SOHC.co.uk Forums > CB500/550
idle jet differences , 069's
fogrider:
Looking at carb kits for sale for the CB550f, there seems to be two types : an air screw that is solid paired with a long idle jet, then a hollow air screw with a side hole in it as well with a smaller bodied idle jet. My 1976 F1 has the solid air screw pairing and as I cannot get rid of the huge bogging down just above idle, I wonder if they are the right ones ?
I have done all the usual things - points/dwell, ignition timing, advancer OK, fuel level Ok and it idles well and reacts to air screw changes. It's not too bad after several miles and warmed up, but from cold it just won't play off idle without full choke but then, after clearing up and revving OK it ,obviously, goes way too rich.
The carbs have been stripped and cleaned ( they were OK as it happens ) but I seem to be missing something, probably obvious !
Any pointers very welcome.
Regards all, Terry.
deltarider:
The solid type airscrews and the long jets are the right ones for your model. Genuine Keihin jets have the star like K logo stamped. You may want to consult the overview attached. Generally speaking the chokes will be fully opened again before departure but you will need a raised idle for the first two km. Some keep the grip twisted for this, as suggested in the Owner's manual, others use the big idle adjuster which they readjust at say the second traffic light. Do not expect a good acceleration from a stop with the throttle yanked open more than halfway.
fogrider:
That's excellent, clears up the thing about hollow tip and solid. It runs as though a smaller cutaway would be better but they're original and in good order. Honda knew best I'm sure.
I spotted a reference to fuel levels later last night, someone had checked with a clear tube - 3mm below fuel bowl top.
Might have a look at that out of interest.
Thanks Deltarider, very useful info.
deltarider:
To verify correct fuel levels, you may want to use the simple method.described here: http://forums.sohc4.net/index.php/topic,185754.msg2151647.html#msg2151647
Trigger:
--- Quote from: deltarider on May 28, 2021, 06:50:29 AM ---The solid type airscrews and the long jets are the right ones for your model. Genuine Keihin jets have the star like K logo stamped. You may want to consult the overview attached. Generally speaking the chokes will be fully opened again before departure but you will need a raised idle for the first two km. Some keep the grip twisted for this, as suggested in the Owner's manual, others use the big idle adjuster which they readjust at say the second traffic light. Do not expect a good acceleration from a stop with the throttle yanked open more than halfway.
--- End quote ---
The information is incorrect: keihin air screws can come with or without holes ;)
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