Topic: 550 pilot screws

[zoeyk9]

The Clymer manual for my '78 550 says that the pilot screws are AIR screws, which meens that I turn them OUT to weaken the mixture. But if they are pilot screws wouldn't turning them out richen the mixture? What is correct?

Zoeyk9

[speedy gonzalais]

i think out is more in is less

[zoeyk9]

Well Didds, I don't think my wife would agree with that!

Do you meen more fuel or more air?

Zoeyk9

[dnewman417]

If it is a 1978 CB550K, then the screws are "idle mixture screws."  Turning them in richens the idle mixture and turning them out leans the idle mixture.

[Brian G]

If it is a 1978 CB550K, then the screws are "idle mixture screws."

Newbie question here . The carburetors in the Clymer manual show the screws on the side of the carb body. On the bike, however, there are no screws on the side. On the K4, are we talking about the brass knurled screws mounted vertically underneath the front of the floatbowl on the engine side?



They were all open about 2 turns, and the bike seems to be running lean - takes forever to warm up and spits back through the carbs at idle. I'd say the throttle response is a bit flat as well, but I've only owned the bike for a couple of weeks and have nothing with which to compare it.

It is fitted with what I believe to be a MAC 4 into 1, and the P.O. said he'd made no carburation changes whatsoever. Can anyone tell me if installation of this type of exhaust requires jet/needle/cutaway adjustments as a matter of course?

On another matter, in a response to my introductory posting a few weeks ago, it was mentioned that people here like pictures!, so here are a couple. No shortage of things to work on this coming winter 

Hopefully this isn't seen as 'hijacking the thread' 
Best Regards,
Brian

[apoji187]

2 and a half out is about right, but you should really crack open those carbs and see if the idle jets are clean and check that float height.

[Brian G]

Turning them in richens the idle mixture and turning them out leans the idle mixture.

2 and a half out is about right, but you should really crack open those carbs and see if the idle jets are clean and check that float height.

They were all open about 2 turns....

Yikes  ! So the screws were already 1/2 a turn rich and she stills spits! Guess a carb overhaul will be the first job this winter. I'd better do some plug chops before the snow and ice arrives too. Is the needle generally raised a notch and/or go up a size on the main jets when changing from a 4 into 4 to a 4 into 1? If so, I might as well do that while they're apart....

Thanks