Hi , Matthew . I had the exact same problem as you. My temporal solution was indeed to place a clip in the tube of the power jet, thus fully restricting it and fitting a 210 main jet. Even then, on full throttle I was running on the rich side, which made the engine to bog and not go above 8k rpm.
I managed to fix it some days ago. I will make a post with pics on the whole procedure sometime around the next month when I will have the time, but here’s some things I did to look into:
Fully clean the carburetor body and jets using an ultrasonic cleaner.
Replace all the O-rings with new ones.
Replace the needle valve with the seat with brand new ones.
Adjust the float height to the Hayens manual specifications.
After the rebuilt I went from running rich and having hesitation on fast openings of the throttle to actually running a tiny bit lean with crisp response .
*The lean is probably due to the 210 main jet I’m using instead of the factory 240 one. *
If you haven’t changed any of the jets, I think the above steps will help you.
Also be sure to make a plug chop using a new spark plug to verify that you are not running overly lean or rich before and after the rebuild .
