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Needle Valves and float heights...

chuckycheese

chuckycheese

Forum Sage
Past Site Supporter
Charter Member
I'm rebuilding all kinds of stuff on the GS1100 and have a question about float heights. The book says to measure it as the tang touches the little 'springy' needle. If I do that, it is set up correctly but if I invert the carbs in the normal measuring mode (upside down), the float pushes it down a couple of mm... just from the weight of the float. Maybe it's an after-market float valve (the jets are Mikuni, for sure) and is a crummy valve. What do you guys think? Has anybody else ever noticed that?

I've rebuilt GS750 carbs about 5 times (I have 2 sets) and think the spring is strong enough so that it doesn't push it in at all when it's just resting on it.

I'm a little reluctant to order new ones because (a) they're expensive and (b) the bike ran really well when I took them off (I took them off because my intake boots were trashed).
 
my opinion: Your Boots were thrashed, likely leaking, the rich nature of the bowls thanks to the crummy float valves counter acted it a bit. I would chance to guess that when you put new boots on, with those valves, youre going to be a bit rich. Not necessarily bad, depending. But, if they are real bad, They'll let fuel in sitting, when that happens, chances are, as i found out, it will find its way into your crank case. If you have clear fuel line, and notice that the fuel in the line dissapeers after a while, could be an indicator of just this. Take a wiff of your oil, smell any gas? Were it me, for piece of mind, id replace them. But again, only my opinion.
 
Yah it may not exactly be sound, but I am not necessarily of sound mind either :P 8-[
 
TheCafeKid said:
Yah it may not exactly be sound, but I am not necessarily of sound mind either :P 8-[
Click to expand...

Me, too! Sometimes, I feel like I know a lot about these 'beasts' and then something simple will make me realize that I really don't.:-s

I took a look at my spare Gs750 rack and I'm sure the needle valves on the GS1100 are after-market.
 
Have to admit, I’m not sure how important the needle spring tension is. When checking float height the carb is up side down thus the weight of the float is resting on the needle – something that will not occur in use. I’m inclined to think that as long as the spring has reasonable tension, and returns the pin to full height, the system should work as designed even if the needle spring is a little weak.

The spring needles in my 550 carbs are not able to support the weight of the float yet the bike runs great. I do get a pretty strong gas smell from the bike though after it’s parked in the garage – no gas in the oil as near as I can tell.

As a side note, Z1 sells aftermarket float needles for a couple of dollar each. Might be worth it to upgrade.
 
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I have encountered crappy shoddy evil hateful float needles with weak springs. They are a sneaky abomination that will make you say bad words.

Replace yours pronto with OEM. These springs MUST be strong enough to support the weight of the float without compressing at all when the carbs are upside-down.

I don't know of any aftermarket sources that are trustworthy, unfortunately.
 
bwringer said:
These springs MUST be strong enough to support the weight of the float without compressing at all when the carbs are upside-down.
Click to expand...

Why?

Floats have always been adjusted with the carburetor hanging at the angle that just touches the spring loaded pin with the float tang, not far enough to compress the spring. There is no need to turn the carb upside down. The strength of the spring has little to do with it, all it has to do is hold up the weight of the needle, and apply a tiny amount of pressure on the seat.

If four different needles had four different spring tensions it might take a little more work to get the fuel levels correct.

You are going to check the fuel level in the bowl after it is together and running anyway, aren't you?
This is what really matters in the end.
 
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What?

What?

tkent02 said:
Why?

Floats have always been adjusted with the carburetor hanging at the angle that just touches the spring loaded pin with the float tang, not far enough to compress the spring. There is no need to turn the carb upside down. The strength of the spring has little to do with it, all it has to do is hold up the weight of the needle, and apply a tiny amount of pressure on the seat.

If four different needles had four different spring tensions it might take a little more work to get the fuel levels correct. Claro!!

You are going to check the fuel level in the bowl after it is together and running anyway, aren't you?
This is what really matters in the end.
Click to expand...

 How would you do that??

Using the conventional methods used by both the Clymer manual and the OEM Suzuki manual, inverting the carbs is the ONLY way you measure it....so, maybe, I'm confused by what you mean....(always possible!)
 
Bad words...

Bad words...

bwringer said:
I have encountered crappy shoddy evil hateful float needles with weak springs. They are a sneaky abomination that will make you say bad words.

Replace yours pronto with OEM. These springs MUST be strong enough to support the weight of the float without compressing at all when the carbs are upside-down.

I don't know of any aftermarket sources that are trustworthy, unfortunately.
Click to expand...

As always, Brian, I'm afraid you're right. I'm going to put in the OEM needle valves and will order them in the morning. By the way, the bad words have already been spoken!!8-[
 
chuckycheese said:
[/B] How would you do that??

Using the conventional methods used by both the Clymer manual and the OEM Suzuki manual, inverting the carbs is the ONLY way you measure it....so, maybe, I'm confused by what you mean....(always possible!)
Click to expand...

Factory manual provides a check to verify fuel level in the carbs, not just measure the float height.
 
chuckycheese said:
[/B] How would you do that??

Using the conventional methods used by both the Clymer manual and the OEM Suzuki manual, inverting the carbs is the ONLY way you measure it....so, maybe, I'm confused by what you mean....(always possible!)
Click to expand...

Any carburetors, instead of just plopping the carb on the bench upside down, hold it with the float hanging from the pivot, then just rotate it in your hand until the float just touches the needle, not compressing the spring at all. Once you have established the angle, set it on the bench at this same angle and measure the floats.
Was taught this technique as the correct way to do any carburetors by my dad about forty years ago, it has always worked for me.
Weak springs are of no consequence, as long as they move freely and have some tension.
 
Bad words...

Bad words...

bwringer said:
I have encountered crappy shoddy evil hateful float needles with weak springs. They are a sneaky abomination that will make you say bad words.

Replace yours pronto with OEM. These springs MUST be strong enough to support the weight of the float without compressing at all when the carbs are upside-down.

I don't know of any aftermarket sources that are trustworthy, unfortunately.
Click to expand...

As always, Brian, I'm afraid you're right. I'm going to put in the OEM needle valves and will order them in the morning. By the way, the bad words have already been spoken!!8-[
 
I need to look!!

I need to look!!

Nessism said:
Factory manual provides a check to verify fuel level in the carbs, not just measure the float height.
Click to expand...

I've got the Suzuki manuals for both bikes so....I need to find it!!8-[ (By the way, where is it??)

Also, how would I verify the fuel level in the carbs if I'm holding them in my hands???:confused:
 
Great!?!

Great!?!

tkent02 said:
Any carburetors, instead of just plopping the carb on the bench upside down, hold it with the float hanging from the pivot, then just rotate it in your hand until the float just touches the needle, not compressing the spring at all. Once you have established the angle, set it on the bench at this same angle and measure the floats.
Was taught this technique as the correct way to do any carburetors by my dad about forty years ago, it has always worked for me.
Weak springs are of no consequence, as long as they move freely and have some tension.
Click to expand...

Well, the Japsters should have put that advice in their manual. If they did, it might alleviate my confusion.:-D
 
chuckycheese said:
Also, how would I verify the fuel level in the carbs if I'm holding them in my hands???:confused:
Click to expand...

You can't. You set the float level.
You put the carbs together.
You start the engine.
You check the fuel level.
It's all in the Suzuki manual.
Read it.
 
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