My Resurrection Thread

[Designer]

So you haven't replaced the float valves and o rings? That's your problem. Do the check I mentioned earlier with the hose.

As for the float needle, it's in perfect shape. brand new with the carb rebuild. I included it in a picture above.

[hillsy v2]

Confusing. He doesn't talk about the seats - just the needle....and says he doesn't know what the seats go into....which tells me he probably hasn't taken them out and changed the orings.

It's not rocket science - there's only a couple of ways the carb will overflow - bad float needle, float needle seat oring leaking, stuck / sinking float or incorrect float height.

[Herb]

The float setting should be just at the point that the float starts to compress the spring on the needle valve. If it is being allowed to rest on the needle valve it is too high.

Back in the old days the float valve needles were solidand the float could rest on the needle when setting the float height. Can't do that any more.

Also check to see if there is any dirt on the seat.

[Designer]

Yes, It is a bit confusing.
Dave said this

so, not seeing any reason for these carbs not to be good, I installed the rear and gave it another try. I'm actually getting fuel overflow from BOTH of the carbs. is there something more I could take apart? the float needles look brand new. what do they seat into? any chance there might be an o-ring or something missing? Just can't imagine that both of them would be bad.

[ncdave]

so, not seeing any reason for these carbs not to be good, I installed the rear and gave it another try. I'm actually getting fuel overflow from BOTH of the carbs. is there something more I could take apart? the float needles look brand new. what do they seat into? any chance there might be an o-ring or something missing? Just can't imagine that both of them would be bad.

So you haven't replaced the float valves and o rings? That's your problem. Do the check I mentioned earlier with the hose.

the carbs were sent off and completely rebuilt. That included replacing the rear carb because it was stuck solid and could not be brought back to life. I'm going to try adjusting the tab for the needle to see if it's just not seating completely.

[ncdave]

Yes, It is a bit confusing.
Dave said this

so, not seeing any reason for these carbs not to be good, I installed the rear and gave it another try. I'm actually getting fuel overflow from BOTH of the carbs. is there something more I could take apart? the float needles look brand new. what do they seat into? any chance there might be an o-ring or something missing? Just can't imagine that both of them would be bad.

I don't know carbs, so just taking wild guesses as what the problem could be. I've been messaging with the guy who rebuilt them. He suggested trying to adjust the float needle tabs. I'm going to move them UP to try to put a bit more pressure on the needle and see if that works. if not, I'm going to pull them and send them back to him for further diagnosis. I was just hoping I could figure it out myself.

On the positive side, both cylinders are running. Once these carb problems are out of the way it should be good for some neighborhood test rides.

[hillsy v2]

the carbs were sent off and completely rebuilt.

Oh dear - that's a bit of a worry.

You can check this yourself though:

While you have the carb out - fix a piece of hose to the fuel inlet and blow into it. With the float and valve removed - put your finger over the valve seat. The oring for the float valve might be leaking - this will test it. If that's good then put the float and valve back in and blow again. With the carb upside down the air flow should stop.

[ncdave]

While you have the carb out - fix a piece of hose to the fuel inlet and blow into it. With the float and valve removed - put your finger over the valve seat. The oring for the float valve might be leaking - this will test it. If that's good then put the float and valve back in and blow again. With the carb upside down the air flow should stop.

valve seat being the tube which the needle fits down into???

[hillsy v2]

While you have the carb out - fix a piece of hose to the fuel inlet and blow into it. With the float and valve removed - put your finger over the valve seat. The oring for the float valve might be leaking - this will test it. If that's good then put the float and valve back in and blow again. With the carb upside down the air flow should stop.

valve seat being the tube which the needle fits down into???

Yes.

[ncdave]

ok guys...need some further guidance.

I pulled the rear carb and drained fuel. I connected a hose to the fuel inlet and plugged the output to the front carb and also plugged the overflow tube. with the carb upside down I blew into the hose. there was some backpressure, but a small amount of air was going through. I then turned the carb right-side-up. pretty much the same pressure was needed to allow that same small amount of air to go through.

what's this telling me? needle not seating?

[Herb]

When the carb is upside down with the float holding the needle down into the seat it should be relly hard to blow thorugh into the carb bowl. Either the needle isn't seating properly or the o-ring on the bottom of the seat itself isn't sealing.

This is a link to the carb diagram.

https://www.suzukipartshouse.com/oempar ... retor-rear


Part 24 on the diagram is the needle and seat. If you look closely at the seat assembly you will see a dark ring just below the threads, that is the sealing o-ring for the seat. The seat should be snug into the carb body.

[navigator]

ok guys...need some further guidance.

I pulled the rear carb and drained fuel. I connected a hose to the fuel inlet and plugged the output to the front carb and also plugged the overflow tube. with the carb upside down I blew into the hose. there was some backpressure, but a small amount of air was going through. I then turned the carb right-side-up. pretty much the same pressure was needed to allow that same small amount of air to go through.

what's this telling me? needle not seating?

Don't plug the overflow.
Try blowing right-side-up with the overflow open, air should flow.
Upside-down it should not flow air.

[ncdave]

thanks. will give that a try.

[hillsy v2]

If you haven't removed / replaced the float valve seat this is the o-ring that will be leaking.

[ncdave]

If you haven't removed / replaced the float valve seat this is the o-ring that will be leaking.

How likely would it be that both carbs have this same problem? very useful!!!

BTW...I tried the pressure test without covering the overflow. when upside down it was holding more pressure, but not completely stopping air (fuel) flow.

How does the valve assembly (24 in diagram) come out?

[navigator]

If you haven't removed / replaced the float valve seat this is the o-ring that will be leaking.

How likely would it be that both carbs have this same problem? very useful!!!

BTW...I tried the pressure test without covering the overflow. when upside down it was holding more pressure, but not completely stopping air (fuel) flow.

How does the valve assembly (24 in diagram) come out?

For 24 removal, there is either an inner hex, an outer hex, or a screwdriver slot.
Both carbs can have a bad o ring in that position from being baked clean without removal.
If you haven't replaced both parts of 24, do so.

[hillsy v2]

If you haven't removed / replaced the float valve seat this is the o-ring that will be leaking.

How likely would it be that both carbs have this same problem? very useful!!!

BTW...I tried the pressure test without covering the overflow. when upside down it was holding more pressure, but not completely stopping air (fuel) flow.

How does the valve assembly (24 in diagram) come out?

There is a small offset screw (#18) beside the float valve seat which holds the seat in place. This is not a VS carb, but it should still look like this:



Undo the screw and the seat will "pull" out. It may be stubborn but if you are replacing the whole thing you don't have to worry about damaging the old one (IE: grab it with pliers and wiggle it out). Otherwise you can use a plasterboard plastic wall plug and screw to wedge in the seat to help you wiggle it out.

[ncdave]

thank you guys!!!

[ncdave]

my carb rebuild guy says he replaced those o-rings as part of the rebuild. I'm going to proceed with pulling the carbs and sending them back to him for review.

Given my prowess with carbs, that will definitely be the best approach.

[Designer]

my carb rebuild guy says he replaced those o-rings as part of the rebuild.

That was pretty much my thoughts here. The likelihood that he didn't replace them was VERY small, if at all. Hence my not commenting on the o-rings/lack of being the source of your angst.

.....I'm going to proceed with pulling the carbs and sending them back to him for review.
Given my prowess with carbs, that will definitely be the best approach.

After all the disassembly & many tests you have done so far, I am quite curious as to what your Carb rebuilder will find that causes your overflowing.