Hmm.. Interesting. Sounds like the problem should have been expected then. I've got a 65 jet kicking around that I might try out. I need to make an intake as well. I wonder where I can find 15mm ID tubing?
I pulled off the side panel and filter a little while ago, but it didn't make much of a difference at all.
Strangely it picked up when it was choked. Does that make any sense?