Ignition coil/signal generator

[Guest]

OK, so Ive been having trouble starting the bike. My previous threads have described my issues. Besides those issues I have a question about some electrical stuff. I tested the ignition coils the way the service manual stated (use an ohm meter and stick the leads inside the leads that go over the spark plugs) The left ignition coil read 24.48K and the right coil read 32.81K. Seems like the left side is weak. Also, I tested the signal generator the way the manual states (use ohm meter and stick leads on Bl(black?) and G(green)) I got 62.4. This also seems low according to the manual. Could these be reasons my bike is not starting right away, but eventually does start(by that i mean, about 5-10 min of trying to get her started).
My previous threads include me redoing the carbs, which is how i came across this. Trying to start the bike to get the carbs tuned in, and its being very difficult. Any thoughts?
Cheers

[Nessism]

Have you properly rebuilt the carbs including soaking them in carb dip and replacing all the O-rings? Is the airbox and stock mufflers in place, or has the bike been rejetted to account for modifications? Have the valves been adjusted? Please describe all the maintenance you have performed so we can understand what the problem is not.

[Chris P]

Thats fair.
1-Cleaned and rebuilt carbs by dipping each for 24hrs.(cleaned and reused stock brass) Replaced all o-rings within carbs. Bench synched carbs before install, Mixture screws are out 3 turns
2-Replaced o-rings for boots (the ones attached to engine side)
3-Did the valve clearances, replaced gasket as well as breather gasket
4-New starter(bc that broke when trying to do this the first time)
5-Air box is attached and sealed with filter inside(filter could use a cleaning probably)
6-New Battery
7-New spark plugs
8-Poured blood, sweat, and tears into her as well(despite the rumors, this hasnt helped)

When the bike has started, it will idle. I had to adjust the throttle screw while I opened the choke bc as i opened the choke she started to sputter and die out. I went to start adjusting the mixture screws and she stalled out. Tried to get her started again, and it was taking a bit for her to get started. I was under the assumption she should just fire up. Decided to check some electrical stuff, and this is where im at.

[Nessism]

Okay, good work on the maintenance. I stay out of threads where guys are struggling but haven't performed any maintenance up front.

So you verified the choke passages are open, both in the carb body and in the float bowl, per the tutorial linked in my signature? Assuming yes, you might want to measure fuel level in the carbs to assure they are filling properly. You could have a petcock issue.

Sometimes the plug caps go bad, or the screw on attachment to the coil wire corrodes. You might want to unscrew the caps, check each individually for 5k ohms resistance, snip off 1/2" of wire, then screw them back on to assure you have good continuity there. Also check for voltage at the coils, and take mitigation action if there is less than 11 volts or so.

Good luck

[Chris P]

Sometimes the plug caps go bad, or the screw on attachment to the coil wire corrodes. You might want to unscrew the caps, check each individually for 5k ohms resistance, snip off 1/2" of wire, then screw them back on to assure you have good continuity there. Also check for voltage at the coils, and take mitigation action if there is less than 11 volts or so.

Good luck

Could you be more descriptive about the plug caps and coil wire? When you say unscrew the caps, do you mean where the lead wire meats the coil or where the lead wire meets the spark plug. Also, how would I check voltage at the coils? Im sorry, electrical is not one of my strengths. Do i just go from one of the coil leads to the other? do i need to turn the bike on? or is just being hooked up the battery good enough?

[tom203]

The signal generator test for 650E (not shafties) says between each wire and ground should be 60 to 80 ohms. you said 62, so, if this is your measurement, the signal coils are good.

Unscrew plug caps from spark plug leads- stick meter probes into the leads from the ignition coil. You'll probably find it about 12kohms on each coil. Plug caps are harder to get resistance reading on. They might be 5kohm to 10kohm each depending on maker.
The ignition coils are marked + and - on spade connections (if you still have stock coils). disconnected from harness, measuring across these spades should give you about 4 ohms.

