Re: gs 750 et fluffy at 4500rpm limiter? import

[cudaboy]

hello, new boy here,from wales in uk! hi all, suzuki nut and big mopar man! had 7 gs 1000, 3 gsx 750 et gt250,gt50 gsxr etc! have a gs750 16v 1980 <they called gsx750et here in uk> and at 4500 rpm looses power,pulls like mad up to that,its drawing vaccum well< balanced carbs,fuel and atu ok, checked out cdi on bench, even swapped coils today but no avail......are these limited in any way? the speedo max is 80mph,<canadian import> im struggling to get 70mph,its like the spark seems do dim at 4500 rpm, it still revs up but not quite right, any information be greatfully appreciated!

[TheCafeKid]

No limited as far as m aware on any GS(X) until the late late bikes. However are you running any sort of aftermarket exhaust or intake filter? Also your ignition advance mechanism may be sticking, or your ignitor gone bad..

[Redman]

Welcome to GSR.

No rev limiter.

What year is your 750? Reason I ask is to determine if electronic ignition or if braker points.

<<later note.
Oh, I should look at photo and reread your posting.
I see is a 80 , so would have electroinic ignition.

And I see it has aftermarket exhaust.
Do you know if it ever ran well with that exhaust?

.

[cudaboy]

Suzuki gsx 750

hello, atu opening up fine as rev up,no idea how ran with o/e exhausts,i got bike like this, the new pipe couldnt restrict bike that bad,ie in the way it is now, maybe give a flat spot etc the bike pulls like a train low down,real grunt just craps out like its lost compression must have some restriction as speedo ends at 85,not that it will do that as it is now but should reach 120 easy.

[cudaboy]

No limited as far as m aware on any GS(X) until the late late bikes. However are you running any sort of aftermarket exhaust or intake filter? Also your ignition advance mechanism may be sticking, or your ignitor gone bad..

cheers for info, have checked ignitor on bench, components all seem ok but no way to verify as did statically and not under load, are these ignitors two stage ie low rpm then mid/high? its like the low works fine and although still sparking at 4500 upwards not "clean"

[TheCafeKid]

Nah. Later models used a full CID type with electronic advance. Yours still used a mechanical advance as far as I know. Though someone witha better understanding of how they relate would probably be able to tell you, from what I understand early ignitors are a work/doesn't work item though one side is capable of going out.

With an aftermarket exhaust I'd suspect the jetting. May pull great down low and then starve up top coming on the needle and mains. A jet kit (stage one with just a pipe, stage 3 with pods and a pipe) is in order likely

[Mekanix]

Just an idea to test if its not fuel delivery, exhaust related

Connect a multimeter to the ignitor orange/white wire or the coil's O/W wire and drive it up to where it is causing the problem.

Mount the multimeter to something you can see clearly and see if it drops in voltage when you hit that bad spot.

I suggest this because nearing the 5000rpm mark you reach the maximum voltage and current the unit should be getting.

But at this point your also reaching a point where the ignitor sometimes doesn't have enough power to fire properly if it isn't getting enough voltage and current.

Good luck

[cudaboy]

Just an idea to test if its not fuel delivery, exhaust related

Connect a multimeter to the ignitor orange/white wire or the coil's O/W wire and drive it up to where it is causing the problem.

Mount the multimeter to something you can see clearly and see if it drops in voltage when you hit that bad spot.

I suggest this because nearing the 5000rpm mark you reach the maximum voltage and current the unit should be getting.

But at this point your also reaching a point where the ignitor sometimes doesn't have enough power to fire properly if it isn't getting enough voltage and current.

Good luck

many thanks that makes perfect sense! have decent multimeter,im convinced it electrical as its in same spot where goes wobbly! i do like simple mechanics, like my other toy....440ci, but thats another forum lol

[cudaboy]

Just an idea to test if its not fuel delivery, exhaust related

Connect a multimeter to the ignitor orange/white wire or the coil's O/W wire and drive it up to where it is causing the problem.

Mount the multimeter to something you can see clearly and see if it drops in voltage when you hit that bad spot.

I suggest this because nearing the 5000rpm mark you reach the maximum voltage and current the unit should be getting.

But at this point your also reaching a point where the ignitor sometimes doesn't have enough power to fire properly if it isn't getting enough voltage and current.

Good luck

hello, 12.35v on both orange/white wires to coils at 5000 plus rpm so back to carbs/exhaust.any idea if gsx600f carbs fit? i checked inlet rubbers for air leaks while running with a spray and no change in rpm so they ok.....

[Big T]

any idea if gsx600f carbs fit? i checked inlet rubbers for air leaks while running with a spray and no change in rpm so they ok.....

This is not a reliable test for air leaks

Have you taken the carbs off and actually examined the inlets?

Not running past 4500 is a classic lean problem

Do you have the airbox on when you are trying to rev it up?

I'm guessing you have nothing on the carb mouth

[BassCliff]

Greetings and Salutations!!

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Thank you for your indulgence,

BassCliff

[hampshirehog]

Big T is probably on the numbers - classic lean condition.

You'll need to check the intake rubbers (nice and soft, no cracks, tight fit), vacuum hose ( no cracks or other leaks), fuel tap (allowing plenty of fuel through and not partially blocked / diaphragm not opening up fully) and if that lot is ok check your carbs are nice and clean / diaphragms aren't rotten / punctured.

[cudaboy]

Suzuki gsx 750

oh dear.........oh dear..........i know the price of fuel over $2 a litre here but WINDING all the air screws in to a point one bent................., new ones ordered,in all the way then 3 . 5 turns out? cheers for all the input should have looked at these first now fitted and refitted carbs, bloody raining here to go out and test.....

[cudaboy]

yippie!!!!!!!!

just took for spin, pulls pulls and PULLLLLLLS!!!!!!!!!!!