1969 CA77 Condenser

[Muddy]

G’day quidger

The Dream engine has a 360-degree firing, wasted spark, engine configuration, meaning that both spark plugs fire at the same time, with one spark being “wasted” on the top of the exhaust stroke. Hence the need for only one set of points and one coil for the 2 cylinders. Both pistons travel up and down in unison, however one piston might be on the compression stroke while the other is 360 degrees opposed on the exhaust stroke.

Are you getting a good strong spark at both spark plugs with the new coil?

All 4-stroke engines are pretty basic. To run they just need fuel/air, spark & compression - all at the right time and in the right quantity. Given the bike has been running and presumably the valve timing has not changed, then the valve timing is probably correct as validated by the compression being OK. However, if there is any doubt, please check it.

That leaves spark and its quantity and timing, plus fuel and its quantity and timing.

If you have a good strong spark on both plugs at the same time, then maybe check that the spark is timed correctly.

There is some great info here:

viewtopic.php?f=22&t=5750

Keep at it, you’ll get there.

[Muddy]

Also some great tune-up and timing info here:

https://www.honda305.com/cb77_700/cb77-716.htm

Good luck.

[quidger]

Thanks for all of the information, Muddy.
Now I have an overflowing carb.
I’m thinking possibly a worn float valve needle tip & seat.
Brass overflow tube pressure tested and no leaks, cracks.
Floats tested , no leaks.
So I’m going to order new OEM float valve& seat but there’s confusion with Honda part #.
I’m going to post on the forum page and see if anyone can chime in.

[quidger]

Hi Muddy.

Still no luck getting it started. I adjusted the floats about a mm and that cured the carburetor over flow issue.
Good spark , timing is right on, 12V at the points.
I need to make sure I am hooking up the CL 77 condenser properly.
First, there are basically 2 single CA77 condensers enclosed within the one CL 77 condenser.
I should be able to make sure I have the correct 2 wires from each side of the CL77 condensers by testing for continuity between the square points connector and the male bullet connector that plugs into the green wire. If am testing 2 wires that are not compatible, I will get OL reading. Is that correct?
If only one of the two CLL 77 condensers test good, does that mean if I connect the two good wires to the points and green power wire that the connection of the good side of the coil will be affected negatively by the bad side and will be ineffective in performing its job.
At this point, I think the issue has to be the condenser.
Good spark
Good compression
Fuel
Timing good
Not sure where else to look.

[Muddy]

G’day quidger

You’ve made more progress - which is a good result.

One final check, that you may have already done, but just in case…

As the points just start to open and the static test lamp just comes on, the line on the end of the camshaft at the points, must be facing downwards. The attached photo shows this. If this is incorrect, the valve timing will be incorrect. If not already done, please check and confirm this is OK.

Now check the 4 valve tappet clearances to ensure nothing is wrong there (unlikely, but possible).

Remove the air cleaner and air hose from the carby.

Now make up a jumper wire to bypass the condenser. Connect the green wire out of the coil to the screw terminal on the points and leave the condenser out of the circuit. Check the points timing again. With the “F“ mark on magneto rotor aligned with the pointer of the crankcase, the static timing light should just come on and the line on the crankshaft at the points should be facing downwards (as shown in the photo).

Now we know that the engine valve and points system is timed correctly and we can try and connect the condenser.

Try the original CA77 condenser first. After it is connected, try the static timing again – make sure it is correct.

Check and ensure you have a good strong spark at both spark plugs while cranking the engine over and the spark plugs out of the engine and grounded against the motor.

If you have good spark, the valve and spark timing is correct and the carby is OK, the engine should start. These engines are “cold” engines and generally need plenty of choke (enricher). If it still does not start, check the spark plugs to see if they are wet or dry. Wet means it is getting fuel, dry means no fuel.

Put the plugs back in and try some starting ether in the carb intake while cranking the engine. It should start. If not, then I’d say something is incorrect with the above procedure so recheck and confirm.

If you get spark at the plugs without any condenser, but no spark with the CA77 condenser we can try the CL77 condenser next. First, just let us know how the above goes.

Please let us know how you get on.

[quidger]

I haven’t checked the line on the camshaft. Wasn’t aware of this concept.
Also, when I tested for spark I used a test light device that has a spark plug cap on one end that attaches to the plug and the other end has a probe that goes in the plug cap and a glass bulb in the middle. When I kick the bike over the spark is visible in the glass window. Is that an adequate test for checking for spark. Or should I remove the plug and ground on the cylinder.
I’ll get working on this tomorrow. Thanks for sharing your knowledge.

[Muddy]

G'day quidger

The spark plug test device should be fine, especially if the spark plugs are gapped, clean and new. But in this case, build your confidence first. Please try without the tester and the plugs grounded on the motor. Ensure you see a good strong spark at both of the spark plugs. Once you are confident that you have a good strong spark at the spark plug, use the tester.

Do you have a good spark with the CA77 condenser in the circuit?

Let us know how you get on with more testing.