Last fall I rebuilt the carbs on my 1974 CB550. Because of the 4 into 1 exhaust and velocity stacks the bike never really ran right. From idle to 1/4 throttle performance was ok, but acceleration between 1/4 and 1/2 throttle was poor. Additionally, cruising in 5th gear at 5000 rpm the bike would surge or hunt (felt like it was running out of gas).
A plug chop test revealed normal mixture at less than 1/4 throttle, 1/2 and full throttle tests revealed a lean mixture. Here's the process I went through that seemed to work:
1. Adjusted cam chain tensioner
2. Adjusted valves
3. Set dwell (48 degrees)
4. Adjusted timing
5. Replaced slow jets (went from 38s to 40s)
6. Drilled out the main jets (100s) with a #57 drill (makes the jets 1.09mm)
7. Added 2 in line fuel filters and new fuel lines
8. Balanced and synchronized the carbs
9. Set the main jet needle at clip position #3 (Second richest)
Results smooth acceleration through 8000 RPMs - smooth idle at 1000 RPM (before these adjustments idle was very rough below 1500 RPM).
I also want to thank everyone who made prior posts on these topics - I'm sure your tips ended up saving me countless hours of trial and error testing before I would have had the bike dialed in.
Now if it would only stop raining here in Southern Connecticut.
