<p>That pop out the exhaust is unburned fuel lighting off down in the tuner. At idle you have the most crankcase vacuum and the least airflow, so a lean hole will pop there and nowhere else. That is why it runs fine at speed.</p><p><br></p><p>Timing is not something you can set on that motor. The CDI does it. A sheared flywheel key would make it run bad everywhere, not just at idle. So I would put timing at the bottom of the list.</p><p><br></p><p>The seals. You said no obvious damage, but a lip can be hard and still look fine. It only leaks when vacuum is highest, which is idle. Pull the plugs and read them before anything else. If one is wet and the other is dry you are chasing one cylinder, and then it is that seal, that reed block, or that carb.</p><p><br></p><p>How did you clean the carbs? Ultrasonic does not always get the idle circuit. The fuel goes through drillings smaller than a hair and the brass plug hides the passage. I have had to rod those out with a torch tip cleaner and then watch carb spray come out of the right hole before I believed it. Check where the mixture screws sit too. About a turn and a half out from lightly seated is the book starting point on these twins, verify it against your manual.</p><p><br></p><p>And I agree with racerone on the plates. If the linkage holds them open a hair at idle the idle circuit is out of the picture and it will be lean no matter what you do with the screw.</p><p><br></p><p>What compression numbers do you have, and are they even across both holes? What do the plugs look like, cylinder by cylinder? thanks</p>
