Topic: 1980 cb650 running rich.

[Jetpilot1]

1980 cb 650 custom, stock except for 4 into 1 exhaust.  Running rich.  95 main jets.  Float level checked to 12.5 mm, not leaking, holds 5+ psi all day.  Going to try clear line fuel bowl level check, but how high should the fuel go in the line?  Mixture screw set to 1.5 turns.  I noticed no o ring on idle needle - any chance this is causing richness?  Going to 90 main jets and fixing o ring issue.  Any ideas?  O yeah- stock intake box.

[minimo]

Running rich at idle or on load?

Main Jets are only affected at mid throttle so changing that will likely make minimal if any change if you are experiencing a rich condition at idle.

This chart has always been helpful:




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[Jetpilot1]

Seems rich across the board....

[bryanj]

There was a bulletin from Honda about 650 and drilling airbox but cant remember which model and dont have access to by bulletin book

[TurtleSnifferII]

There was a bulletin from Honda about 650 and drilling airbox but cant remember which model and dont have access to by bulletin book

Is it this?

[bryanj]

Thats one but my aged memory tells me there is another