Suzuki GS125 Carb questions

[MikeT]

Hi all,

Hoping for a little advice. I recently bought a Suzuki GS125 ESX (1999). It has had significant work done on it in the past (Engine replaced!). It's having some trouble, engine sounds nice but drops and splutters at mid revs / mid throttle when trying to accelerate. Also none too happy when cold. Engine also seems to be getting hotter than I'd expect after a while.

So, having replaced the plug, air filter, cleaned the fuel tap, I've moved onto the carb, and this is where it gets interesting.

This year of bike should have a CV carb, but this bike has a slide carb. This may match the engine (how do I check what the engine should have?).

Inside the slide carb I've discovered the jet needle is the one for the CV carb ("4DZ35"), instead of the slide carb! However the Main Jet is the right one for the slide carb ("95"). I haven't yet worked out what all the other jets are, if they're even labelled.

Float level setting was closer to the CV carb setting (5mm off the slide carb setting).

The jet needle position was set as it should be for the CV carb, should I move it one notch to set it as it should be for the slide carb (as if it was the right needle for the slide carb!)

So, questions! (any advice and opinions greatly appreciated!)
Does this sound like a total bodge, or is this likely to have been an acceptable swap?
What else should I check for? (I'll try and measure the other jet sizes etc)
Should I just buy a new carb so I'm sure it's all good (are aftermarket copies acceptable?)
If I were to buy a new carb, how do I work out if I should buy a slide carb, or a CV carb? (bearing in mind I don't know what this exact engine would have had, can I check? Does it matter?)

As you might be able to guess, I'm not expert on carbs, but am happy to fiddle and work stuff out. I hope someone can give me some advice to help me on my way.

Thanks! (sorry for the length of post).
____________________
-------my small bike collection:-
Suzuki GS125 ES (X?) 1999; Suzuki GP125 1984 (may soon be for sale, runs nicely for its age); Honda C90 1995

[The Artist]

All settings on the carb should be for a slide carb because it is one. Don't set anything to CV carb specs because they will be wrong.

I recently upgraded my gs125 engine from 1995 model to a 2007 en125 engine and effectively bodged the same old carb on it. Makes no difference really as the engines don't change much.

When cold it barely pulls and will cut out if I rev it quickly. Once warm it is fine though as it should be.

[MikeT]

Thanks for the amazingly fast reply.

[The Artist]

Needle should have a small circlip on the middle notch as standard I think.

TBH, sounds like it has been put together out of a box of spares. You can either watch egay for a cheap carb to come up or buy new bits.

I would wait for a whole carb for £20 or something that hasn't been messed with, just taken off a wrecked bike or something.

Either way sounds bodged.

I don't know any of the code or part numbers but see if you can find another carb.

[MikeT]

Hi, just dredging up my old topic and asking for more help!

Thanks for the advice before, I got a replacement carb in the end, and all works well (more or less).

However, when I've just filled up the GS125, drive, then park, fuel shoots out the key hole of the filler cap.
Also, I get some fuel from somewhere lower, maybe the air filter!

So, it seems something is pressurising fuel out of the system.

I've tried not filling up so high, it helps, but I still get some fuel from down below, maybe a dribble from the cap.

So, does the GS125 have a tank breather pipe I haven't found that could be blocked? Is the only tank breather the fuel cap (which obviously breaths as fuel shoots out!).
Any other ideas why something would be forcing fuel out the system? Would it really shoot fuel out the carb into the air box, which then drips (I may have got this wrong, it's hard to find the source).

One hint, I've realised by down pipe has been 'slightly' squashed, but it doesn't seem dramatic enough to ruin the entire engine pressurisation or anything.

Thanks for any more tips!

Mike
____________________
-------my small bike collection:-
Suzuki GS125 ES (X?) 1999; Suzuki GP125 1984 (may soon be for sale, runs nicely for its age); Honda C90 1995

[chinthaka]

hi all
recently my brother bought a Suzuki GS125 we did a engine overhaul and it went well.. :D
any way i helped him with the carburetor tuning what i found inside the carb

pilot(slow) jet : 20
main jet : 95
float level : 24mm

* this one has a Brass Float ( I don't know whether all the other GS 125 has brass float, if it is why does this barb keep overflowing)

its a Mikuni VM carb and i really don't know which one is it. I measured the width of the intake side. it was 34mm

the problem is its overflowing gas when ever we turn the petcock on/reserve and it wont stop.. :(

we replaced float valve and the seat but it still overflowing. we looked in many forums all of them are saying to keep the float level at 24mm

so i was wondering..

1) Is there a different float level for BRASS floaters ??

2) is this jet configuration is correct for the carburetor (we live almost in sea level its not more than 1000ft from sea level)

3) what is the fuel consumption of a GS125 (this one does around 58 mpg)

any help is greatly appreciated

thanks in advance

thari