Honda-SOHC

Since governments have mandated alcohol petrol blends, we have a problem. How could they is another question. Ethanol will deteriorate everything that was not made with this compatibility in mind. it basically eats rubber, plastic, fiberglass, etc. Carb 1+2 fed from line 1 and carb 3+4 fed from line 2 both from the dual outlet petcock. I suspect you have little rubber bits blocking the idle jet, which is a lot smaller orifice than the main jet.

1. Float height is the manual is 22mm. But this is just a guide. The tang on the floats when new are tangential to the pivot pin. However after mangling them several times, you may notice that they are no longer tangent. So feel free to adjust the float height to 23 or 24 mm. That little offset is magnified by the ratios of tang to pivot and float height to pivot. As long as your covering the jets it should be fine. Measurement of the amount of fuel in the bowl is a pain and not easily done unless you use a drain screw modified with a clear tube to view the fuel height.
2. If your having trouble with the overflows barfing out fuel, one thing for sure is the needle valve springs over time become unequally compressed and less resistant giving you all kinds of different measurements. I suggest buying new needle valve sets. You will notice the difference immediately when you set the carbs on the bench. The floats will touch the needle valves and not compress the springs at all. Also these stock Keihin carbs use a lot of o-rings which over time will not seal. Especially the o-ring on the needle valve seat. If this one is bad, your carbs will eventually overflow. These needle valves are brass on brass. Some are rubber on brass. So there is no substitute for a good spring in the needle valve.

I'd be looking to come too, that would be great 😃

Hubert

Good stuff, Hubert. 👍

If there are no objections the meet up will be on Sunday 30th June.
I'll be there from about 1100 onwards. Looking forward to meeting everyone who can make it.

I had a feeling this was on the cards. I sent an email a couple of weeks ago and didn't even get their automated replay.
I am down about £910 as I have been waiting 11 months for CB500 pipes. I did pay on credit, we'll see.
I did nearly jump an buy the delkevic set when it was £950, but now I'll have to pay £1100.

For me the question is formost: can I indeed compensate the needles clip in 4th groove by adjusting the air screws to two turns out, like that American Honda specifications booklet suggests or should i return to the European set up with needles clip in 3rd? I have always had my doubts about that US booklet and I therefore volonteered to experiment.

They are going to compensate in different ways, although overlapping in their effect, the two changes that is.

Lifting the needle iis going to give a response in fuelling curve in roughly a parabolic curve being nil or low change at closed throttle slide ... also nil at full open, with increase in fuel through that curve region.
Essentially raising the equalised air fuel ratio throughout the mid range of slide position by placing the needle higher in that air controlled slide movement.

The change in idle jet circuit will not shift the maximum flow without change to the jet number .... but will give less fuel at idle by opening the air inlet via the screw .... then reach maximum flow for that circuit (conditional on that jet number) further up in the vacuum range of venturi flow.
Longer "slope" response from idle circuit, meaning it doesn't ramp up /accumulate fuel increase in quite such an steep response as having the screw further inwards.
This may give you flat spot just off idle when lifting the throttle initially, it can also give problems at idle in consistency as it requires the slides to be set lower on "master" rpm screw, making it potentially out of range in vacuum specifications listed in carb balance.  Sometimes this affects throttle response in rolling the power on and off as the vacuum gets too high with closed throttle when closed with revs higher .... feels a little "sticky" and non linear with more severe engine braking affect on closed throttle.