Will points ignition work without condensers?

[charbot]

May seem like a dumb question but....

I recently acquired a '77 gs400 - abandoned at my apartment building by a previous tenant. Long story short- I got it legal and am working my way through a thorough tune-up. ive been riding it around the neighborhood a bit and id say its running pretty decently.

the issue is that I cant find condensers anywhere on the bike. Seems the coils are wire directly to the points. Would the bike even run without condensers, or are they on there somewhere, still hidden? the stock location is mounted right off the coils.

Also... when adjusting the points, I noticed that the both of the wires (yellow and black) are always grounded (full beep, no resistance), regardless if the points are open or closed. i had to remove the wires from the terminals to check continuity while setting the points.
Is something shorted? the bikes starts on the first kick (usually) so whatever is up, isnt having that big of an impact...however...

...A problem I am having is that it is overly rich at idle Like so rich, that turning on the choke kills the engine. Plugs are always black/gas covered. With a little throttle, The choke works fine. I had assumed that this was a jetting issue, as the PO put on a 2-1 exhaust and replaced the airbox witha single pod and pvc "t" fitting to the 2 carbs and left the carb jetting stock.

I know that I still need to tackle the jetting cause the exhaust and airbox mods should make it lean( lowering the needle clip really helped with off-idle response) but im thinking that the overly rich idle is from no condensers resulting in weak sparks?
What do you guys think?

[rustybronco]

looking the parts diagram, the condensers are attached to the ignition coils and it would run like crap without condensers.

[hampshirehog]

It won't run without condensors.

[charbot]

Yeah, every image Ive seem has them mounted directly on the coils, and they are attached from a terminal on the coil to ground. Im pretty sure that mine are wired directly together- to ground. Like I said, the bike runs decent.

Anyone know approx. what capacitance value is used for these bikes?
i probably have enough component caps to experiment with, before ordering "suzuki" condensers.

[rustybronco]

Anyone know approx. what capacitance value is used for these bikes?
i probably have enough component caps to experiment with, before ordering "suzuki" condensers.

A quick 'search' resulted in this...

http://www.smokstak.com/articles/capacitors.html

My experience is that that capacity of both magneto and spark coil capacitors range from 0.2 microfarad to 0.33 microfarads. Almost all automotive distributor coils use a 0.25-0.29 microfarad capacitor.

[charbot]

Thanks, Im sure I got some .22 ish 24v caps i can try... now where do I connect them?

Here some pics of what Im dealin' with:




image(6) by charleswesleyhobbs, on Flickr



pretty huh? Looks like the ground mounting tab from the condenser is still there (holding the orange(12v) and yellow or black wire (to points) ) You can see two soldered terminals for the 12V and points wire and the heavy wire to the spark plug, no other spot to connect a wire , except the iron laminate core/ mounting posts( which I assume are grounded cuz they are bolted to the frame.) i was wrong in my prev post -There are no wires for the caps wired together to ground- no wires at all and no obvious place to connect. What does the condenser attach to? in the wiring diagram it appears to have its own terminal on the opposite side from the other wires.

heres a stock one:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?VISuperSize&item=260798082906

[rustybronco]

Between the negative side of the coil and ground; just the same as if the were connected to the terminal on the points.

do you see heavy arcing across the point contacts when your bike is running?

http://s612.photobucket.com/albums/tt209/wallowgreen/Garage/?action=view&current=Cap0002.mp4

[charbot]

do you see heavy arcing across the point contacts when your bike is running?
http://s612.photobucket.com/albums/t...nt=Cap0002.mp4

Ah, yes I do.

[rustybronco]

It won't run without condensors.

It will run without condensers. it'll run like crap- backfire- pop and snort and be hard starting, but it will run. the reason I asked about point arcing was to find out if it had any condensers. I sure can't see them coming up missing if the bike runs reasonably well.

Ah, yes I do.

is one side of the point contacts pitted as if a condenser hadn't been connected?

how many wires are connected to each set of points? one? (trying to determine if it truly does not have any connected)

[charbot]

What does the heavy sparking indicate?

Also is should the wires to the points(negative terminal) have continuity to ground regardless of the breaker position. If I do have caps, are they shorted?

I sure can't see them coming up missing if the bike runs reasonably well.

- Im totally cool with moving on to something else if you guy think that its a non issue

[rustybronco]

heavy arcing is an indication the condensers are bad.

Also is should the wires to the points(negative terminal) have continuity to ground regardless of the breaker position

no they shouldn't, but then it wouldn't run either.

first you need to find out for sure if you do, or do not, have condensers fitted.

[charbot]

Im certain that they are not under the tank or by the coils- ive traced the points wires from the coils, through the started motor cavity and out through to the breaker wires, and they arent stuffed in behind the breaker (nor are they mounted on the plate) so Im pretty sure there are no condensers on the bike.

Also, you can see in the third photo that the white wire (negative to points) has been covered in electric tape right near the coil, same case on the other side- I bet thats where the cap connected and they were removed... right?

i retested continuity at the wire terminals on the points - I get about about 10ohms between the yellow or black wire and ground when the points are open. Should be infinte (no connection) correct? Weird. The bike definitely runs, kinda reliably too.

[charbot]

Ok, just inspected the breaker plate and the wires. Im pretty sure it was sparking heavy last time I set the points, but today not so much. A faint spark here and there. maybe it was dirty last time? i took out the plate and inspeted the wire for shorts (and condensers)- there were none. After resetting the points, I started the bike and I tried adding two .22uF/ 100v polyester film caps- one leg alligator-clipped to the breaker wire terminals the other to ground. made no difference what so ever, at least during idle.

Im stumped.

[rustybronco]

Do you have an old analogue voltmeter or does' your dvom have a bargraph on it.? you could always put the VOM on the 1X scale (or diode), block open the points and watch the rise time. that should tell you if it has a cap connected.

at this point I wouldn't worry to much, just keep a keen eye on the points for burning.

[charbot]

Dont have an analog meter but Ill try the diode setting next time I have it open.

even though the coils test as shorted to ground and the condensers are invisible! - seems like id have some major issues even running if I didnt have condensers in the circuit , so I guess everything is working. Probably should leave this one alone and find something else to fix.

Thanks guys