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GSX750ES REVS SUPER HIGH AVTER INSTALLING CARBS


SATANSAM

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Posted

you need to do a bench test on the leaking carbs to find out exactly where they are leaking from.  a common problem is the rubber tip on the float valve will wear and then fuel will leak out into the airbox or down into the cylinders. 

  • Like 1
Posted

Well, I started the bike again before disassembling the carbs, sprayed propane round the manifolds and airbox with a blowtorch (Correct) Disassebled the carbs - I changed pilot jet for a another one that I cleaned with vinegar, petrol, solvent, spit, piss, compressor gun and god know what else...Inspected the diaphragm and it was correct...So was the needle...So I mounted the carbs in, starded the bike and it didn't rev up! It actually stalled when I inscrewed the idle screw...So, I think the refference carb (3) is now correct with low revs at last (I think it was the carb) I'll get the mixture done and then balance...Fingers crossed....THANX AGAIN FOLX!

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Posted

Well, all the same....Installed the carbs, high revs, unscrewed the idle screw until it din't touch the swing throttle arm, released each balancing screw (the 3 of them), mixture more or less in it's place blablabla...but for the carbs to be synchronized the bike has to reach about 3000rpm!!! Crazy...No air leaks anyware, nothing.....

As you can see, in the pic with all 4 gauges cylinder 3 hasn't got as much vacuum (it could mean there IS A LEAK SOMEWHERE!)....theres no way I can get all 4 the same, that's the closest I can get and over reved...Tried with new ignition coils and everything the same....All electrics are correct (I even bought another 2nd hand rectifier in good condition)...

Man, frustration isn't the word.....If any of U still have any ideas Lemmy know...I'll be in the pub drinking  directly from the tap.

Thanx again amigos 

IMG_20201211_184037.jpg

IMG_20201211_183019.jpg

Posted

If the bike seems to to run OK at 3000 rpm but runs poorly below that I would suspect that you still have a blocked pilot/bleed jet.  At 3000 rpm the fuel will be metered by the needle jet and the mains, which being big holes are unlikely to block!  Below 3000 you are in small jet territory. I would suspect the small jet behind the rubber bung/plug next to the main, it's very prone to blocking, especially if your rubber plugs have been hardened by the ethanol in modern fuel.

Hope this helps.

TonyC

  • Like 1
Posted
On 12/12/2020 at 3:25 PM, TonyC said:

If the bike seems to to run OK at 3000 rpm but runs poorly below that I would suspect that you still have a blocked pilot/bleed jet.  At 3000 rpm the fuel will be metered by the needle jet and the mains, which being big holes are unlikely to block!  Below 3000 you are in small jet territory. I would suspect the small jet behind the rubber bung/plug next to the main, it's very prone to blocking, especially if your rubber plugs have been hardened by the ethanol in modern fuel.

Hope this helps.

TonyC

It helps, thanx again Tony... By the way I found a cool short video with this same problem: 

 

Posted

Hi again....Does anyone want a free gsx?!?!

I re-cleaned the carbs, all the jets, compressed air, all parts assembled according to the manual...Diaphragms, needle, jets, floats, gaskets...Everything correct...Mounted the carbs, did the mixture with Gunson, calibrated the balancer and connected it to the carbs and the same happened: For them for to be balanced the bike has to be round 2000 or 2500 rpm, and I think it has to do with cylinder 3 (refference), or with the other 3... Look at the photos, cylinder 3 has more compression than the rest....I'm totally lost, and scared if something has gone wrong with the valves or something....But its strange, about 3 weeks ago I adjusted the valves just like they are now, the bike runned superb! But the carbs were dirty, stripped them out, reassebled them and this thing happened...Strange....I'm doubting if I did something wrong with the valve clearence....

Pix of the compression of all 4 cylinders....Weird....

Cylinder 1.jpg

Cylinder 2.jpg

Cylinder 3.jpg

Cylinder 4.jpg

Posted

are they showing 90psi ? if so thats too low. did you have the throttle wide open when cranking ? and number 3 is higher than the rest so the valve must be ok. i wonder if all the rest are too tight ? i think you need to go back in and recheck them. 

  • Like 1
Posted
5 minutes ago, TonyGee said:

are they showing 90psi ? if so thats too low. did you have the throttle wide open when cranking ? and number 3 is higher than the rest so the valve must be ok. i wonder if all the rest are too tight ? i think you need to go back in and recheck them. 

I'm even thinking I read the clearence the wrong way round!!!!Na, I'm lost...Crazy crazy crazy...

Thanx Tony

Posted
1 minute ago, TonyGee said:

a new engine will show around 170psi service limit around 120psi. anything below 100psi isn't good. recheck the valve clearances :tu

Will do T! Must of done it the wrong way round...Cheerz m8!

Posted
Just now, SATANSAM said:

Will do T! Must of done it the wrong way round...Cheerz m8!

no problem, good luck. before you do any carb or ignition adjustments an engine must be in good health, if not you are pissing against the wind. ;)

  • Like 1
Posted
On 12/9/2020 at 9:27 PM, SATANSAM said:

when balancing the carbs was that when I tuned number 2 carb to the 3 (reference carb) the bike reved up more

When you were ultrasonic cleaning the carbs, did you split any of the carb bodies from their rack? I'd check for missing springs under the balance screws. it's the springs which keep the butterflies shut.  

Posted
4 minutes ago, Jaydee said:

When you were ultrasonic cleaning the carbs, did you split any of the carb bodies from their rack? I'd check for missing springs under the balance screws. it's the springs which keep the butterflies shut.  

Hi Jay,
No I didn't split the carbs (The springs are there) I just cleaned jets, inspected for holes in diaphragms and checked float hights...Everything takes me to a wrong valve clearence the other tay :S Going for a pint I've had enough! Thanx guys

Posted
Morning folx,
I think I've never written so much in a forum... just a pic of the manual from the clearance part....Seems the motor is the other way round in the manual (they identify cyl 4 as 1) and I might of done the clearence according to the photo instead of the explanation (The explanation written is correct).
In the valve clearance explanation the motor is upsidedown and they say to check clearance in cylinder 1 to start with (notches pointing out), but motor is upsidedown and it's number 4, Isn't it?
 
 

C989935D1.jpeg

C989935D2.jpeg

C989935D3.jpeg

Posted (edited)
17 hours ago, SATANSAM said:

Hi again....Does anyone want a free gsx?!?!

Nah - apparently it runs like shite! LOL!

There is something definitely awry with your valves ..................... or your engine is worn out! 

Edited by Gixer1460
Posted
13 minutes ago, Gixer1460 said:

Nah - apparently it runs like shite! LOL!

There is something definitely awry with your valves ..................... or your engine is worn out! 

I don't like it but U R right

Posted
11 minutes ago, TonyGee said:

number one cylinder is the one on the left as you sit on the bike, so the pic's are correct. 

This is what I meant...Na, don't know...I'll try once again this afternoon...It was running superb before all this.

NOTCH.jpg

Posted

to make life easier for you do one cylinder at a time, all you have to do is make sure the high point of the cam lobe is facing away from the valve. then check/adjust the valve clearance.  

Posted
1 minute ago, TonyGee said:

to make life easier for you do one cylinder at a time, all you have to do is make sure the high point of the cam lobe is facing away from the valve. then check/adjust the valve clearance.  

Thanx Tony...Dammit I've lost the las neuron I had.

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