Topic: gas in the exhaust

[pablo78cb550]

ok,
1978 CB550K
fresh engine rebuild,
pod filters,
4-1 exhaust,
jetted by suggestion from a garage to 115? (to run 4-1 exhaust with pods.)
read up a little more re-jetted to 100 then 98
then 92.
still spitting gas out the back. WTF?
plugs are wet with gas.
float levels? anyone ever adjust floats in a 78 CB550K? where do you measure from?
which edge? front? side? back? middle? these are not round floats!!(damn clymer) pics would help.
is it the points? it idles fine. but it bogs when i try to give it gas.
another thing, who the hell designed the balancing screws on the 77-78 carbs?
on the inside? what about air leaks down the slide when you're making an adjustment??

1. should i keep backing out the air mix screws?(out to 3 turns)
2. try adjusting the points (again).
3. needle position? i haven't taken it apart yet ( it would be first time completely taking apart the carbs to change needle setting.)

help.

[BlindJoe]

You should use  105 mains and the stock needle position. Do you have your valves adjusted correctly. Float height should be measured from the edges of the bowl that run parallel to the frame, to 12.5 mm

[750goes]

I think your carbs are adjusted for mixture by - turn in to make lean - turn out to make rich...
what model of carbs are they (should be stamped on the side nearer the inlet manifolds)..

do one at a time
screw each mixture adjuster in slowly until your revs rise to the highest level per carb...then drop your main idle adjustment screw (for all four cabrs) back to a comfortable level....
go to carb 2 and do the same
then carb 3
then carb 4

do it all again until when you turn the mixture screws in it starts to drop revs and then you need to back that carb screw out about 1/4 turn...it will get you pretty close....
do this on all 4 carbs - remembering to adjust your main idle adjustment along the way - you will soon learn to hear the difference in revs and you can verify by looking at your tacho as well..

let us know the model carbs - that will help a lot...

[750goes]

look at this specification sheet - it should help with a standard set up - at least you should know what it was at sometime in the past...


http://www.motorcycleproject.com/motorcycle/text/specs.html

[pablo78cb550]

I think your carbs are adjusted for mixture by - turn in to make lean - turn out to make rich...
what model of carbs are they (should be stamped on the side nearer the inlet manifolds)..

do one at a time
screw each mixture adjuster in slowly until your revs rise to the highest level per carb...then drop your main idle adjustment screw (for all four cabrs) back to a comfortable level....
go to carb 2 and do the same
then carb 3
then carb 4

do it all again until when you turn the mixture screws in it starts to drop revs and then you need to back that carb screw out about 1/4 turn...it will get you pretty close....
do this on all 4 carbs - remembering to adjust your main idle adjustment along the way - you will soon learn to hear the difference in revs and you can verify by looking at your tacho as well..

let us know the model carbs - that will help a lot...

the carbs are the 78 model carbs. NOT covered in the clymer manual.
please confirm"air mix screw turned out =richer, turned in =leaner?"
i was sure with ALL my other bikes it was the opposite.

[City Boy]

I think you will find as a general rule,a mixture screw in the side of the carb body will be an air screw,in to richen,out to lean.A screw installed vertically at front of float bowl is fuel screw,in to lean,out to richen.Fuel screws are usually found on CV type carbs.      Rock On