Well ive been in every forum of every gsxr website and talked to every suzuki tech around and they have no idea what is wrong with my bike.

heres the deal I rebuilt the motor because it needed rings.about 8K miles ago and its ran fine, perfect actually, until about 500 miles ago. the problem is that when the motor is under load via throttle it bogs down and actually cuts out in 2nd gear.

heres what ive done so far.

1 cleaned/rebuilt carbs, tried every possible jetting, and swapped carbs from good bike
2 swapped coils
3 swapped cdi
4 swapped pulse generator coil
5 removed sidestand switch
6 removed clutch switch
7 new battery
8 cleaned tank and prestrainer is clean
9 fuel pump primes
10 vaccumm diaphram opens to allow fuel flow when vaccumm is applied
11 no airbox restrictions
12 power to everything
13 grounds good
14 no shorts/opens found in wiring
15 no burn marks in start/run switch and operation is good
16 no defects with ignition switch found. key turns good and no abnormalities when riding from jiggling key, pulling harness or knocking on switch.
17 no exhaust leaks

all this and it still bogs when under a load/ wide open throttle when fully warm only cutting out in 2nd gear.

I HAVE STUMPED MYSELF AND ABOUT 20 OTHERS....i need some serious help. could a slightly leaking petcock do this? i dont think so but that the only problem ive found that out of the ordinary so far. thanks for the help guys!

so what year bike and what is it 600 or 750?

have you checked the fuel filter inside the fuel line?

yes and its spotless not even a speck of trash......fun problem huh?

ohh and its a 600 with bolton yosh RS3, jet kit, and a K&N.

Here's an idea from a similar problem I had with a Honda. Under heavy load you're pulling the most vacuum. It's possible that there's a small hole in the fuel pressure regulator's diaphragm. If the vacuum moves the diaphragm to a position that exposes the hole, fuel will get sucked into the vacuum line, dumped into the intake runners, and choke the engine.

The tell tale sign is fuel in the vacuum line. If the problem arises and goes away once the engine is idling, the fuel may dry out and not appear there. But, to be sure, you could try reproducing the problem and when it's significantly bogging down, kill the engine. Push the bike back to your garage and check the line. You may also find fuel puddling on top of the closed intake valves.

That was a tricky problem for me to diagnose, but once I figured it out, all the clues suddenly made sense. And luckily, that's a cheap and easy fix.

Does it still do it with airfilter(s) off?

hmmm... sounds like something that happened to my buddies 96 750. We spent hours trying to figure it out...

Turned out that after riding for a few miles his airbox would lift off the carbs a little bit and that would break the seal (boots on the carbs), then it would bog out under load...

We ended up cutting off the front tab that bolts the box to the frame so the front of the box would sit a bit lower and the boots would then sit at the right angle on the carbs... problem solved.

well i put a vaccum pump on the vaccum line and pulled a vaccumm on it and it opened the main fuel line but didnt notice any fuel coming down the vaccum line...HOWEVER...i do have fuel that seems to be in noticable quantity on the inside intake boots after sitting for a period of 3 days. this i believe is due to the slightly leaking diaphram for the petcock. but could a slightly leaking petcock cause to much fuel under load when the needle valves are suppose to shut fuel to the carbs?

There was a factory recall on early 96 fuel valves, which were swapped out at the dealer. I would start by replacing the valve and see if problem gets better also check fuel pump and filter. Good luck:cheers

no a leaking pet cock cannot cause this.. the floats will only open when there is more then 4psi of fuel pressure.. and the stock carbs have some sort of pressure relif shit in them, thats what all the crap at the bottoms of the carbs are..

i had sorta a similar problem, i just swapped carbs and it went away, later on it happend to my mates bike with very simple carbs, easy to figure out, and it was 2 of the diaphrams werent sealing properly allowing the slide to lift to far, and extreamly lean out the bike.. but uve swapped carbs so i dont think its that.. so i sorta wasted time typeing this lol

well i still appreciate the input and comfirming its not a petcock issue. could a misadjusted cam chain do this? if it was slack (not to where it caused noise but just slack)

The gas inside the boots after 3 days of sitting sounds like a bad needle/seat.

I really hope you find whats wrong with your bike northgagsxr. Mine does the same exact thing. I havent been able to ride my bike in almost 2 years, ive had every good mechanic i know look at my bike, spent almost $1200 trying to fix it & its at the 3rd shop right now.

I cannot understand why noone can fix this. Ive tried everything & im at my last with this bike. If this shop cant fix it then my only option is to part it out, but its a shame b/c i love this bike & it really is a nice bike.

if you figure this out please let me know what the problem was! thanks

haha its the curse of the blue and white gixxers....i know 4 of us with same years and graphics with this issue. i cant take it to the shop....they said all they can do is part swap and ive swaped all the parts. even checked my compression and leak tested the motor and everything is perfect. i wonder if anyone on this website has contact with suzuki directly?

this may or may not be of any help but I have had very simular problem and it turned out to be gas tank venting.

Yes ive explored that and it vents fine...no clogged hoses. but i do appreciate the suggestion

the fluxcapacitor is bad.... DUH

i wondered when the immature comments would pile in...it would be funnier if u said something other than flux capacitor. like its the incorrect installation of the crossdrilled brake lines with the lefthanded metric screwdriver

no thats just gay

I have seen bad ground wires or just loose and bad connections for ground do weird things. Also check the crank position and cam position sensors are tight and haven't come loose. Check these areas if you haven't yet? Good luck:cheers

My 98 600 is doing the Same thing, and only in second gear. It blasts any other gear just fine but when it comes to second gear it blips like crazy. I get up to 4 very brief (as in less than 1 second) blips when I am hard on the throttle takeing it to the limiter. The blips are all through out the gear range too, not just up high or down low. Keep me posted if you guys find anything else out.

keep this thread going, i'm working on a 97 600 and it has the same problem, 2 factory shops had it for the last 9 months and they both gave up so I now have the problem to fix. I think maybe a TPS or something in the timing cause this one runs hot. anyone with the magic answer???

Ttt, Mine is starting to sound like a tooth is missing on my 2nd gear. If you guys are having problems with just 1 gear (specifically 2nd) let me know. I will be digging into it once the weather gets cold I guess... I'm also going to be looking into just swapping in a 750 motor....This problem blows:thumbdown So, should i break the motor open and just replace the gear? Or should i just swap in a 750? I'm looking for keeping this cheap and as fairly simple as possible. Thanks,

~Tony

Okay, so you are saying that under a load(meaning wide open throttle) it bogs down, and if you say you've checked fuel and air and everything is within specs. then I might assume that your problem is electrical. What gets me, is how you say it only cuts out in second gear. There's nothing really special about second gear, the only thing I can think of that might be related to second gear would be the neutral switch between first and second gear.

I would agree that timming sounds like problem. Has any one had the top cover off and looked at the cam shafts and chain. also the cam chain adjuster. my 97 gsxr600 the cam chain adjuster went bad but slowly and my bike ran bad. i cleaned carbs and stuff like that but then one day my bike sounded like a diesel. i shut it down and tore it down and sure enough cam chain tensioner had went out luckily i caught it early. but when i swapped it out the bike ran good sound wise but had no power because timming was out by one tooth. i tore it down and set up timming and it has been running fine since. hope this helps

+1 stikisidedown

figured out anything yet? mines still down.