Suzuki 2 Strokes

Hi!

Yes, but it is given a tolerance of +/- 1mm, so it should not matter whether measured with or without (0.5mm-)gasket .
The setting should be identical for all three carburetors.

I recently controlled the real fuel level at a GT380 using transparent hoses, mounted in place of the float bowl drain plug.
The setting by Suzukis method was the same for all three, and OK.
But: the real fuel levels differed by 6 mm between the carburetors. One was OK, one tended to overflow sometimes, one was much to low.
This is due to slightly different weights of floats and slightly different (or worn) float needle valves.
Maybe too, once a float was resoldered, therefore a bit heavier.

The fuel level should be approximately in the height of heads of the float bowl screws.


bye
Markus

+1 to Markus on everything he wrote.

Another +1 on that tip.

That looks like a really useful tip for checking float levels on something like a GS-series 4 cylinder, which can be a real PIA to get the carbs off & back on.

...GS-series 4 cylinder, which can be a real PIA to get the carbs off & back on.

I can tell you exactly what it is at the 3-carbs-rack.
But you wouldn't want to hear it.

I get it. I get it. My world has always been upside down.. The external tube method only holds true if everything is perfectly level. Tipping even slightly in ANY direction = all bets are off. So where are we really? Most carbs don't even mount level to begin with. I think they call this bench racing

thanks for all the info, I do like the clear tube method, pretty nifty , I totally forgot about that, I used to know people that did that years ago, but the last carbs I messed with are from my superhawk, very easy to adjust, just take the bowl off with the gas shut off and look but the gt750 carbs are way more complicated. The left over flow tube on mine drips more than the other two so there must be something going on in there, or this is an accumulation of dripping over the past two years that I just noticed , the bike ran good except for the excessive smoke from the left pipe,, the last time I rebuilt the carbs I did not replace the fuel line that connects them it was on there when I bought the bike, then I started thinking that if its cheap fuel line it might be degrading from todays fuels (I have seen this happen 1st hand) and it might be clogging stuff up in that carb,, guess ill take it apart in a couple of weeks and ill update you guys. I rebuilt a 351 Cleveland about 12 years ago and I bought "good" fuel line from autozone, and in about 2 months the car started running weird, after checking everything I finally took the carb off and there was black pieces of fuel line in it! I checked the fuel line and it had just started breaking down, I ended buying earls blue fuel line and never had a problem again. That's when I started learning about todays fuels, pissed me off,,,,,since then I have been working on a 454 chevy and just make sure I buy good fuel line ,, Coyote I actually found that same book you mentioned , I have that and a Clymer book and both tell you different , and to be honest I cant remember now which way I measured I will make sure to measure it with and without the gasket to see which way I had it set,,i appreciate everybodys help very much thanks guys!!!!!! by the way how do I post pics? It doesn't let me , and I forgot what was said last time, damn im forgetting a lot lately .....and to clarify so with gasket fuel is lower or higher? seems the gasket would make the bowl farther away from the carb body so would that mean more fuel? but then if you measure the float and carb body the way the books say it seems like without the gasket that would put the float closing later , letting more fuel in, and with the gasket it would close earlier? I worked a long shift and cant seem to concentrate right now, think ill go to bed ..

markush wrote:I recently controlled the real fuel level at a GT380 using transparent hoses, mounted in place of the float bowl drain plug.

can you tell us what those parts are part# or where you get that wonderful stuff to check the fuel level externally

can you tell us what those parts are

The thread of the drain plugs is M6x0,75.
You have to find hose fittings with this thread in your country.

I got mine from a Net-shop in germany which sells steam model engineering accessories.
http://www.dampfmodellbau-keifler.de
go to "Verbinder" in the left menu.
part No.: 14-2025/2
hose No.: 14-2036/3

I forgot to mention. Although it is self-evident: In the method shown, the carburetors must be in the normal installation position respectively have the appropriate inclination.

ok, I looked at the video that you can get for the carbs, found it on youtube, it says if your using mikuni needle and seat the measurement is 27.60 mm which is 1.08 inches, and if you use a after market needle valve for the float the measurement is 26.00mm or 1.02 inches,,, so stock is 1.08 and after market is 1.02 for the measurement so correct me if im wrong but this is less than the width of a finger nail !? right ,, this is absolutely nothing unless im measuring wrong or my vernier caliper is off or its been that long since I have measured with it, I seriously might be reading it wrong but that looks like nothing at all ? am I wrong???? I used an aftermarket kit not mikuni so I set the floats at the 1.08 and not the 1.02 would this make that much of a difference ? I have not taken the carbs off yet but I know I set them to the stock setting....just wondering if you guys go by what the video says or just go by the stock setting no matter what kit you use? and also the video says to use the gasket?? just throwing that I there .....

I didn't watch the video, but I never heard such nonsense. How do they know what aftermarket needle I have? How do they know how thick my washer is under the seat?. That difference they're talking about is just barely more that what Suzuki gives you for a tolerance (+- 1mm). The thing nobody seems to hit on is the needle springs. Could be stiff, could mushy. Personally I think those springs are the biggest variable. Could make a difference of the entire length of the little plunger. Also I think that is why perfectly set floats on the bench turn out to be way off when put to use.
How do you compensate? Which way do you compensate?. The ONLY way you can really tell where you're at is by the external riser tube. But nobody seems to have the needed fittingg, not to mention it's gonna be messy. Also it would require repeated removal of the carbs which is not so easy on some models. Take for instance 74-77 GT380 and GT550. Just to change the needle clip position is an all morning job. If you go the wrong way, you get to do it all over again. And each time you have to re-sync the carbs all over again. I'm getting off track here. Bye

I agree coyote, wish I could post the video, you can find it on youtube under gt750 carb float adjustment I believe is what I put,, and I did notice that the needle spring was way stiffer than the one I took out, what a pain in the as@#$, im not sure how im going to go about this or if I just leave it alone , I will decide when my throttle cables get here, im just trying to get an idea of what to do before I start doing it....

I would say it wouldnt matter if its a Suzuki or after market float valves the floats need to be set so the valve closes with the floats at the correct level . Too high or low fuel level also affects how the engine runs so getting it right is more important than just fuel leaking out . This info is for hi reving 4 strokes but it gives ya the idea http://www.factorypro.com/tech/tech_tun ... gines.html" onclick="window.open(this.href);return false;

You need to read between the lines here. Float level is measured from the gasket surface really means the surface the gasket mounts to, NOT on top of the gasket. Is it me or what he says about varying the float height to accomplish leaner or richer normally done by changing needle clip position? If you lower the needle (raise the clip) goes leaner and raise the needle (lower the clip) to fatten it up some. It's all to complicated. What's the purpose of the needles having springs? Maybe it's to dampen the reactions from the fuel sloshing around in the bowl. I don't know. I do know that needles with stiff springs will shut the fuel off sooner and a lower level than needles with mushy soft springs. Is my logic off?

My Brain Hurts!

well the throttle cables I ordered or not available anymore from bike bandit, they have one but not the other so its going to be a while before I tear stuff apart, im with you! my brain has been hurting ever since I started reading all the different ways that different books say to do this, and all have a different measurement ,, I found a third book that I have and its different than the 1st two! I might look into doing the tube thing or just leaving them alone it runs good just don't want one side to be to lean because of fuel level so I will probably do something damn it