Topic: CB550F really bad MPG issue

[PatrickZ]

Hello good people of SOHC,

I have a completely rebuilt 1976 CB550F that's been modified as a cafe racer with Dyna coils and ignition, no airbox, and new electrical system. Engine / carbs were rebuilt at as well by the garage I worked with.

There are a few issues I've observed that may be related that are just killing me now:
- Bike has really low MPG. I'm getting ~56 miles before hitting reserve on my 3 gallon tank, that's <20 mpg for 80/20 city/hwy riding.
- Idle jumps ~1500 rpm between being in gear vs. neutral
- Bike feels like it's struggling when accelerating from stop in first gear, I really have to crank it up to 3000 rpm before I let out the clutch

My hypothesis is that I'm running extremely fuel rich and need to reset the mixture on the carbs to much leaner. But I wonder whether that alone can cause a drop in MPG from ~35 mpg to <20?

Thanks in advance for your help!

Patrick

[robvangulik]

Did you read the "so you want to run pods" topic?
What size jets are in there, and what kind of exhaust?

[Scott S]

http://forums.sohc4.net/index.php/topic,182280.0.html