CA77 Dream running GREAT! ... Until it gets HOT.

Bob750 · Post by **Bob750** » Mon Mar 16, 2015 10:34 am

We've only ever put Chevron 91 octane or Mobil 91 octane in it. We use premium because it remains stable longer than regular and has less, if any, ethanol. And in Southern California I believe the stations are now serving the Summer Blend, which is less adulterated than the Winter Blend. I run the same gas in my CB750 and have no issues. So I doubt it's the fuel we're putting in.

As for electrical. I suppose extreme heat could alter the operation of a condenser. But the coil doesn't get much heat inside the gloss white side cover, shaded by the rider's thigh; so it's not likely the coil. But you're the second to mention the condenser as something to consider. I could put the "shop hair dryer" to it before a ride to see if it triggers the symptom sooner. And I do have a spare condenser... And I'll open the side cover and feel the coil if/when the engine acts up and see if it's unusually hot, just to be sure. Or maybe I'll run around with the side cover off...

mike in idaho wrote:If it's not a carburetion issue, maybe it's a fuel related issue. Have you tried a different grade of gas? Maybe some ethanol free blend(if you can find it). Maybe it's electrical, do you have a way to heat up the coil/condenser(with a heat gun or a hair dryer) to see if it acts up?

Bob750 · Post by **Bob750** » Mon Mar 16, 2015 11:05 am

Okay. I've learned over on my restoration thread, where we're also discussing this bad-when-hot issue, that the classic condenser failure is due to heat. So mike from idaho's suggestion has been corroborated. This is encouraging.

We may have to move this thread to the Ignition section... ;-)

I'm headed out to the garage.

48lesco · Post by **48lesco** » Mon Mar 16, 2015 3:57 pm

Bob

Those plugs look a little dark, I'd use the D6's. That's all I use in the two Dreams I ride and never a problem. The D6's will clean up at speed, I think any plug would foul a little after 10 minutes at idle.

If you have an inductive timing light, see if there's a difference in the strobe between hot and cold. Also see if the points are arcing to indicate a bad condenser and make sure the condenser case is grounded well in its unfortunate location at the top of the head.

Another component that can go south when hot are resistor caps, those new?

Bob750 · Post by **Bob750** » Mon Mar 16, 2015 9:14 pm

Thanks for the replies, everybody.

I think it was just really dirty points. I cleaned the points by dragging a folded piece of 600 grit wet-dry sandpaper spritzed with 'Lectra-motive cleaning spray through the closed contacts; then I followed that with a business card wetted with contact cleaner. I also repaired a couple of wiring connections that were needing it (one being the wire from the harness to the condenser). Then I went riding.

I rode "hard" for 25 miles for a period of one hour without turning off the engine. Up hills. In stop and go traffic. Wide open throttle on PCH. Heavy acceleration at most lights and stops. Whatever I could do to get it HOT.

After my butt became too numb to continue, I pulled into the garage and let it idle for a few minutes. Not once did it develop the business shown in Video 2 above.

I guess I need to clean these points every 500 miles. I don't think the condenser is the problem. But if it ever does fail, I have one on hand.

Look at these:

48lesco · Post by **48lesco** » Tue Mar 17, 2015 7:46 am

Those look perfect how I like my marshmallows. Glad you got it sorted out.

LOUD MOUSE · Post by **LOUD MOUSE** » Tue Mar 17, 2015 8:15 am

If you did a full rebuild you may want to readjust all parts which have required clearances.
With cold engine adjust all valves. (they be tight now)
Clean and adjust points. (the phenolic area which contacts the points cam will wear in and close the gap and change the "F" timing).
Worth a try I guess. ....................lm)
OH. And leave the gas cap loose.

mike in idaho wrote:If it's not a carburetion issue, maybe it's a fuel related issue. Have you tried a different grade of gas? Maybe some ethanol free blend(if you can find it). Maybe it's electrical, do you have a way to heat up the coil/condenser(with a heat gun or a hair dryer) to see if it acts up?

Bob750 · Post by **Bob750** » Tue Mar 17, 2015 12:41 pm

Gas cap loose to prevent vacuum? Our cap is perfectly clean and and vents very well--too well, judging by the top of the tank on a hot day... ;-) I'll check the valves again, but just cleaning the points cleared things up nicely. Thanks, LM! Your valvetrain and head work you did for us is, well, still awesome.

LOUD MOUSE wrote:If you did a full rebuild you may want to readjust all parts which have required clearances.
With cold engine adjust all valves. (they be tight now)
Clean and adjust points. (the phenolic area which contacts the points cam will wear in and close the gap and change the "F" timing).
Worth a try I guess. ....................lm)
OH. And leave the gas cap loose.

mike in idaho wrote:If it's not a carburetion issue, maybe it's a fuel related issue. Have you tried a different grade of gas? Maybe some ethanol free blend(if you can find it). Maybe it's electrical, do you have a way to heat up the coil/condenser(with a heat gun or a hair dryer) to see if it acts up?