After taking my carbs apart twice and replacing whatever was needed I still have an ongoing issue . The syptom . After riding at a highish - 75mph + speed for quarter of a mile or accelerating with the throttle wide open to a higher speed the stutters and only starts pulling normally after I slow down and run with the throttle less than half open and after a while ( a couple of miles at most ) the throttle response is normal again ... It feels like a loose one side.
  After the first cleaning it was briefly  improved , initially I though it was solved. After this more careful clean its back to how it was at the beginning.
I wonder if I need to  furthur clean by boiling the carbs in  lemon juice or similar. I also wonder what else may cause this symptom - the bike pulls well up to about 95mph  but if i maintain over 75 I get the issue. Its an 89 gs slingshot with 54000 on the dial so could be pretty worn but I like the bike- its a lot of fun  on smaller roads flinging it about - 
  So , anythoughts ... Have tried the cleaning and messing about with the fual air mixture , cleaning the tank and  fuel filter ( will re-check that)  and no joy .. as i said it was better befor the last carb clean
  Could an air leak lead to this ? or would that manifest immidiately at speed  not after high speed riding for a spell as described- thinking .. rubbber book leaks or fuel pipes restricted ... its not a petcock issue or a problem with the fuel overflow/air pipe on the tank  I am running on prime and have had the issue with the tank cap open... tis giving me headaches fixing this issue --- otherwise its basically a hoot ... Hope you can help ...thanks for reading

Should say ... I cleaned the carbs well both times with carb cleaner and use q tips as needed and replace the flaot needles as needed .... and i have a rebuild kit though the other jets etc look fine and are now immaculate..

Fuel filter would be my first check, I have a history with those.

If you have one in-line chuck it.  It's not necessary.
If the one in the tank is clogged consider replacement.

Sounds like classic low float level, if you have ruled out the fuel delivery system. Also if the overflow hose opening is facing front it can cause this kind of behavior.

Thanks , i will check the filter and then look at the float heights.... Float height could  make sense  as its possible they have always been low as the bike came to me with this issue ,,, \\off to look for a picture and advice about measuring float height .. Thanks Watcher and Mr72

I had this happen when I put 01-02 carbs on my 95. I never could figure it out. Eventually I had to have it running, so I threw the 89-00 carbs back on and it worked perfectly. It wasn't in my tank, petcock hoses or anything. It was just something in those carbs.
Hope you figure out and post back.
Cool.
Buddha.

Well  cracked it , or so it seems . Afte taking Mr 72`s advice I reset the float level and flaboom it seems good . I say seems because it did this once before though this time i really gave it some beans  and it was faultless... going on a proper ride later when I have the time to be sure  but it seems ok . The foats were off , it seems the previous owner had set them both the same but a fair bit out - either that or the new float valve needle things had changed it and the cleaning  solved a seperate issue ... seems good now though ... thanks to you all ... Glad it wasnt  more tricky Buddha ..fingers crossed

Quote from: jackinacabin on July 21, 2018, 09:23:18 AM
Well  cracked it , or so it seems .

Great news! Sucks that the problem was one that required you to pull the carbs again but I bet you're getting good at it by now.

I am ... and after furthur ,,, ahem ... testing - all is well .. great little bike .. thanks for the aid

Mine had floats set correct. I suspected the floats getting high, every test U tube etc etc were all on the nose.
Only think I noticed was that the pilots seemed to have some gel like substance and had blue dots on them lower down, I thought it meant water incursion ... but never had I found the hole even remotely blocked. No idea, I am running 89-00 carbs and no issue even after weeks of sitting in the rain.
Cool.
Buddha.

Well I am all for If It Aint Broke .... No idea about the blue blobs ....  sounds like plague! .. But as the 89 carbs are working that seems like a good solution ... When mine has been very wet  it can spluuter on one side for a while - I think the wet  gets into something electrical , possibly a coil ... it passes so I have not chased the issue . Being an old bike there are other issues to  deal with befor that .. but it sure is fun to ride now - and a deal smoother since riding fast - it seems to have improved the engine throughout the rev range...

For anyone with similar symptoms....maybe also check the vent hole in the petrol cap.

Mine has a welded in vent on the top with a freeflo on it.
Cool.
Buddha.