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Doms CB550F1 project
K2-K6:
The absolute airscrew setting has always been part of adjustment scheme in reality, rather than solid set and forget.
With variation likely on component now in comparison to production line original, then highly likely that set point is going to be different.
Bore of jet, bleed holes, airflow passages, air filter performance, piston ring sealing, fuel burn characteristic, ethanol inclusion (contains oxygen over and above no e types) will all contribute to a setting that may be different to "book" value originally given.
The cleaning of the jets and air passages are also a scource of variance too.
Establishment of a set for what you've now got in place should effectively accommodate these.
Fuel injection system do exactly this now, with more or less the same methodology as Honda originally published in their manuals, just automatic in itself via ecu programming, built in sensors etc.
Like these carbs though, if the sensible adjustment fails to yeald a competent combustion before reaching the end of logical steps available, then it'll usually throw emissions/check engine code and warning to request further work in establishing what is the real cause of going out of range.
DomP:
Thanks Nigel, that's one hell of a reply. Carbs are coming off this week if I get a chance so that I can eliminate my bench sync from the equation
DomP:
Is there a way of testing if my standard Keihin pilots (38) are within spec and not worn or over cleaned to a point they are now significantly larger?
McCabe-Thiele (Ted):
I believe the concensus is that the screw adjustment range will compensate for normal wear.
That said I know one member used one 38 and four 40 jets to avoid a rich running cylinder. The air screws for the 500 are a very different design to the 550. My 500 was fitted with the 550 brass solid flat ended screw. Courtesy of Ken I have fitted the correct ones that are hollow with side holes.
DomP:
That confirms my thoughts Ted, I suppose it would run richer as the pilots wear meaning screws out further to compensate.
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