Spark Mystery

[dnsmith]

I have been working on getting my 78 GS550 working. Up to this point I was getting it to run ( barely) but some of the cylinders were not consistent. It would die if I hit the throttle more than halfway sometimes if I touched it at all. Sometimes it would rev high with the throttle and then die after. Anyway I figured the carbs were way out of adjusment. However sometimes one of the pipes would stay cold indicating it was not firing. ( not always the same one of different occasions). IE number 4 one time. and number 2 another time. Sometimes they will fire up after a while and then stop again. I checked it out and I had weak spark. Previous to this I cleaned and rebuilt the carbs replaced the boots and rings and adjusted all the valves into spec.
I got a set of coils from another running 550 of the same year and tried that with a marginal improvement. I then decided to go with the dyna s system because I hate messing with points. I checked the spark and it was good. I tried to fire it up and it sputtered and coughed as usual ( starts hard) and then after about 2 min of trying different choke settings throttle combinations (ie adjust crank for 3-4 secs, try a different way crank for 3-4 sec) a little bit of starter fluid, it quit catching at all. I check for spark and all 4 have nothing.
Things I have checked. 12.5 V on the battery. The plugs have less than 30 min actual engine run time but are just over a year old. 12V at the orange/white on the coil. primary resistance on the coil 3.5 ohms on both coils, and secondary on both is 35K ohms. The dyna S red lead has 12V. (Produced a great spark at first) The 12V on the orange/white cuts on and off with the ignition and run switch. It cranks but 0 spark on any plugs or combinations of wires or plugs. I am at a complete loss! Where do I go fro here?

 

[Guest]

Are the carbs clean?

 

[dnsmith]

Yes they are I just went through them the day before. I can't get back to that problem until I figure out why my spark has completely disappeared. I need to see what other problem areas might be the cause of my spark mystery.

 

[Go Mifune]

How is the timing? Does the Dyna have black and white wires that go to the orange ones? If so make sure those have power at the right time.

 

[Steve]

With that much cranking, how is the battery? Check voltage before you turn on the key and while cranking.

You can't go through the carbs in a day, if they are plugged up.

Hard starting is also indicitave of tight valves. When is the last time they were checked?

.

 

[dnsmith]

I have been working on this for 2 years on and off as I get the time. The carbs were pulled apart individually cleaned (dipped) and the replaceable parts replaced with a parts from a carb kit put back together and bench set. So far I can't focus on tuning them in since my spark is now absent completely. There was spark right after the dyna kit was put on and then it was gone. The battery was on a charger while I was cranking it and now overnight. I checked it again this morning and there still is no spark. The black and white wires from the dyna are hooked up to the proper black and white coil wires. The timing was statically set as close as possible with the timing light and instructions provided. 12 volts at the orange/white wires and 12 V on the red dyna s lead wires. I am baffled?

I adjusted the valves when I was working on it last year with no actual engine run time since. Maybe a few minutes of idle as I have tried working on various systems.

 

[gorrbert]

Charging While Starting

Charging While Starting

I would be careful doing this. I burned out my stator with a charger. I feel it may be better to charge the battery off the bike to avoid harming your ignition system. It's cheaper. Gord.

 

[dnsmith]

good advice I will do that from now on. Anyone have any thoughts as to why my spark suddenly disappeared besides what I have already checked?

 

[Guest]

Did you ever leave the ignition on for a long period of time without starting it? This can burn the Dyna.

 

[dnsmith]

No I have been carefull to not try and crank it for too long and always turn the key off when I don't need to test something.
Update I got spark last night after getting new plugs and I ran it and I at least have a baseline to start tuning the carbs. I rode it and it was very sluggish. The plugs afterwards are sooty and black. running very Rich? Then today I went to start it and it wouldn't CHecked for spark and it was gone again. What could be wrong? Spark one day gone the next then back

 

[ryonker]

Did you use the clamp (white) splicer when wiring the dyna? I had issues with mine initially because it has to be clamped super tight to the orange/white coil wire. If the splice is not firmly connected, you might get the dyna working at times and then not working. You can always make a more permanent splice and toss out the one that comes with the Dyna S.

Rick

 

[Guest]

Did you use the clamp (white) splicer when wiring the dyna? I had issues with mine initially because it has to be clamped super tight to the orange/white coil wire. If the splice is not firmly connected, you might get the dyna working at times and then not working. You can always make a more permanent splice and toss out the one that comes with the Dyna S.

Rick

I soldered mine. Thank goodness for Dynatek but those connectors are crap.

 

[Spyderman]

I soldered mine. Thank goodness for Dynatek but those connectors are crap.

so did i i took one look at that connector and pitched it in the bin