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Discussion Starter #1
I have just purchased a 1997 GSXR 600 SRAD.

I bought the bike knowing that there was a fueling issue, the guy said that once it warmed up, it was bogging low down.

I picked up the bike and sure enough he was right.. but more severe, when pulling away from a standstill anything before 1/4 throttle is embarrasing.. it just bogs and crawls upto speed.

The revs also hang when you blip the throttle and when riding it stutters upto about 8,000 rpm.

All vacuum lines are in good condition as are the inlet rubbers.

I have since stripped and cleaned the carbs.

The main jets were -

1 and 4 132.5
2 and 3 130

Pilots were all 15.

I did notice that cylinder 1 carb when you move the valve body up and down there is significantly less suction and "woosh" compared to 2,3 and 4.

The diaphragm looks in good condition with no tears.

All o rings are also present and ok.

I did also notice that on cylinder one carb the diaphragm body/slide has a machined hole in the centre, whereas 2,3 and 4 do not.

Pilot air screw were set to 3 1/2 turns out on 1 and 4 and 3 turns out on 2 and 3.

The float needles are also in a good condition.

The diaphragm needles do have circlips, 3 possible positions, they are currently on the middle setting with is positon 2 out of 3

Any ideas or advice would be appreciated.
 

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Discussion Starter #3
Start with replacing the drilled slide with one that isn’t drilled.
Thanks for getting back to me so quickly, so someone has purposely drilled that hole? i thought it might of been from factory, seems strange.

Your saying i should get the standard jets too then?

Thanks again.
 

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Discussion Starter #4
Start with replacing the drilled slide with one that isn’t drilled.
Ok so here is where we are at, i replaced the drilled slide, fully stripped the carbs again and cleaned out, tried every since adjustment on the pilot air screws and it is still bogging / hesitating.

All the diaphragms are in good condition, needles are straight and are on the centre position for clips, the only thing i can think of is maybe an air leak from the rubbed tubing joints which go upto the airbox?

The joins are very soft from what i presume is years of reacting to air and fuel, is there an easy or hard way i can check for air leaks?

I have ordered standard jets but which what is going on in the world currently they are taking a long time.

Not too sure what else to try apart from pursue a "possible" air leak.

Any ideas?
 

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Usually easier to just leave the airbox off and tank propped up while tinkering around with getting things just rite at first.

There are some small jets within the tubing of the soleniods, might be worth confirming you even have those.

The air mixture screw can pretty much be set at 2.5 turns backed out from fully seated and just ignore them after they're set.

Bench syncing the carbs properly should be good enough to have everything running properly.

Float Height at 7mm is a pretty good starting point.

When the new jets arrive and you replace them, that will eliminate the variable of worn out jetting.

If the carb's themselves have been adquately gone over and cleaned/serviced. The only other thing that tends to get missed is the float needles themselves and the float needle seat oring/bucket. Wonky stuff occurs when that oring wears out.

But if you're still having problems after you've confirmed the carb rack is good to go by doing the above things, and get the idle properly set after warmed up and ridden around a bit. You might need to consider looking at other things as a potential cause of problem.
 

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Discussion Starter #6
Usually easier to just leave the airbox off and tank propped up while tinkering around with getting things just rite at first.

There are some small jets within the tubing of the soleniods, might be worth confirming you even have those.

The air mixture screw can pretty much be set at 2.5 turns backed out from fully seated and just ignore them after they're set.

Bench syncing the carbs properly should be good enough to have everything running properly.

Float Height at 7mm is a pretty good starting point.

When the new jets arrive and you replace them, that will eliminate the variable of worn out jetting.

If the carb's themselves have been adquately gone over and cleaned/serviced. The only other thing that tends to get missed is the float needles themselves and the float needle seat oring/bucket. Wonky stuff occurs when that oring wears out.

But if you're still having problems after you've confirmed the carb rack is good to go by doing the above things, and get the idle properly set after warmed up and ridden around a bit. You might need to consider looking at other things as a potential cause of problem.
My carbs do not have solenoids, it is an early 97 UK model.

If i put the mixture screws to 2.5 turns out it floods and dies.

Bench synced and they are still not running correctly.

Float height is set to 7mm, still no good.

The jets which are currently in there look like new, no corrosion or blemishing.

The float needles are like new also with no wear.

The only thing i have not done is the float needle seats, i cannot see an easy way to get them out, there is a screw with a washer holding the seat to the carb body, once undone i have tried to pull them out but the seem to be very stuck, they to wobble from side to side but do not slide out, any ideas?

Thanks again for the reply, i will wait to hear your thoughts :)
 

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The float seat buckets OEM new are fairly costly. They are only retained by the O-ring and the set screw you mention. Old rubber and such. If you do manipulate the seats, or remove them, chances are you will end up needing to manhandle them a bit and replace the seats + O-rings + needles.

It sounds like you've gone over everything else that would be a factor within the carbs.

If you own a sync tool, connecting it up might let you know if your problem is isolated to one carb/cylinder or all 4.

But other than the seats, if that doesn't do the trick, might be time to test/check/inspect other components.
 

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The only thing i have not done is the float needle seats, i cannot see an easy way to get them out, there is a screw with a washer holding the seat to the carb body, once undone i have tried to pull them out but the seem to be very stuck, they to wobble from side to side but do not slide out, any ideas?
they can be a BITCH for sure, I had to use a vice grip I modified to get grip on em , most tools like pliers what not have like a rounded edge, or rounder, I ground my vice grips so they were actually angled backwards so they have an angle on em and like a dyke situation for grip, I was able to carefully grab em and spin em at first them pull em out.. frozen is is right, man they dint wanna budge..

also if you have air you might be able to plug all the fuel inlets and then plug the one you are trying to remove and use air to help push it out after you use some penetrating fluid on it for over night or so.. try to loosed that o-ring up, they do get stuck but essential to replace so you know you have a solid base to work from..
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very hard to troubleshoot if your base isn't in 100% working order..

maybe use air and a pair of dykes with penetrating oil and work em out real slow
 

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Have you had a look at the fuel pump, fuel tap etc. to confirm that you're getting good flow?

What condition are your plugs in?

Dave
 
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