Topic: Air screw to reduce decel popping?

[PeWe]

I initially thought about this hole. All small holes have a purpose.

[PeWe]

I wouldn’t go digging around in those itty bitty holes with any thing harder than the jets, nozzles, offices themselves are, if I were you..

Especially if your dad hasn’t in the past.. Virgin Honda brass is hard to come by…

Copper and bronze wires can be purchased in thousands sizes like 0.020 for a few bucks at model train suppliers..

Copper is what I prefer because it’s several times softer than brass and bronze..And Bronze is harder than Brass which is what you got unless you have them removed before digging. But look at Delta’s cutaway of a pilot jet in case yours are partially plugged or varnished up to the next smaller size..

Check your timing too.  I like somewhat  advanced initial timing and limited centrifugal max timing. Remember your ignition fires on the exhaust stroke too, so don’t blame it all on your exhaust lighting it off on the deceleration..

Advanced initial timing is a no-no with low octane fuel, but makes for a torquey just above idle launch at the stop sign with premium fuel when trying to tame the open exhaust from the local germaine..

Have you tried premium to see how it affects your deceleration popping..?

Believe it or not, I’ve been running premium since the day I put it all back together. But am now realizing the compression on these engines will never need it. I had a thought that the lower octane may actually make it run a bit better

I can not use the lower octane here. E10 fuel with most likely more water.

I tested when it still was only E5 on my K6 when it had lower compression than today. It ran leaner.

My K2 had 150-160PSI with fresh stock size pistons.
Same tester showed 170-175PSI with CI +0.50mm K7 pistons.
So Shell V-Power to that bike too. Like my car and K6.
It had the severe throttle off popping with Shell Power and 086A carbs that must be dirty inside.

I'll focus on popping sound coming season.  It had a little of it.
 If fuel additive will help. Stronger dose. If not, air channel to clean.
Last season was jetting of the  064A carbs and tuning of the charge regulator.
Add a voltmeter you can look at when riding will make you to adjust to >14V when fully charged around 4000rpm or before.
Not >14.5V that easily will become >15V. I have adjusted some on both my bikes and 3 regulators.

[Bigmant]

UPDATE! And interesting knowledge.

So I’ve taken the carbs off. And discovered some interesting things. You can see in the picture below, the Honda made rubber insulator is a different type of rubber than the cheaper version from 4into1. Important to note, 4into1 sells both. I just happen to get mine from south bend Honda.

They both are equally malleable, there are no cracks on the cheaper ones, but Honda’s are numbered for the cylinde and there is a different sheen of rubber. If you’ve ever watched racing, you’ve seen how fresh tires always look more shiney? That’s how the cheaper ones look. So perhaps that makes the genuine Honda seal better? We’ll see.

Next, the 4into1 replica insulator clamps aren’t adequate. I can pull the insulators off when they are as tight as possible. Unlike a normal circle clamp, you can only get either genuine Honda or replica’s so tight before they bottom out. So I’ve ordered some normal circle clamps from Carpy’s that fit the insulator ring. That should help seal them up better.

I also took this opportunity to clean all the holes with a small gauge carburetor tool I bought on amazon. All the holes were clean, which was not surprising, but rules it out. I also found most of the floats were out of spec, and were filling up the float bowls too much, which as I understand it can cause a too rich condition. So now in spec at 26mm should help as well.

Lastly! Some interesting air screw findings for those that don’t know this. First picture is at fully seated minus 1/8th. You can see that the hole of the aircrew is perfectly aligned with the air intake hole on the air filter side. The pictures after that are 1 turn less every picture. Passed 3 turns, the hole isn’t visible any more. I didn’t know that’s how the screw worked, so it was interesting to see.

More to follow as I get new clamps and take it for a test drive. We’ll see if this fixes the popping and what I think was ultimately the bike running too rich.

[Don R]

 The worm screw clamps can bite into the rubber and cause it to bunch up as it tightens, I have some thin aluminum flashing (or pop cans) material that I use scissors to cut shims from to slip under the clamps. I got some aircraft type clamps that also have a built-in shim behind the worm gear slots for my turbo connections.

