Popping anyone?

[Mike Cecchini]

Either way works just fine - as long as you are not depressing the pin.

Dave

That's the issue ...... with the carb upside down, it's really hard to tell if the pin is depressed. It might be depressed 1--2 mm and you'd never know it.

If you hold the carb as shown in the manual......and let the float tab lightly touch the pin, you can hold he carb at that position (on the right height bench) and easily see what is happening......as it happens.

Since you are "Dr. Carb" and probably done this 1000 times...... I do not question your word on this. I just like to see the float ever-so-lightly seat the valve and stop in slow motion so I can see exactly what is going on.

Having just gone through 12 carbs and checked all 24 floats to be absolutely positive all were dead-on 15.5 mm...... I was amazed at the variations.

Thanks for chiming in Dave.

[SPLINTER]

OK everyone, do I understand this correctly? The floats should just lightly touch the the pin (spring loaded plunger) so as to verify that the 15.5 mm is correct. I'm just a little baffled as to how this condition would cause a popping during idle. I will wait another day or so before I get to them again. If there are any other suggestion that make sense, I will do the work all at one time. Just trying to avoid another couple of engine tilts. Funny thing, I asked another old timer out of California if he thought that the floats not adjusted correctly would cause the condition described, his answer was "not likely". Odd? Nevertheless, I will sick to this forum as far as it takes me.
Should it compress the spring loaded plunger a little, or just have contact?

[Mike Cecchini]

<<The floats should just lightly touch the pin (spring loaded plunger)
<< so as to verify that the 15.5 mm is correct.

Yes......but you must verify that the float valve (that the spring loaded plunger is attached to) .....is closed at this moment of light touching.

<<I'm just a little baffled as to how this condition would
<<cause a popping during idle.
Well.....that's the same feeling I have. Something else is going on here, but first things first with carbs......and everything starts with float height, so make sure this is right so we can move on to other basic things.

>>Just trying to avoid another couple of engine tilts.
So the carbs are still on the motor ?? Hell......if the engine is already tilted, I'd be taking the carbs off and doing this on a bench.


>>Should it compress the spring loaded plunger a little, or just have contact?

No compression of the plunger spring is tolerable......just contact.....but with the valve must be closed......this is CRITICAL. This is why the book shows the carb off the bike and held in a near vertical position.......then tilted back 5--10 degrees to let the float assembly close the valve while only LIGHTLY touching the float tab to the spring loaded plunger.

With the carbs on the bike and in the (near) horizontal position.....just touching the tab to the float valve spring loaded plunger doesn't mean the valve is closed. Do you understand this specific point ?

[SPLINTER]

I Mike! I see what you mean. Will go ahead and check & adjust these as needed when I remove the carbs for one last time!
Mike, wouldn't it make more sense to have the carbs upside down and perform this adjustment? When upside down, you know that the valve has seated under its own weight, therefore, the float tab would only need to touch the spring loaded plunger when the 15.5 mm dimension is achieved.

[NobleHops]

Contributing nothing, I'll just chime in that I am constantly in awe of the collective experience and wisdom as well as the willingness to share it.

Carry on!

[EMS]

wouldn't it make more sense to have the carbs upside down and perform this adjustment? When upside down, you know that the valve has seated under its own weight, therefore, the float tab would only need to touch the spring loaded plunger when the 15.5 mm dimension is achieved.

daves79x » Tue Apr 05, 2011 9:11 pm

Either way works just fine - as long as you are not depressing the pin.

Dave

It's like with a lot of other things. There are different ways to achieve the right result. Chose the one that works for you and you are comfortable with. I have used the upside-down method with good results.

[daves79x]

With your carbs off, observe where the idle circuit sucks fuel from. You will see that it requires a pretty high fuel level to be immersed in fuel - much higher than the main jet tower. With a low float, fuel just sloshes into the idle circuit as opposed to the jet tower being immersed. This results in the idle circuit alternately supplying/starving the engine. The main jet circuit is not so much affected as it sits much lower in the bowl.

In any case, a low float level has absolutely been verified to cause this low-speed 'miss'. There are obviously many other possible causes, but this is indeed one of them.

Dave

[SPLINTER]

Any other suggestions as what to check or look for when taking off the carbs?...to address this issue of popping?
Dave what you say makes sense. Thanks for the explanation.

[Mike Cecchini]

I Mike! I see what you mean. Will go ahead and check & adjust these as needed when I remove the carbs for one last time!
Mike, wouldn't it make more sense to have the carbs upside down and perform this adjustment? When upside down, you know that the valve has seated under its own weight, therefore, the float tab would only need to touch the spring loaded plunger when the 15.5 mm dimension is achieved.

Sorry to put you through a carb removal Splinter......but us guys that do this once every blue moon have to do some things the old fashion way, the way the book says so....to guarantee the results are 100% right........according to the book.

If you invert the carbs I found that the weight of the floats pressing straight down can compress the spring loaded plunger 1--3 mm's and the 15.5 mm setting will be off by this amount. B-I-G mistake.....and the bike won't run right......and you'll be chasing your tail for God only knows how long before you finall set the floats correctly.

Again....... if you did this day-in and day-out.....you'd get the "feel" of all this and could do it the way many of the experienced carb builders can (upside down, sideways and many other positions) ..... but you're not experienced......and neither was I ......so I did all 12 of my carbs just like the book says.

Let's face it Splinter...... you really only want to do this one final time because it's such a pain in the ass to take X carbs on and off........ this is one BIG reason I hate airboxes and have removed mine from my 80 rider. My other 80X is 100% stock......so I wanted to be DAMN sure the carbs were right because I'm only tilting this motor ONCE.

My best.

[SPLINTER]

I see your point Mike. I will take that into consideration.

[SPLINTER]

OK. Tonight I take them off to check/adjust the floats. Any other recommendations to check something would be welcome. I don't want to do this yet another time. Did I mention that I had set the air/gas adjustment screws 3 1/2 turns out according to an old timer Honda mechanic I spoke with locally. Worked for Honda since 1978. I did notice a tinge of a gas leak at one of the bottom bowls. Any recommendations as to what gasket sealant I should use?

[EMS]

Did I mention that I had set the air/gas adjustment screws 3 1/2 turns out according to an old timer Honda mechanic I spoke with locally.

Maybe a little much. They usually recommend 2¼ - 2½ turns.

[spencer]

Any recommendations as to what gasket sealant I should use?

If you are talking about the bowl gasket, you should not need any "sealant." If they leak, you need new gaskets.

[daves79x]

If you did not separate the carbs and replace the o-rings, I'd check pretty closely to be sure your leak is not from one of those connecting joints. It's a crap shoot to not replace the o-rings and expect no leaks. The fuel inlet joints are the most prone to leaking. Anyway, as Spencer said, replace the bowl gasket if that is really where the leak is - use no sealant there. Again, before they go back on, wet test them on the bench for at least 24 hours.

Dave

[SPLINTER]

Well...this is how far I got: Took the carbs off again (#4) and found that the float valve pins were reacting differently one from another. What I mean by that is that with the carbs upside down, and all the floats exposed, the first two I checked had a nice springy action when depressing the floats. The third and sixth had virtually no spring action at all. I'd press down on the float and it would stay down. CRAP! I'm ordering a new set today and will replace them all. The gaskets I used were new from Randakks and have been compressed now three different times. Could it be that they already flattened out? Is the recommendation to replace them again?