[jbthomp]

Mine was hard starting like that too and I found out i only had 10v at the coils and would get less and less the longer the bike ran. I did the coil relay mod and it starts fine now. Might check your battery first and make sure it is good.

http://members.dslextreme.com/users/bikecliff/images/coil_relay_mod.html

[Chris P]

Ok so, I ran a few electrical tests, maybe this will help diagnose the problem. Keep in mind I have not noted (K)ohms or other measurements. I just looked at the meter and wrote down the numbers, I think you guys will get the jist though.

I tested the resistance of the signal generator, the BL/W wires were jumped together at the generator and was represented by a single BL/W wire in the connector. So the from the BR-BL/W was 62.3ohms and G/W-BL/W was 61.9ohms. According to book this is within specs, on the low end but good.

I then tested the left ignition coil(bad one?) and right ignition coils primary coil. According to book, check where the connections are and registered ohms. Right side 4ohm, left side .9ohm(seems like the problem is here??!)

The secondary coil test(this was done by placing meter leads into the plug wires, where normally they would fit over the spark plug) gave me: right side 32.8ohm, left side 24.4ohm.

Voltage level on Battery was 12.34(not fully charged) Right coil was 9.96, left coil was 9.16

Conclusion: It seems to me that although the voltage drop is significant from battery to coils, the more important number is the .9ohms across the left coil. Does this mean the primary coil inside is fried? Would this be the cause as to why the bike is having trouble starting? but, shouldnt the bike be able to use the other coil to start? Or does the engine use cylinder 1 to begin the process?

[Recoush]

Hello,
noticed your coil voltage was below the 12v not at 9V and some said min was 10V? you may have corroded or bad wires to the coils

their is a recommendation to Install a relay and run hot from the battery to the
ignition coil wires abandoning the old power wires to the ignition

all i can say is this works great for me and the forum and Bassciff has a wonderful site recommend checking out the suggested link by Jbthomp

[tom203]

That left side coil reading of .9 ohms on primary means it's no good- this would also draw more current from battery causing more voltage drop like you reported. Get a a new-to-you coil. These things rarely go bad, so used ones are fairly safe bets.

Edit; do your coils have spade connectors on them, or are wires coming out?

[Chris P]

Does anyone know where i can find the specs for the coil? Or maybe just what it is that I need?

[tom203]

recall this ?

"Unscrew plug caps from spark plug leads- stick meter probes into the leads from the ignition coil. You'll probably find it about 12kohms on each coil. Plug caps are harder to get resistance reading on. They might be 5kohm to 10kohm each depending on maker.
The ignition coils are marked + and - on spade connections (if you still have stock coils). disconnected from harness, measuring across these spades should give you about 4 ohms"

Mine coils have mounting bolts on about 3.5 inch centers- what are yours?

[Chris P]

"Unscrew plug caps from spark plug leads- stick meter probes into the leads from the ignition coil."

Sorry I may be misunderstanding the terms your using, I think I did this test. I took off the wires that fit over the spark plug and put the red meter lead in one and the black meter lead in the other, i tested for resistance(ohms) and got 32.8ohm for the right coil, and 24.4ohm for the left coil. Is this what you mean??? Or do you want me to pull the cables out of the ignition coil completely and test the inside of the coil??

"The ignition coils are marked + and - on spade connections (if you still have stock coils). disconnected from harness, measuring across these spades should give you about 4 ohms"

Im assuming I have one stock coil and one aftermarket. The stock coil(with the spade connections) reads 4ohms, the aftermarket(which has soldered connections) reads .9ohms.

Im not in front of the bike right now, but 3.5 inches sounds about right

[tom203]

Unscrew spark plug caps from plug wires, stick meter probes in these wires that go to coil and you should find about 12kohm for resistance

Edit; some suzuki coils have mounting bolts with about 4 inch centerline spacing

[Chris P]

Ok so I did this and I got approx. 14.59kohm.
Does this mean my coil is fine and I need to cut off some of the plug wire and reattach?
If that is the case what was the .9ohm across the coil all about?