[Bigmant]

I’m also going to post this here because it makes SO much sense. I was never a believer of how important the float adjustment was, because I figured it was a glorified toilet bowl stop. But not the case! Enjoy:

Think of it like this, when you put a straw into a glass of liquid the liquid tends to rise up the straw because the other end is open to the atmosphere. The hight that it rises to is due to atmospheric pressure acting upon the surface of the liquid and the specific gravity, so to speak, of the liquid itself. The same goes for the needle jet in your carb. To some degree, i have no idea how far, the fuel will rise inside of the tube. This effectivly decreases the distance the fuel has to travel to enter the carb throat. With this in mind, if the distance the fuel has to travel to enter the venturi is less, more fuel can enter the combustion chamber for a given amount of vacuum. Just the opposite is true for a lower volumn of liquid in the float bowl.

[scottly]

Off topic posts will be/have been deleted from this thread.

[Deltarider]

[...]
Lastly! Some interesting air screw findings for those that don’t know this. First picture is at fully seated minus 1/8th. You can see that the hole of the aircrew is perfectly aligned with the air intake hole on the air filter side. The pictures after that are 1 turn less every picture. Passed 3 turns, the hole isn’t visible any more. I didn’t know that’s how the screw worked, so it was interesting to see.
[...]

The position of that (crossdriled) hole in the airscrew in relation to the inlet hole in the mouth of the carb is irrelevant. Mixture is only defined by how far out or in the airscrew is.

[newday777]

I initially thought about this hole. All small holes have a purpose.

Per
I just had to derack the right 2 carbs off a set of K2 carbs that I thought I had cleaned fully because I couldn't get the clear tube test levels to change blowing into the right atmosphere breather tube like the left side did on the test rack. The #3 carb I had to pull out the 90° elbow to fully clear the old dried MBTE white dust buildup. What a pain this set has been because of it.
A set of used steel guitar strings is a must have tool for cleaning it out of the various ports. The emulsion air feed tubes and the bowl drain holes as well as the main and slow jets were plugged solid with the old white dust that 3- half hour runs through the ultrasonic cleaning didn't touch.
Hondaman really explained it well in his book. A great resource if anyone is working on these carbs that had gas left in them for years to dry out being exposed to high ambient moisture. The bike sat in an unheated, un air conditioned museum with less than 10,000 miles on it, last run in 2014. American ethanol gas of the 90s and 2000s really did a lot of damage. See the before pictures of the carbs to know what to look for and expect it to take a lot of deep cleaning that spray cleaning/ultrasonic cleaning just won't be sufficient to get them clean.
The tank has pin holes too, also from the moisture that was on the top seam down from the filler cap, that I found while derusting the tank last year.....
I even found a cracked bowl overflow tube yesterday and had to solder it to fix it. No more leaks now on the test rack. All the bowls and brass is polished up too.
Today I hope to get them run on one of my bikes and do a vacuum sync on them before sending them on to my friend.

[PeWe]

Fishing line might work too in that air jet? A little bit softer, not scratching.
Followed by chemicals and compressed air.


A good reminder before mounting the carbs on bike.
And when stock airbox and bowls are off.

The upper vents another holes that can clog.
If fuel in both bowls will bubble and overflow when blowing in the vent hose, it must be good.  2 hoses, 1-2 and 3-4.

[Bigmant]

Fishing line might work too in that air jet? A little bit softer, not scratching.
Followed by chemicals and compressed air.


A good reminder before mounting the carbs on bike.
And when stock airbox and bowls are off.

The upper vents another holes that can clog.
If fuel in both bowls will bubble and overflow when blowing in the vent hose, it must be good.  2 hoses, 1-2 and 3-4.

For everyone’s awareness, here’s the small hole carb cleaning tool I bought. $5.99 on amazon and it works great. It fits in all these vents we’re talking about.

https://www.amazon.com/gp/aw/d/B09TW6L7J8?psc=1&ref=ppx_pop_mob_b_asin_title