Help needed troubleshooting Ignition System

[Guest]

I've got an 82 650 that's only running on cylinder 1 & 4. How do I know this, the plugs for cylinder 2 & 3 look brand new after being in the bike for about a month.

I swapped the coil that runs cylinder 1 & 4 with the coil that runs 2 & 3. Both coils with run 1 & 4. Both coils fail with 2 & 3.

I'm now trying to track this problem down using the clymer manual and it's making me want to track down and torture the writer. I'm not educated with electrical work but I do know how to follow instructions so if any one can give me better instructions on how to track this electrical gremlin down it would be much appreciated.

Just please don't say things like 'use the R1 scale for ohms'. There's no damn R1 scale written anywhere on any multimeter I've ever seen so what the hell do you mean clymer. Or just give really vague instructions like 'disconnect the connector and check the signal generator side' but then fail to identify which side is the signal generator side. It's not that hard to say check the end with the female connection or male. It's cramped in there and the engine is still hot, I can't just shove my hand in there and tracked where the wires are going. Come on Clymer, put a little effort into this. Sorry, I had to vent about that horrible half assed manual.

[Nessism]

http://zeus.mtsac.edu/~cliff/storage/gs/GS650GManual.pdf

[unfocused]

Have you pulled your ignition cover off of (i assume) the right side like mine? Inspected for burnt/broken wires?

You also have a orange/white? for battery positive with key on. make sure both of those have power when the key is turned on.

Looks like you have a white and then a black/yellow wire for your signal wires to your coil. check those with a test light for blinky ( clip to known good ground ) and crank the engine. test light should blink fast as its reading rpms sorta.

P.S. don't ride it like that because un-burnt fuel is a wonderful solvent and it'll wash those cylinders out.

hope this helps. I am going to dinner. Be back on 9:30p.m.ishhhh florida time

this is exactly what i did today to test my new to me 1977 GS 750 with no spark. It has a dyna s ignition system conversion installed. Both coils are dead.

FYI: don't leave your key on for more than a minute or 2 without starting the engine because this can overheat and burn coils if done often. If you have a points ignition system this can weld points shut/burn points or condensers up

[MechMessiah]

Thanks all! I spent more time working on this and swapped the CDI box and signal generator with spares I had. Still can't get cylinder 2 & 3 to spark. Looks like the timing for my ignition advance is off. So I'm boned. Well, I do have a spare lower end so I guess I can put the top end and swap that out. Damn.

So what's the danger with riding on 2 cylinders? I've been doing that for the past month apparently.

[Nessism]

Looks like the timing for my ignition advance is off. So I'm boned. Well, I do have a spare lower end so I guess I can put the top end and swap that out. Damn.

.

This makes no sense.

[fastbysuzuki]

Why would you want to swap the bottom end? I'm not familiar with this bike so do you have a igniter or points and condensers ignition? If points are there two sets of points?
heve you checked you have voltage to the coil for 2 &3? Undo the connector to that coil put your meter on 0-20 volt dc put the negative to earth and positive to what should be the live side/feed and see if your getting 12v
yes do not ride it until the problem is resolved.

[tom203]

This is unlikely a signal generator, ignitor,or timing issue..but to check for the latter, remove the little round cover that conceals the signal generator. Look for obvious loose parts.
I'd suspect the four way connector that connects ignitor plug to mating harness plug- it might not be conducting thru. The harness plug could be corroded and not letting 2and3 carry current, so no fire.
most basic multimeters today have 200 ohm scale for lower range..try to find the instruction manual to familiarize yourself.
Avoid bottom end work on this motor at all costs.

[cowboyup3371]

Why would you want to swap out the engine for what sounds more like an electrical problem? It doesn't make any sense

[MechMessiah]

Why would you want to swap out the engine for what sounds more like an electrical problem? It doesn't make any sense

This makes no sense.

Why would you want to swap the bottom end?

Because this engine has never run right in the 3 years I've had this bike and at this point I'm kinda done with it. Add to that when I read in the manual about ignition advance repair and come across "If the advance mechanism must be removed for repair refer to Engine Removal and External Assembly" coupled with comments on here like

Avoid bottom end work on this motor at all costs.

It makes swapping engines seem like an easier route.

[MechMessiah]

heve you checked you have voltage to the coil for 2 &3? Undo the connector to that coil put your meter on 0-20 volt dc put the negative to earth and positive to what should be the live side/feed and see if your getting 12v

No, I haven't. I've been trying to find someone who can tell me how to check this but had no luck so THANK YOU for this info. I'll go check this now.

[MechMessiah]

YOU SEE THAT?! It's a big old spark for cylinder 3!!! Thanks all! Once I checked the voltage I saw the right coil wasn't getting the same power as the left so I checked and cleaned some connection and voila, Spark! I'm so excited to get her back together and do a test ride. Everyone's been tell me I've had fuel system issues with this bike and I've been trying to solve them for years but I think this has been the problem the whole time. Thanks again!

[LAB3]

Pretty much everyone here has a fuel system story that turned out to be ignition related and vice versa. You often feel like an idiot when you finally figure it out, that's where experience comes from!

[MechMessiah]

You often feel like an idiot when you finally figure it out, that's where experience comes from!

That's good to hear. Misery definitely loves company.