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05 Suzuki Gsx750f, Idling high help please

9K views 12 replies 4 participants last post by  Aussie Steve 
#1 ·
Hi everyone,

I'm new to bikes, and just got my first one. I purchased a Used 05 gsx750f 10k miles and it was running fine when I first got it. 2 days later my father took it for a test ride, with realively close to no gas in the tank. He stalled, due to the low amount of gas in the tank as we believe. After that it now idles high, I waited a few hours for the tank to cool to add gas to the tank, and to no avail it is still idling high.

Basicly my first question is, do you think that the stalling because of no gas could cause this problem,
Secondly if so how do you correct it.

I've done some research on maybe adjusting the idling screw, or oiling the choke line. I currently don't have the tool at the moment to oil the choke line but I will try that tomorrow, but I'm not full certain where the idling screw is (as I stated new to bikes, and New bike.) I tried googling it and still haven't found the answer so I'm now turning here for help.

any input would be great.
 
#2 ·
the idle screw should be a large hand adjustable screw attached to the carbs.

if there is not a fuel filter( and sometimes even if there is) sediment from the tank could be causing something in the carbs to stick.
it may be hidden behind your fairings.

the 1st step i'd do is get a can of b12 chemtool or gumout carb cleaner and put a couple of oz in the gas tank. that should help sort any small debris. run it like that for a little and see if it helps it out. if not then adjust the idle screw.
 
#3 ·
Just checked these are carbed correct?...my guess would be as Slozomby suggested carb related....maybe the choke is sticking or a tiny bit of crap is holding something open. Do as suggested and after getting it circulated leave it overnight.
 
#4 ·
And while you are waiting for the chemical treatment to work.......check the operation of the throttle cables and the choke.

Stalling had nothing to do with this but, as stated, being LOW on gas might have. Was it ever switched over to REServe ?

It's more likely that a human error occurred when trying to restart it......like leaving the choke partly ON......or accidentally turning the idle screw.
 
#5 ·
The choke I believe is working fine, when pulled down it will cause the rpms higher, the throtal cable seemed to be loose, and I tightened it causing it to stall out. The bike was started on RES, by my dad when the gas was low. I messed with the idling screw and it went too low that the rpms caused it to stall out after getting back up an running is when I messed with the throttle cable, and thus did the same thing on tightening after loosening it first now it caused the rpms to fall too low and stall out, now I can't get the bike to turn over while trying to bring it back to the working condition it was in a few mins earlier I don't want to burnout the starter so I'm taking a break for a moment.


Probably going to pick up the gum out
 
#7 ·
UPDATE:

I can get it idling correctly until using the throttle with a significant amount of gas, then it seems to idle high, 2500 - 3000 rpms until I touch the idle screw again or wait a little. Almost like something is stuck. If I use little busts it does not do that. Putting the gum out in now, while I wait anything else can mess with, or should I get the tool and oil any the cables?
 
#8 · (Edited)
generally fiddling with 1 thing at a time is the best troubleshooting procedure. you might fix the sediment issue and cause a different problem with something else you messed with.

it sounds like the choke is working fine from your description.

you might consider adding in a fuel filter into the mix while your waiting. that should not affect anything.
 
#9 ·
Added the gum out carb cleaner about a 3rd of the bottle, after letting it run for a few minutes it started to white smoke, around the carbs that's the point I turned it off. Now I'm letting it sit, but it was still idling high when I shut it down. I could get to idle at about 2000 to 2500 around this time, anything lower while cause it to slowly lose rpms until it stalled out. How long should I wait before I try starting it again, as well as should I already be seeing some changes by now?
As far as the fuel filter goes, I don't think I can get my hands on one of those today.
 
#10 ·
Did you actually read the directions on the Gumout ?? :roll:
Depending on how big the bottle is and how much gas was in the tank.......that might be WAY too much.

The white smoke might be an indication that it is doing it's job......but the smoke should NOT be coming out of the carbs themselves.
THAT might be an indication of the other common cause of high idle speed and poor running at idle: That is, a vacuume leak around the carb(s).
One way a vacuum leak happens is if the vacuum hose to the petcock comes off........like when someone not familiar with it is fiddling around trying to find REServe.

At this point, you need to charge the battery too.
Running it down too far, and leaving it there, is VERY hard on it.
 
#11 · (Edited)
I did read the directions, and defiantly tried to pour less lol that's why I didn't use the whole bottle but I do think the smoke is coming out of the carbs. It looks like he white smoke is coming out underneath the gas tank, but I can't pin point where. as for the hose and the petcock, how would I go about checking this, and my dad may have done that.....


Also, would the petcock hose only cause high idling when the engine is warm?
 
#13 ·
If the fuel line/s are old they may collapse whilst riding starving the engine. You may also have damaged or missing rubber parts from the carbs....also if the inlet manifolds carb ends and airbox ends are overtightened they can leak. Lots of things this could be so... as suggested one thing at a time.

One other thing is the throttle cable adjusters up by the handlebars...if fitted....one is a pull cable when opening the throttle and the other is just following the movement of the linkage the reverse is true when the spring at the linkage pulls the throttle closed. If this is set up too tight the throttle can hang causing undue rpm. Also the return spring linkage must be in good condition and assembled correctly...you should hear a clean crisp snap as the throttles close when letting go at any position of open throttle.
 
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