 = 16.5 degrees - fluctuating 2-3 degrees
#4 = 11.5 degrees - fluctuating 2-3 degrees

#2 = 25 degrees - stable
#3 = 25 degrees - stable

How did I come to these numbers? I used the advance dial on the back of the timing light and slowly adjusted the light pulse until the F marks lined up with the static line on the 333 plate. I was still getting spuratic light pulses with the new timing light with it hooked up to both #1 and #4 spark plug wires.
***

Next I wanted to check the Dwell. I was curious to see how close the last owner got too with using feeler gauges. The dwell meter is an Actron Meter #CD7605 and I took my readings off of the 8cyl scale. Before checking, I researched this site and found that by using the 8cyl scale, the dwell should read between 23 and 24.5.

#1.4 Dwell = 9 @ 8cyl scale
#2.3 Dwell = 14 @ 8cyl scale
***

After checking the dwell, I pulled the tank and checked the spark plug wires and coils looking for continuity and no continuity respectively. I used a Fluke Digital Mulitimeter 189 for these tests. Tests were performed with the power to the bike turned off. I checked these things in this order (please refer to diagram):
1) Continuity between both small wires relative to the center conducter feeding the coils juice.
2) Continuity between both plug wires relative to their coils (with out the spark plug caps).
3) Continuity between any small wire to the spark plug wires relative to their coils.
4) Continuity between both small wires per coil (Should read 5 Ohms +/- 1 Ohm).

Here are my results:
1) 1.4 coil lead A to power source = 5.87 Ohms
----2.3 coil lead A to power source = 0 Ohms

2) 1.4 = 15.956 Ohms
----2.3 = 15.059 Ohms

3) 1.4 A to 2.3 A = 5.77 Ohms
----1.4 B to 2.3 B = 2.7 Ohms
----1.4 A to 2.3 B = 1.34 Ohms
----1.4 B to 2.3 A = 4.73 Ohms

4) 1.4 A to 1.4 B = 1.10 Ohms
----2.3 A to 2.3 B = 4.62 Ohms

Coil Voltage at input was 10.8V with battery reading 12.1V (bike system power turned off).


Upon close inspection of the 1.4 coil it became apearent to me that there was some kind of waxy residue on it, as if someone had melted a candle on it. What I found interesting was that where the soldering points were, the wax was built up and extended about 1/4" off the coil on both ends respectively. With the simple light test with the timing light, I was suspecting that the 1.4 coil was on it's way out. After performing these continuity tests I think this more or less confirmed. Perhaps some of you regs with your infinite wisdom can take a look at my data and tell me just how seriously out of whack my timing and electrical system is. Thanks a bunch and thanks for reading.

If there are more thorough tests I can perform or I did something wrong, please let me know. I will retest and post results.

Aloha Nui Loa,
Brandon

[Bodi]

Using a dial-back timing light you have to line up the T mark, not the F mark. (advance degrees references to TDC, not the already advanced T mark)
I suggest setting the dwell (points gap) and timing before going much further. It won't have to be done again if you need a new coil and if the bike runs great after adjustment you may not need one. This is a thoroughly nasty frustrating banging-your-head-on-the-wall job if there's any slop between the big points plate and the case studs that locate it... I've punched the edge of plates to get a snug fit and TT uses a metal shim at one stud: either way once the plate is snug and won't move radially when you rotate it you're good to go. Set the timing at full advance, about 3000 RPM but you'll see the timing marks move then stop as RPMs rise and the advancer rotates. Full advance is 23.5 to 26.5 degrees. I would set it on the advance line with zero dial-back and then dial back to the T line and see what you read to make sure the numbers are right.
It does look like a bad coil on 1-4 but I am not sure of your measurement technique. The "wax" extruding out suggests overheating, that isn't necessarily fatal but it's a bad sign.
Disconnect all the coil wires before testing and make sure none are touching the frame or each other.
The primary coils - black to (yellow or blue depending on which coil) should be quite close to 5 ohms. With such low resistance measurements, touch the meter leads together and subtract whatever ohms reading you get from the measurement reading.
The secondary coils - plug wire to plug wire - should be around 15000 ohms (15K). Your readings are probably correct and you left out the K.
The primary and secondary leads should have no connection at all, reading "infinity", "error", or "OL" on your meter when testing between a primary and secondary wire.
Low primary resistance and leaking dielectric means the primary windings are shorted inside, new coil time. Any connection between the primary and secondary usually means no spark on one plug so probably not a problem for you. New coil time if you show a connection though.
Measuring from the harness end of the blue and yellow wires to ground you should have very low resistance - close to zero ohms -
when the points are closed (rotate the crankshaft to close if open).
With your Fluke 189 you can measure the capacitors, put the probes across the points with the points open. They should be 0.22 uF each, Honda says replace if below 0.2uF but if above 1.2 or so they aren't your problem (but replace anyway below 0.2).

[brandon]

I tested the coils via the Ignition and Spark FAQ that another member posted. The information you provided looks to be interesting. In my testing of the coils I didn't have the points opened or closed to their respective coils, didn't have the coil wires unplugged from the main, nor did I have the aux. power on.

I'll retest tomorrow with the coil power leads disconnected from the Y connector and see what happens and post my results. I am however, leaning toward the fact that the 1.4 coil may be on it's way out. If this is the case, and the spark is spuratic at times, will it not be difficult to time? As far as the timing plate, it is very snug and spins evenly around it's axis.

Is there anything else that I'm missing? Should I replace the coils with something different, like GL1100 coils or whatver that other Honda bike is? Or replace with the respective coils? I'd like to keep it as simple and effective as possible.

Tomorrow I'll recheck:
The coils using your methods
The points using your methods

Sunday I'll check:
Timing using your methods
Anything else that arises from member responses.