Not so fast! I may have jumped the gun
Well, when I reported that "it worked" after switching the breather cap with the closed cap, I simply started the bike and revved it a little, but I never took it out.
After finishing up several other things, I finally took it out. It runs better than ever below half-throttle. Amazing pull. But when I get above half-throttle it sort of dies out like the fuel-to-are mixture is way wrong. I didn't try it too much this way because I didn't want to foul or burn the plug.
As you know, the secondary carb is supposed to kick in above half-throttle, exactly where the problem is happening. I checked all of the linkages and action of the butterfly flapper and needle/plunger, and it seems to be working correctly. But since I didn't study this in detail before my carb tear-down and cleaning, I am not sure if what seems to me to be correct is actually correct.
I can try certain things and take photos that you experts suggest if you will be kind enough to help me troubleshoot this.
Let me start with a question. How does the fuel get over to the secondary carb? In the attached diagram it shows two connecting tubes from the primary carb to the secondary carb which I have circled in red. In reality there is only a place for one (the lower one) connecting tube to hook into each carb. There is either a mistake in the diagram, or the diagram is a generic one for the several models that this exploded view covers. I am concerned that perhaps my secondary carb is not getting fuel.
Thanks,
Tom