Express II float screw question/brain teaser

It's a non-adjustable, tan-colored float, from 1980. Should the screw that holds the right side of the little pivot/axle/hinge thing in place be tightened all the way? If not, then what?

Here's why I ask: too tight and the float doesn't move so the bike won't run at all. Too loose and it runs but the float eventually vibrates itself disconnected and the needle drops into the bowl and then there's an environmental disaster under the bike.

I can't imagine such a basic element of any bike needing to be finessed this way, but I'll taken the carb on and off a dozen times to make incremental adjustments and there doesn't seem to be a sweet spot that's just right.

This is a new problem, by the way. When I got it it ran poorly but reliably. Then I thoroughly cleaned the carb and it ran beautifully when it ran, but became subject to stalling out after running WOT (or close) for any length of time. For a while I could get it started by pulling off the gas line for a moment and then winding it up and going again. Now that fix doesn't work anymore.

I installed a new float valve, but that doesn't seem to make any difference. All the lines into the carb are clean and open. Yes, the petcock is fine.

Any help is appreciated. All hail the patient and wise Express gurus who give their so generously of themselves to help knuckleheads like me stay on the road.

Re: Express II float screw question/brain teaser

Not the most glamorous question ever, I admit, but still...

Re: Express II float screw question/brain teaser

The short answer is that the float should be able to pivot with the screw all the way in holding the axle stationary.

As for the other problem, do you have the vent open on the gas tank? I had a situation where if the vent wasn't open all the way it would bog down and sometimes stall for a minute. After a short time enough fuel would slowly flow into the bowl and fix my problem.

I'm in the market for a new needle valve. Where did you get yours?

Re: Express II float screw question/brain teaser

Thank for your help, Jeff.

I found the needle on ebay for $5 and change, but it was the only one I saw when I looked last. I'll bet they're available most places that sell cycle parts tho, because the same needle fits a hundred different Hondas.

My gas cap has an "on" and "off" position (and neither locks the cap in place). Should one of those vent the tank?

The float doesn't pivot at all to speak of with the screw in all the way and the float needle in place. I'll look again tomorrow and see what's what. Right now I can't recall whether the float fits and moves without the needle in place. If that's the case, maybe the float or the needle are incorrect. But that doesn't account for why it ran as well as it did for as long as it did.

Honestly, the more I work on this bike, the more I like my FA50.

Re: Express II float screw question/brain teaser

Bent hinge?

Re: Express II float screw question/brain teaser

Answers...

Yes the screw should be tightened all the way down. If your float does not move whith the screw tightned you have another problem. Maybe the pivot rod has a burr or is coroded in some way as to not let the float pivot on it.

Check to be sure your gas tank cap is venting, should be in the "on" position when running the bike. Try taking off the fuel line and draining tank into a container with the cap switched to both on and off. in the on position fuel should run out of the tank at a good rate, in the off position fuel will run out a little bit but will slow and stop eventually as there is no air getting into the tank to replace the fuel that has run out. or air might try to flow back up the fuel line and "bubble" into the fuel tank.

Re: Express II float screw question/brain teaser

Ive tried a float,screw,and pin from one carb I have to a cple others I have and on some it works fine and others it doesn't allow the float to move.Also noticed some floats are clear/yellowish plastic and some black rubber or something so different yrs maybe little bit different parts.A lot of these aftermarket parts are made cheaply and they don't list them correctly or send whatever they have at the time you order

Re: Express II float screw question/brain teaser

As Shawn said, On for the vent.

You should turn the gas cap and petcock to off when you're done riding to keep gas from evaporating or even draining out of the carb overflow onto the floor.

It appears there are 2 different types for the Express, but I believe the more common (and one that I have) is

part # 16155-883-005

.

The whole point of the float is to be able to move, so if that's not happening there's a problem. Shawn had some good tips on that too. In this carb the plastic float needs to move freely on the metal post.

If you want to take pictures of how you put the needle/float together that may help. I also want to see if my needle is as bad as I think it is compared to your new one. I think the spring isn't coming back out far enough. I haven't found any for $5 from a reputable site but lots for $10 but closer to $15-$20 for a 5-pack!

Re: Express II float screw question/brain teaser

Just the opportunity to think and discuss this with knowledgeable people has been very helpful so far. Now that I've taken the pictures below, it's apparent there is something wrong with my setup.

Should the needle protrude this far above the body of the carb, as in the first picture?

Should the float be in the position in the second picture when the carb is empty?

Third picture is the way I've been running it, with predictable results.

So what's your diagnosis? Wrong float? Wrong needle?

carburetor and float photos (edited)

Re: Express II float screw question/brain teaser

If the float doesn't move up and down freely in this pic then something is wrong. As you know, when mounted the float would be tilted down. Gas should be able to fill the bowl and move the float up and close the needle valve.

The pic without the float looks fine. The tabs on the float should fit above and below the bit sticking out. Just yesterday I learned that the ideal position for the float when up should be just about parallel. That means that something looks wrong in this pic.

If the camera is good enough, can we get close-ups of how the needle & float are put together and a separate one of the metal post that holds the float in. As close as possible while still being in focus..

MopedArmy is a great resource. I don't get too many chances to share obscure carb maintenance tips, especially on a vehicle I know way too much about. :)

Re: Express II float screw question/brain teaser

Thanks for your input. Would you agree that either the float or the needle are not the right parts for this bike? Should the needle stick up out of the body of the carb like it does in the pic without the float? Or should it be flush? Because that seems to be what's fouling things up. Either the needle is too long or the tab on the float is too shallow to accommodate the needle. One of the parts has got to be wrong. Right?

Re: Express II float screw question/brain teaser

They both look right. Let's see if I can explain it a different way..

On this page the third pic has a float upside-down.

When properly assembled, the part of the needle sticking out should be in the slot. The spring should be able to contact the center tab in the middle.

The other way to say it is that if you aren't first hooking the needle into the float and lowering both together until the needle goes into the hole then you're probably not doing it right.

Re: Express II float screw question/brain teaser

Well now. I've been relying on gravity to let the needle drop as the bowl empties. There has never been a spring (or anything else) to connect the needle to the float on this bike.

So there should be four parts involved, right? The float, the hinge, the needle valve, and a spring to tie the float and needle together?

Re: Express II float screw question/brain teaser

You're right - gravity should bring the float down and the needle with it. Sorry for the confusion. The little dot at the end of the needle is spring-loaded which is what I was talking about.

The parts involved:

Float

hinge

needle valve

Screw (holding hinge in)

Once again: as long as the float moves up and down freely while the screw is fully tightened, you should be OK. If not, there's a problem with that movement.

Re: Express II float screw question/brain teaser

I'm embarrassed to admit this, but I've been trying to get the needle to simply rest against the top of that tab instead of inserting the needle flange into the slot for it on the float. A stupid newbie mistake -- and I'd be repeating it indefinitely if not for this forum.

This is what I get for thinking I know what I'm doing. I don't deserve my bike!

On the positive side, it now takes me less than 60 seconds to take the carburetor off.

Thank you, Jeff, for your patience. You've been great. I'm putting the carb back on and I'm going for a ride in the rain.

Re: Express II float screw question/brain teaser

I don't know about other bikes but it's so easy to work with the carb on the Express. Good thing, since they're so finicky.

I'm assuming this fixes your problems, especially when combined with the gas vent issue. Ride on!

Re: Express II float screw question/brain teaser

Andrew Kotcher /

so problem solved?

Re: Express II float screw question/brain teaser

Yes, thanks.

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