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1969 CA77 Condenser

Points Based Ignition | Electronic Ignition Upgrade
quidger
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Joined: Wed Sep 22, 2010 7:05 pm
Location: Omaha, Nebraska

1969 CA77 Condenser

Post by quidger » Thu Aug 07, 2025 4:13 pm

I’m trying to change out a condenser that I think is bad on my 305 dream. I have unplugged the existing condenser that I think is bad and I am trying to replace it with a condenser from a CL 77. It seems like a simple conversion. I have unplugged the wires from the CA 77 connection I think is bad and I temporarily mounted the CL 77 older condenser to the to the motor case and then I took two of the four connecting wires that are on the CL 77 condenser and hook them to the coil and to the ignition points. But I have no power no 12 V power at the points. I can’t understand why I’m not getting power. Can someone look at the video that I have posted the link to for Dropbox and tell me what they think. I would appreciate any help.

https://www.dropbox.com/scl/fi/7ax0c5c8 ... wwrgm&dl=0
S90 / CB550 / CA 77 Dream 305 / Yamaha RT2 360

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Muddy
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Location: Sunshine Coast, QLD, Australia

Re: 1969 CA77 Condenser

Post by Muddy » Thu Aug 07, 2025 6:29 pm

G'day quidger

Nice looking Dream you have there.

Points and electrics are definitely to my speciality, but I'll try and help where I can. I'm also totally unfamiliar with the CL77 condenser wiring, but it does appear to have 4 wires and not 2 wires like the Dream has.

Do you have a wiring diagram for the Dream and also an electrical tester or multimeter? You will need all these.

Is it possible that some of your wiring has got confused between swapping between the different condensers?

Here are some suggestions.

Unplug the condenser.

The C77 wiring diagram I have shows a black connector providing power to the coil. There looks to be a black female connector in the main harness that is unplugged on your bike. Using a tester, check if this is getting power with the ignition switched on and it should have no power with the ignition switched off. If this is a switched power supply, it should go to the black cable, male terminal connector on the coil.

If it is a standard coil, there should be a green wire coming out of the coil. Your clip seems to confirm this. Test this wire and make sure it switches off and on with the ignition switch also. If it does, it means you have the coil connected properly and power to it.

Now plug the original green cable into that green coil terminal and connect that to the points. Again test and you should have a switched power supply to the points. This is the very basic fundamental circuit that is required to get the coil to work and provide spark to the spark plugs. The points just are a simple switch that turns power off and on to the coil that produces spark at the plugs.

My understanding of the condenser is that it just connects in parallel to the points and “smooths” the power supply to the points and reduces arcing on the points. The condenser is not essential to the testing of the circuit so you can leave it out for testing.

Once you have the basic circuit in and testing OK, you can then move on to the condenser issue.

What makes you think the original condenser is an issue?

Good luck and let us know how you get on.

Regards

Muddy
Thanks.

Regards

Muddy

'64 C72
'63 C72

quidger
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Posts: 59
Joined: Wed Sep 22, 2010 7:05 pm
Location: Omaha, Nebraska

Re: 1969 CA77 Condenser

Post by quidger » Thu Aug 07, 2025 8:04 pm

Hey Muddy,

Thanks for chiming in. I think the problem is the condenser because coil test good, compression test is solid, carburetor disassembled and ultrasonic cleaned, timing reset. Bike was running fine but as soon as it got well warmed up, it would start to stumble and eventually die. Several people said that behavior, losing its mojo when the system is hot would often indicate an electrical failure. I lined at the points plate while turning the motor over in a dark garage and it looked like there was arcing of the spark which I understand points to a faulty condenser.
It was explained to me that the CL 77 points are basically like a double set of CA 77 points .in other words if you were to split just take two of the four wires off of the CL 77 and hook it up to the CA 77 you would basically get a single point system .
The existing CA77 condenser is almost impossible to access and remove without dropping the motor. Not up for that if I can avoid it.
So I mounted the CL 77 condenser on the motor casing for ground and then I simply removed the wire that goes to the points from the existing condenser and I replaced it with the same type of wire that comes from the CL condenser. And then on the other cloth wrap male plug power wire that goes to the coil I joined the female black wire plug from the coil. I had to make a little green jumper wire with female connectors on both ends to join what I believe to be the power to coil wire.
Sorry for the long explanation but it seemed to be the logical way to hook things up. Apparently, I have a misstep. I am only dealing with 2 wires and grounding the condenser so not a bunch that can go amiss. Thank you for helping me solve.
S90 / CB550 / CA 77 Dream 305 / Yamaha RT2 360

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Muddy
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Joined: Wed Mar 30, 2011 11:03 pm
Location: Sunshine Coast, QLD, Australia

Re: 1969 CA77 Condenser

Post by Muddy » Thu Aug 07, 2025 9:55 pm

G’day quidger

I understand your thought process and agree it could be an electrical issue. Coils can also fail as they get warmer, as can spark plugs and plug leads.

Anyway back to the problem at hand. I’ve done a bit of research on the CL77 condenser and it is indeed just a double condenser. One half of the CL77 condenser should be wired in just like the Dream condenser. I may be wrong, but it looks like you have the condenser wired in series to the points, not in parallel. If this terminology is confusing or incorrect, please let me know.

I’d go back to scratch and make sure you have power to the points without the condenser in circuit. Then we can get the condenser put back into the circuit for you to check.

See how you go.
Thanks.

Regards

Muddy

'64 C72
'63 C72

quidger
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Location: Omaha, Nebraska

Re: 1969 CA77 Condenser

Post by quidger » Fri Aug 08, 2025 6:31 am

Hey Muddy,

I do not understand the in series vs. parallel terminology. I think it’s important that I grasp this concept before I proceed.
Thank you.
S90 / CB550 / CA 77 Dream 305 / Yamaha RT2 360

quidger
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Posts: 59
Joined: Wed Sep 22, 2010 7:05 pm
Location: Omaha, Nebraska

Re: 1969 CA77 Condenser

Post by quidger » Fri Aug 08, 2025 8:12 am

Here’s what I Googled:

Still don’t understand how the wiring can be configured differently.

What is the Difference Between Series and Parallel Circuits ...
In series and parallel circuits, the primary difference lies in how components are connected, affecting voltage and current. Series circuits have components connected end-to-end, forming a single path for current flow, while parallel circuits have components connected side-by-side, creating multiple current paths. Wiring a motorcycle's points will often involve both series and parallel connections to distribute power and control various components.
S90 / CB550 / CA 77 Dream 305 / Yamaha RT2 360

quidger
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Posts: 59
Joined: Wed Sep 22, 2010 7:05 pm
Location: Omaha, Nebraska

Re: 1969 CA77 Condenser

Post by quidger » Fri Aug 08, 2025 9:27 am

Okay. I had totally connected the replacement condenser incorrectly.
It is now wired exactly as the original one was wired.
Still no power at the points. Both the black and green wires coming from the coil read 12V.
What I assume are parallel electrics -horn, starter motor,- are working fine.
S90 / CB550 / CA 77 Dream 305 / Yamaha RT2 360

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