93 GSXR1000 carbs

[DiverRay]

Cat,
I CAN do my own in about 20 minutes. If I work on other carbs, as I do, I need to start from an unknown baseline. They usually take about an hour, but I HAVE had other problems get in the way. I have one set I need to go over again, once new coils are installed......

[audijunky]

So, Monday evening get all the mix screws set t o2 1/4 turns out. open up the top of #4 to adjust needle hieght and figure not to do it and see how it is with the screws set. So put the carbs back on. and start it up. idling nice, when I bump the throttle pretty good it stumbles, and actually died once. I could rev it up slowly and it sounded pretty good. So decide to take it for a spin, in first at low RPMs running crappy ,sputtering hit 4 k and she takes off like a rocket. SO I am thinking "sweet" atleast I got the main jet and possibly the needle height right. Wrong, after about 1- 2 mins. It starts running like crap at the top end too, missing feels flat . So I get back and pull the plugs and the electrodes are white/lite tan. Look over at my bench and see guess what....................wait for it

My diphram spring from carb #4 sitting on the bench.
Anywho going on a trip for work Saturday, and will have some pod filters waiting for me when I get back. I am going to put those on, and build myself a little y pipe collector to connect my exhausts pipes to give me a 4-2-1 no baffle exhaust. After that I am gonna resume tuning. No sense getting crazy trying to tune it now with no filters, and a 4-2 w/no baffles. I will post up again when all that is completed. Atleast I know now these carbs work sort of

[Shuriken]

No sense getting crazy trying to tune it now with no filters, and a 4-2 w/no baffles. I will post up again when all that is completed. Atleast I know now these carbs work sort of

+1 on your tuning logic.

If #4 diaphragm spring was on the bench and not in the carb, that would definitely give you some trouble....

Post back when the spring is back in and when you have the pods installed.

[audijunky]

Allrighty then
Got some pods on them, reinstalled #4 diaphram spring. Also dropped needle clips down to the last notch on the needles. Taking off it is a dog stumbling, moving but not right, hit around 5k and she backfires than starts to windup pretty good, hit about 8.5-9 k and she flatlines. Didnt check plugs yet, dont really got the room to do a high rpm plug drop. Really need a carb sync. Anyway I am leaning toward lean on the bottom and top end. upper level rpms I dont know whats going on. I really need a carb sync and a dyno A/F ratio test. Thinking about resetting my mix screws to 2 1/2 or maybe 3 turns out. What say you all?

[T99Ford]

Do you mean the top notch on your needles, or the bottom notch? I would think that you would be wanting to lower the needles rather than raise them, but this supposes that the bike is rich in the midrange. If you are in the bottom notch, then you are probably running way to rich in the bottom midrange, causing that terrible bog.
I would do the carb sync first before anything else, so that you have at least that part tuned correctly. Then start with the jetting, etc. Adjusting the mixture screws will only affect decel and idle, but wil not have much effect over that. Dyno if you can, but if not, check your midrange for being rich. It is really easy to do. Good luck!

[Ivan]

Its times like these when a good exhaust sniffer and a dyno would be so much help. You could actually see where it is lean and rich.

I feel for you. I have been down the tuning road... Adjust only one thing at a time and pay close attention to it making things better or worse. if it doesn't make much of a change, its probably about right, and time to look else where.

[Shuriken]

Allrighty then
Got some pods on them, reinstalled #4 diaphram spring. Also dropped needle clips down to the last notch on the needles. Taking off it is a dog stumbling, moving but not right, hit around 5k and she backfires than starts to windup pretty good, hit about 8.5-9 k and she flatlines. Didnt check plugs yet, dont really got the room to do a high rpm plug drop. Really need a carb sync. Anyway I am leaning toward lean on the bottom and top end. upper level rpms I dont know whats going on. I really need a carb sync and a dyno A/F ratio test. Thinking about resetting my mix screws to 2 1/2 or maybe 3 turns out. What say you all?

Are you confident that your main jet is correct? You really need to have that correct - first. Go rich enough on the main that when you do WOT, the bike pulls like a beast and has tan plugs. Once you have that right, work down from there. Just my opinion but I think it would make it waaaayy easier for you.

[T99Ford]

^^^^^ What Ivan said! It doesn't matter which jet you start with if you don't know where you are at.

[T99Ford]

And what Shuriken said....just not on the ball I guess

[audijunky]

well then next step, drop in some 140's
thanks guys

[petejw]

Hey Audi,
sounds like you could be rich in the middle(needle) and
lean on the mains.
What gear are you in when it starts running flat up high?

[audijunky]

first gear, with the little room I have to wind it, that is all I can do. Its wierd, but it backfires consistently when transitioning from mid to high RPMs. And right after the backfire is when she starts to pull hard. I dont know if that means I am rich going to lean or vice versa.

[audijunky]

Are you confident that your main jet is correct? You really need to have that correct - first. Go rich enough on the main that when you do WOT, the bike pulls like a beast and has tan plugs. Once you have that right, work down from there. Just my opinion but I think it would make it waaaayy easier for you.

No I am not confident at all. I mean these carbs came with 114 and it ran like poo with those in, So i dropped in the 137.5 from the XS carbs and it helped, but I dont know if they are exactly what I needed.
With the XS carbs on my top end felt spot on, and I was running 150 mains!! I dont know what these carbs need with my motor/setup. All trial and error right now trying to figure it out.

As of now I got 93 GSXR 1100 carbs ( I know the thread title says 1k)
pod filters, 137.5 mains, needle clip on last position down, 42.5 pilots, mix screws 2 1/4 turns out, 4-2 straight pipe exhaust w/washer inserts to add some back pressure.
starting in first: WOT -low rpm up to about 5 k she is weak, bogging sputtering at around 5-6k rpm backfires than feels like I got shot out of cannon up to about 8-9K rpms than she flatlines. Thats all I got. Plus while doing all my little tweaks and such the plugs always look lean, but that is overall color not a certain RPM's color.
thanks for all of your inputs, as soon as I do something else I will post up again.

[petejw]

Its to hard to tell when youve only got the 1 gear to play with,
and if your on flat/declining ground when your testing you might not even be opening your mains completely (slides fully open).
I dont know any real way of checking the carbs without taking the bike out onto at least a highway. Sorry I know that doesnt help much.

[audijunky]

OK so I go to put in the 140 mains I have. BUT the 137.5's wont come out
Not only that they break off in the emulsion tube. SWEET JESUS
ALL of them broke off, whats the old staying 1 step forward 2 steps back?
thats about how my process is going. Managed to save one of the tubes with an easy out. the other three are toast. I may have overtightened while installing, they might have broken then cause I had to stick a small flathead under the top of the main to get that to come off after I had turned them trying to take them out. Anyways got an email out to Factory Pro. Hopefully they can set me up with some new and improved emulsion tubes, needles, and jets. They make kits for the GSXR but they dont list jet sizes.