Coil About To Fail?

[Guest]

My 83 550L has stalling issues so I tested the secondary ignitor coils and got readings of 14.5 Kohms on one and 14.8 on the other. Does this mean the coils are about to fail or could they heat up enough while running to cause too much resistance for the ignition to fire properly?

[tom203]

It's more likely your ignitor might have hot issues..... Ignition coil with plug caps removed should measure in 12 kohm range plug wire to plug wire - over caps might add 10 to 20 kohm to that reading. Ignition coils are very durable- sadly 550 ignitors aren't.
When/ how often does this stalling issue occur?

[ColinClayton]

It stalls when coasting to a stop, pulling in the clutch. If I blip the throttle while moving, it will idle alright once I'm stopped. Otherwise I have to set the idle so high the RPMs hang while shifting. The readings I gave were with the caps removed. The caps themselves read about 18 Kohm. Should I test them again while warm?

[tkent02]

It stalls when coasting to a stop, pulling in the clutch. If I blip the throttle while moving, it will idle alright once I'm stopped.

Probably a carburetor thing, doing this wouldn't effect the ignition at all. What have you done with the carburetors?

[ColinClayton]

They've been taken apart completely and dipped in acetone for two days, then boiled in distilled water. They have new gaskets, diaphragms, fuel floats, inlet needles, and needle seats. I tried syncing them, adjusting the float levels, setting the mixture screws, and different jet sizes. The intake and air box boots are in good condition, and I've replaced the intake O rings.

[Who Dat?]

They've been taken apart completely and dipped in acetone for two days, then boiled in distilled water.

Everything you mentioned after this is OK, but maybe you should try using the proper stuff? Acetone is great for many things, but might not be so good a eliminating the gunk that is left from dissolved fuel. Berryman's (or GUNK brand) carb cleaner dip rank up there among the best, Yamaha's concentrate does a pretty decent job, but does not seem to store for very long.

However, let's assume for a moment that the carbs are, in fact, clean. What jets are you using? Are they the stock Mikuni jets or aftermarket jets that came in rebuild kits? What are the settings on your floats? What are the settings on your mixture screws? You "tried" a carb sync, did you get it right?

Just for the record, when a coil (or ignitor) fails, it will take down two cylinders. It will not hang the RPM so you have to blip the throttle to get them down, it will simply run slower and rougher because only two cylinders are firing. If you happen to lose BOTH coils or both sides of the ignitor, the bike simply won't run. Your stated symptoms do not sound anything like that.

[tom203]

Sure sounds like a carb air leak- and since it's noticeable when hot.......... When you replaced intake o-rings at head interface, did you get the suzuki ones (or the cycleoring) ?

[ColinClayton]

UPDATE
I replaced the springs and resistors in the spark plug caps with solid copper wire and after some puffs of smoke from the tailpipe, the problem vanished.

[tom203]

UPDATE
I replaced the springs and resistors in the spark plug caps with solid copper wire and after some puffs of smoke from the tailpipe, the problem vanished.

Thanks for update- bound to remind someone else to check the simple stuff! Might encourage me to change my caps as preventive maintenance....

[londonboards]

If you are still not sure if the coil is working - try this:

Coil Testing Trick