Condenser problems

[Guest]

I still have the original points ignition on my '77 GS750. About a month ago it started missing on 2-3 and I eventually tracked it down to a bad condenser on that set of points...with points cover off and bike running in dark garage there was much sparking at 2-3 points.

So I put in all new points and condensers that I got from Z1. Bike ran great. Yesterday I stared it up and it was missing on 2-3 again. Same test: a bit more sparking at 2-3 points so I put the leftover good OE condenser and the bike runs good again. But for how long?

is there some condition with coils or spark plugs or anything else that could toast condensers?

thanks in advance
Brian

[JTGS850GL]

If it were me, I'd covert to electronic ignition and be done with it. The Dyna-S kits work great. You'd need the DS3-1 or DS3-2 kit depending on which advance plate is installed. There should the letters "KD" or "ND" stamped on the advance plate. If it's "KD" then you need the DS3-1. If it's "ND" then you'll need the DS3-2.

[canuckxxx]

Yes, i probably will go that route. I have the ND style points. Are the green Dyna coils (3 ohms I think) compatible with the Dyna S.

Paid $45 for the new points and condensers and now one of the new condensers is gone so that still bugs and would still like to figure that out. Might be awhile before I round up the $300 I figure it will cost for Dyna S, green Dyna coils and plug wires.

thanks
Brian

[canuckxxx]

Yes, i probably will go that route. I have the ND style points. Are the green Dyna coils (3 ohms I think) compatible with the Dyna S.

Paid $45 for the new points and condensers and now one of the new condensers is gone so that still bugs and would still like to figure that out. Might be awhile before I round up the $300 I figure it will cost for Dyna S, green Dyna coils and plug wires.

I guess the first thing to check is the primary resistance of each coil. Should both be about 5 ohms I think.

thanks
Brian

[JTGS850GL]

The stock coils and the green coils have the same 3 ohm resistance and are both compatible with the Dyna-S ignition.

[canuckxxx]

OK, I checked resistance to ground of primary side of both coils. Got the same 4.7 ohms for each. Might have just been a bad new condenser. If I had a spare condenser to carry with me I could easily swap it in in about 10 minutes if I really took my time.

All you guys out there who have swapped out your points please sell me a condenser for cheap.

thanks
brian

[JTGS850GL]

Dyna-S is no where near $300. They can be picked up for under $140 all day long. Shop around and you can find them for less.

[posplayr]

I had an electrical problem I chased for months ; my old boss (in HS I worked at a gas station after school) showed me that I had bad plug wires and the spark was bouncing off the high impedance and arching at the coil. I would strongly suspect if the coils were arching your are probably arching at points also. The opposite might well be true as also. New ignition will not help and highly unlikely that the points. are the problem. My suggestion is to fix it before moving on.

[canuckxxx]

I had an electrical problem I chased for months ; my old boss (in HS I worked at a gas station after school) showed me that I had bad plug wires and the spark was bouncing off the high impedance and arching at the coil. I would strongly suspect if the coils were arching your are probably arching at points also. The opposite might well be true as also. New ignition will not help and highly unlikely that the points. are the problem. My suggestion is to fix it before moving on.

So are you saying that there might not be a good connection between high tension wires at the coil so high impedance? Interesting. I'm pretty sure I have the OE coils and plug wires...they still have the metal covers at the plugs. I guess the fix then would be new plug wires, right?

i have looked in at the plug wires in a dark garage with engine running and didn't see any arcing but maybe the arcing is inside the coil-to-wire boot.

Would I use solid copper core plug wires? Maybe I could redo the connection with existing wires.

thanks
Brian

[canuckxxx]

Just went out to the garage and measured the resistance between 2 - 3 and 1 - 4 plug leads; 1 - 4 was 32K ohms, 2 - 3 was infinity so no metal to metal connection. 2 - 3 is the one I have been having trouble with.

I think you've nailed it posplayr. I might try redoing all the cable ends. I think there is a writeup at Basscliff's website on how to do that.

Thanks a lot
Brian

[850 Combat]

Wow.I learned something there too.

[canuckxxx]

OK so this evening I took the tank off and tried to measure the resistance across the coils. Got the same result as before 32k ohms across 1-4, infinity across 2-3. I remembered the last time I ran the bike #2 pipe was not getting very hot so I pushed down on it's plug cap and got a little shock. So I screwed the cap off of #2 and tried to measure the resistance through it. Got infinity across the cap. Unscrewed the resistor inside and some very corroded pieces fell out. So cap is toast.

Then I took the rest of the plug caps off and checked them. There was one other bad one and the other two had 10k ohm resistance through them. Measured the resistance through both coils now with the plug caps removed. I got about 12k ohm on each.

So I figure the coils and leads are OK but I need to, at least replace those two bad caps. Would like to find the same OE looking caps like the ones in the picture. Notice that the 2-3 caps are longer then the 1-4 caps.

Any ideas where a guy could get new caps?
Thanks
Brian

[canuckxxx]

Found these caps at Z1. They look very similar to OE. Says they are resistor caps but don't know if they would be 10k ohms of not but does it matter? Anybody here use these?

http://www.z1enterprises.com/ItemDetails.aspx?itemDescription=NGK+Spark+Plug+Cap+12mm+%26+10mm+102+degree+XD05F&item=TU38-1006

http://www.z1enterprises.com/ItemDetails.aspx?itemDescription=NGK+Spark+Plug+Cap+12mm+%26+10mm+120+degree+VD05F&item=TU38-1008

[canuckxxx]

Here is another thought. Do you need the cap resistance for it to work right or is that stop radio interference?

Here is a picture of one of the bad caps with the part that screws in (that contacts the spark plug end) and the resistor pieces that came out. Why couldn't I just replace the resistor parts with a piece of copper wire? Would at least get me by until the new caps arrive from Z1. Supposed to be nice weekend coming up.

Thought, comments?
Brian

[JTGS850GL]

Quit being so cheap and fix it with the right parts. A brand new set of 4 caps will set you back around $20 and last another 30 years. Trying to fix those caps is just a waist of time.